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freebsd/sys/netinet/tcp_hpts.c
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Gleb Smirnoff 9b76228006 inpcb: retire inp_vnet 
Now that a functional inpcb can not outlive its socket, just use socket's
vnet pointer.
2026-04-14 09:02:00 -07:00

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/*-
* Copyright (c) 2016-2018 Netflix, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_rss.h"
/**
* Some notes about usage.
*
* The tcp_hpts system is designed to provide a high precision timer
* system for tcp. Its main purpose is to provide a mechanism for
* pacing packets out onto the wire. It can be used in two ways
* by a given TCP stack (and those two methods can be used simultaneously).
*
* First, and probably the main thing its used by Rack and BBR, it can
* be used to call tcp_output() of a transport stack at some time in the future.
* The normal way this is done is that tcp_output() of the stack schedules
* itself to be called again by calling tcp_hpts_insert(tcpcb, usecs). The
* usecs is the time from now that the stack wants to be called and is
* passing time directly in microseconds. So a typical
* call from the tcp_output() routine might look like:
*
* tcp_hpts_insert(tp, 550, NULL);
*
* The above would schedule tcp_output() to be called in 550 microseconds.
* Note that if using this mechanism the stack will want to add near
* its top a check to prevent unwanted calls (from user land or the
* arrival of incoming ack's). So it would add something like:
*
* if (tcp_in_hpts(inp))
* return;
*
* to prevent output processing until the time alotted has gone by.
* Of course this is a bare bones example and the stack will probably
* have more consideration then just the above.
*
* In order to run input queued segments from the HPTS context the
* tcp stack must define an input function for
* tfb_do_queued_segments(). This function understands
* how to dequeue a array of packets that were input and
* knows how to call the correct processing routine.
*
* Locking in this is important as well so most likely the
* stack will need to define the tfb_do_segment_nounlock()
* splitting tfb_do_segment() into two parts. The main processing
* part that does not unlock the INP and returns a value of 1 or 0.
* It returns 0 if all is well and the lock was not released. It
* returns 1 if we had to destroy the TCB (a reset received etc).
* The remains of tfb_do_segment() then become just a simple call
* to the tfb_do_segment_nounlock() function and check the return
* code and possibly unlock.
*
* The stack must also set the flag on the INP that it supports this
* feature i.e. INP_SUPPORTS_MBUFQ. The LRO code recoginizes
* this flag as well and will queue packets when it is set.
* There are other flags as well INP_MBUF_QUEUE_READY and
* INP_DONT_SACK_QUEUE. The first flag tells the LRO code
* that we are in the pacer for output so there is no
* need to wake up the hpts system to get immediate
* input. The second tells the LRO code that its okay
* if a SACK arrives you can still defer input and let
* the current hpts timer run (this is usually set when
* a rack timer is up so we know SACK's are happening
* on the connection already and don't want to wakeup yet).
*
* There is a common functions within the rack_bbr_common code
* version i.e. ctf_do_queued_segments(). This function
* knows how to take the input queue of packets from tp->t_inqueue
* and process them digging out all the arguments, calling any bpf tap and
* calling into tfb_do_segment_nounlock(). The common
* function (ctf_do_queued_segments()) requires that
* you have defined the tfb_do_segment_nounlock() as
* described above.
*/
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/interrupt.h>
#include <sys/module.h>
#include <sys/kernel.h>
#include <sys/hhook.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/proc.h> /* for proc0 declaration */
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/refcount.h>
#include <sys/sched.h>
#include <sys/queue.h>
#include <sys/smp.h>
#include <sys/counter.h>
#include <sys/time.h>
#include <sys/kthread.h>
#include <sys/kern_prefetch.h>
#include <vm/uma.h>
#include <vm/vm.h>
#include <net/route.h>
#include <net/vnet.h>
#ifdef RSS
#include <net/netisr.h>
#include <net/rss_config.h>
#endif
#define TCPSTATES /* for logging */
#include <netinet/in.h>
#include <netinet/in_kdtrace.h>
#include <netinet/in_pcb.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip6.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/ip6_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcpip.h>
#include <netinet/cc/cc.h>
#include <netinet/tcp_hpts.h>
#include <netinet/tcp_hpts_internal.h>
#include <netinet/tcp_log_buf.h>
#ifdef tcp_offload
#include <netinet/tcp_offload.h>
#endif
/* Global instance for TCP HPTS */
struct tcp_hptsi *tcp_hptsi_pace;
/* Default function table for production use. */
const struct tcp_hptsi_funcs tcp_hptsi_default_funcs = {
.microuptime = microuptime,
.swi_add = swi_add,
.swi_remove = swi_remove,
.swi_sched = swi_sched,
.intr_event_bind = intr_event_bind,
.intr_event_bind_ithread_cpuset = intr_event_bind_ithread_cpuset,
.callout_init = callout_init,
.callout_reset_sbt_on = callout_reset_sbt_on,
._callout_stop_safe = _callout_stop_safe,
};
#ifdef TCP_HPTS_KTEST
#define microuptime pace->funcs->microuptime
#define swi_add pace->funcs->swi_add
#define swi_remove pace->funcs->swi_remove
#define swi_sched pace->funcs->swi_sched
#define intr_event_bind pace->funcs->intr_event_bind
#define intr_event_bind_ithread_cpuset pace->funcs->intr_event_bind_ithread_cpuset
#define callout_init pace->funcs->callout_init
#define callout_reset_sbt_on pace->funcs->callout_reset_sbt_on
#define _callout_stop_safe pace->funcs->_callout_stop_safe
#endif
static MALLOC_DEFINE(M_TCPHPTS, "tcp_hpts", "TCP hpts");
static void tcp_hpts_thread(void *ctx);
static volatile uint32_t __read_frequently hpts_that_need_softclock;
#define LOWEST_SLEEP_ALLOWED 50
#define DEFAULT_MIN_SLEEP 250 /* How many usec's is default for hpts sleep
* this determines min granularity of the
* hpts. If 1, granularity is 10useconds at
* the cost of more CPU (context switching).
* Note do not set this to 0.
*/
#define DYNAMIC_MIN_SLEEP DEFAULT_MIN_SLEEP
#define DYNAMIC_MAX_SLEEP 5000 /* 5ms */
/* Thresholds for raising/lowering sleep */
#define SLOTS_INDICATE_MORE_SLEEP 100 /* This would be 1ms */
#define SLOTS_INDICATE_LESS_SLEEP 1000 /* This would indicate 10ms */
/**
*
* Dynamic adjustment of sleeping times is done in "new" mode
* where we are depending on syscall returns and lro returns
* to push hpts forward mainly and the timer is only a backstop.
*
* When we are in the "new" mode i.e. conn_cnt > conn_cnt_thresh
* then we do a dynamic adjustment on the time we sleep.
* Our threshold is if the lateness of the first client served (in slots) is
* greater than or equal too slots_indicate_more_sleep (10ms
* or 10000 slots). If we were that late, the actual sleep time
* is adjusted down by 50%. If the slots_ran is less than
* slots_indicate_more_sleep (100 slots or 1000usecs).
*
*/
#ifdef RSS
int tcp_bind_threads = 1;
#else
int tcp_bind_threads = 2;
#endif
static int tcp_use_irq_cpu = 0;
static int hpts_does_tp_logging = 0;
static int32_t tcp_hpts_precision = 120;
int32_t tcp_min_hptsi_time = DEFAULT_MIN_SLEEP;
static int conn_cnt_thresh = DEFAULT_CONNECTION_THRESHOLD;
static int32_t dynamic_min_sleep = DYNAMIC_MIN_SLEEP;
static int32_t dynamic_max_sleep = DYNAMIC_MAX_SLEEP;
SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hpts, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"TCP Hpts controls");
SYSCTL_NODE(_net_inet_tcp_hpts, OID_AUTO, stats, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
"TCP Hpts statistics");
counter_u64_t hpts_hopelessly_behind;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, hopeless, CTLFLAG_RD,
&hpts_hopelessly_behind,
"Number of times hpts could not catch up and was behind hopelessly");
counter_u64_t hpts_loops;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, loops, CTLFLAG_RD,
&hpts_loops, "Number of times hpts had to loop to catch up");
counter_u64_t back_tosleep;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, no_tcbsfound, CTLFLAG_RD,
&back_tosleep, "Number of times hpts found no tcbs");
counter_u64_t combined_wheel_wrap;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, comb_wheel_wrap, CTLFLAG_RD,
&combined_wheel_wrap, "Number of times the wheel lagged enough to have an insert see wrap");
counter_u64_t wheel_wrap;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, wheel_wrap, CTLFLAG_RD,
&wheel_wrap, "Number of times the wheel lagged enough to have an insert see wrap");
counter_u64_t hpts_direct_call;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, direct_call, CTLFLAG_RD,
&hpts_direct_call, "Number of times hpts was called by syscall/trap or other entry");
counter_u64_t hpts_wake_timeout;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, timeout_wakeup, CTLFLAG_RD,
&hpts_wake_timeout, "Number of times hpts threads woke up via the callout expiring");
counter_u64_t hpts_direct_awakening;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, direct_awakening, CTLFLAG_RD,
&hpts_direct_awakening, "Number of times hpts threads woke up via the callout expiring");
counter_u64_t hpts_back_tosleep;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, back_tosleep, CTLFLAG_RD,
&hpts_back_tosleep, "Number of times hpts threads woke up via the callout expiring and went back to sleep no work");
counter_u64_t cpu_uses_flowid;
counter_u64_t cpu_uses_random;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, cpusel_flowid, CTLFLAG_RD,
&cpu_uses_flowid, "Number of times when setting cpuid we used the flowid field");
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts_stats, OID_AUTO, cpusel_random, CTLFLAG_RD,
&cpu_uses_random, "Number of times when setting cpuid we used the a random value");
TUNABLE_INT("net.inet.tcp.bind_hptss", &tcp_bind_threads);
TUNABLE_INT("net.inet.tcp.use_irq", &tcp_use_irq_cpu);
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, bind_hptss, CTLFLAG_RD,
&tcp_bind_threads, 2,
"Thread Binding tunable");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, use_irq, CTLFLAG_RD,
&tcp_use_irq_cpu, 0,
"Use of irq CPU tunable");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, precision, CTLFLAG_RW,
&tcp_hpts_precision, 120,
"Value for PRE() precision of callout");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, cnt_thresh, CTLFLAG_RW,
&conn_cnt_thresh, 0,
"How many connections (below) make us use the callout based mechanism");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, logging, CTLFLAG_RW,
&hpts_does_tp_logging, 0,
"Do we add to any tp that has logging on pacer logs");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, dyn_minsleep, CTLFLAG_RW,
&dynamic_min_sleep, 250,
"What is the dynamic minsleep value?");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, dyn_maxsleep, CTLFLAG_RW,
&dynamic_max_sleep, 5000,
"What is the dynamic maxsleep value?");
static int32_t max_pacer_loops = 10;
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, loopmax, CTLFLAG_RW,
&max_pacer_loops, 10,
"What is the maximum number of times the pacer will loop trying to catch up");
#define HPTS_MAX_SLEEP_ALLOWED (NUM_OF_HPTSI_SLOTS/2)
static uint32_t hpts_sleep_max = HPTS_MAX_SLEEP_ALLOWED;
static int
sysctl_net_inet_tcp_hpts_max_sleep(SYSCTL_HANDLER_ARGS)
{
int error;
uint32_t new;
new = hpts_sleep_max;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if ((new < (dynamic_min_sleep/HPTS_USECS_PER_SLOT)) ||
(new > HPTS_MAX_SLEEP_ALLOWED))
error = EINVAL;
else
hpts_sleep_max = new;
}
return (error);
}
static int
sysctl_net_inet_tcp_hpts_min_sleep(SYSCTL_HANDLER_ARGS)
{
int error;
uint32_t new;
new = tcp_min_hptsi_time;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if (new < LOWEST_SLEEP_ALLOWED)
error = EINVAL;
else
tcp_min_hptsi_time = new;
}
return (error);
}
SYSCTL_PROC(_net_inet_tcp_hpts, OID_AUTO, maxsleep,
CTLTYPE_UINT | CTLFLAG_RW,
&hpts_sleep_max, 0,
&sysctl_net_inet_tcp_hpts_max_sleep, "IU",
"Maximum time hpts will sleep in slots");
SYSCTL_PROC(_net_inet_tcp_hpts, OID_AUTO, minsleep,
CTLTYPE_UINT | CTLFLAG_RW,
&tcp_min_hptsi_time, 0,
&sysctl_net_inet_tcp_hpts_min_sleep, "IU",
"The minimum time the hpts must sleep before processing more slots");
static int slots_indicate_more_sleep = SLOTS_INDICATE_MORE_SLEEP;
static int slots_indicate_less_sleep = SLOTS_INDICATE_LESS_SLEEP;
static int tcp_hpts_no_wake_over_thresh = 1;
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, more_sleep, CTLFLAG_RW,
&slots_indicate_more_sleep, 0,
"If we only process this many or less on a timeout, we need longer sleep on the next callout");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, less_sleep, CTLFLAG_RW,
&slots_indicate_less_sleep, 0,
"If we process this many or more on a timeout, we need less sleep on the next callout");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, nowake_over_thresh, CTLFLAG_RW,
&tcp_hpts_no_wake_over_thresh, 0,
"When we are over the threshold on the pacer do we prohibit wakeups?");
uint16_t
tcp_hptsi_random_cpu(struct tcp_hptsi *pace)
{
uint16_t cpuid;
uint32_t ran;
ran = arc4random();
cpuid = (((ran & 0xffff) % mp_ncpus) % pace->rp_num_hptss);
return (cpuid);
}
static void
tcp_hpts_log(struct tcp_hpts_entry *hpts, struct tcpcb *tp, struct timeval *tv,
int slots_to_run, int idx, bool from_callout)
{
if (hpts_does_tp_logging && tcp_bblogging_on(tp)) {
union tcp_log_stackspecific log;
/*
* Unused logs are
* 64 bit - delRate, rttProp, bw_inuse
* 16 bit - cwnd_gain
* 8 bit - bbr_state, bbr_substate, inhpts;
*/
memset(&log, 0, sizeof(log));
log.u_bbr.flex1 = hpts->p_nxt_slot;
log.u_bbr.flex2 = hpts->p_cur_slot;
log.u_bbr.flex3 = hpts->p_prev_slot;
log.u_bbr.flex4 = idx;
log.u_bbr.flex6 = hpts->p_on_queue_cnt;
log.u_bbr.flex7 = hpts->p_cpu;
log.u_bbr.flex8 = (uint8_t)from_callout;
log.u_bbr.inflight = slots_to_run;
log.u_bbr.applimited = hpts->overidden_sleep;
log.u_bbr.timeStamp = tcp_tv_to_usec(tv);
log.u_bbr.epoch = hpts->saved_curslot;
log.u_bbr.lt_epoch = hpts->saved_prev_slot;
log.u_bbr.pkts_out = hpts->p_delayed_by;
log.u_bbr.lost = hpts->p_hpts_sleep_time;
log.u_bbr.pacing_gain = hpts->p_cpu;
log.u_bbr.pkt_epoch = hpts->p_runningslot;
log.u_bbr.use_lt_bw = 1;
TCP_LOG_EVENTP(tp, NULL,
&tptosocket(tp)->so_rcv,
&tptosocket(tp)->so_snd,
BBR_LOG_HPTSDIAG, 0,
0, &log, false, tv);
}
}
/*
* Timeout handler for the HPTS sleep callout. It immediately schedules the SWI
* for the HPTS entry to run.
*/
static void
tcp_hpts_sleep_timeout(void *arg)
{
#ifdef TCP_HPTS_KTEST
struct tcp_hptsi *pace;
#endif
struct tcp_hpts_entry *hpts;
hpts = (struct tcp_hpts_entry *)arg;
#ifdef TCP_HPTS_KTEST
pace = hpts->p_hptsi;
#endif
swi_sched(hpts->ie_cookie, 0);
}
/*
* Reset the HPTS callout timer with the provided timeval. Returns the results
* of the callout_reset_sbt_on() function.
*/
static int
tcp_hpts_sleep(struct tcp_hpts_entry *hpts, struct timeval *tv)
{
#ifdef TCP_HPTS_KTEST
struct tcp_hptsi *pace;
#endif
sbintime_t sb;
#ifdef TCP_HPTS_KTEST
pace = hpts->p_hptsi;
#endif
/* Store off to make visible the actual sleep time */
hpts->sleeping = tv->tv_usec;
sb = tvtosbt(*tv);
return (callout_reset_sbt_on(
&hpts->co, sb, 0, tcp_hpts_sleep_timeout, hpts, hpts->p_cpu,
(C_DIRECT_EXEC | C_PREL(tcp_hpts_precision))));
}
/*
* Schedules the SWI for the HTPS entry to run, if not already scheduled or
* running.
*/
void
tcp_hpts_wake(struct tcp_hpts_entry *hpts)
{
#ifdef TCP_HPTS_KTEST
struct tcp_hptsi *pace;
#endif
HPTS_MTX_ASSERT(hpts);
#ifdef TCP_HPTS_KTEST
pace = hpts->p_hptsi;
#endif
if (tcp_hpts_no_wake_over_thresh && (hpts->p_on_queue_cnt >= conn_cnt_thresh)) {
hpts->p_direct_wake = 0;
return;
}
if (hpts->p_hpts_wake_scheduled == 0) {
hpts->p_hpts_wake_scheduled = 1;
swi_sched(hpts->ie_cookie, 0);
}
}
static void
tcp_hpts_insert_internal(struct tcpcb *tp, struct tcp_hpts_entry *hpts)
{
struct inpcb *inp = tptoinpcb(tp);
struct hptsh *hptsh;
INP_WLOCK_ASSERT(inp);
HPTS_MTX_ASSERT(hpts);
MPASS(hpts->p_cpu == tp->t_hpts_cpu);
MPASS(!(tp->t_flags & TF_DISCONNECTED));
hptsh = &hpts->p_hptss[tp->t_hpts_slot];
if (tp->t_in_hpts == IHPTS_NONE) {
tp->t_in_hpts = IHPTS_ONQUEUE;
in_pcbref(inp);
} else if (tp->t_in_hpts == IHPTS_MOVING) {
tp->t_in_hpts = IHPTS_ONQUEUE;
} else
MPASS(tp->t_in_hpts == IHPTS_ONQUEUE);
tp->t_hpts_gencnt = hptsh->gencnt;
TAILQ_INSERT_TAIL(&hptsh->head, tp, t_hpts);
hptsh->count++;
hpts->p_on_queue_cnt++;
}
static struct tcp_hpts_entry *
tcp_hpts_lock(struct tcp_hptsi *pace, struct tcpcb *tp)
{
struct tcp_hpts_entry *hpts;
INP_LOCK_ASSERT(tptoinpcb(tp));
hpts = pace->rp_ent[tp->t_hpts_cpu];
HPTS_LOCK(hpts);
return (hpts);
}
static void
tcp_hpts_release(struct tcpcb *tp)
{
bool released __diagused;
tp->t_in_hpts = IHPTS_NONE;
released = in_pcbrele_wlocked(tptoinpcb(tp));
MPASS(released == false);
}
/*
* Initialize tcpcb to get ready for use with HPTS. We will know which CPU
* is preferred on the first incoming packet. Before that avoid crowding
* a single CPU with newborn connections and use a random one.
* This initialization is normally called on a newborn tcpcb, but potentially
* can be called once again if stack is switched. In that case we inherit CPU
* that the previous stack has set, be it random or not. In extreme cases,
* e.g. syzkaller fuzzing, a tcpcb can already be in HPTS in IHPTS_MOVING state
* and has never received a first packet.
*/
void
__tcp_hpts_init(struct tcp_hptsi *pace, struct tcpcb *tp)
{
if (__predict_true(tp->t_hpts_cpu == HPTS_CPU_NONE)) {
tp->t_hpts_cpu = tcp_hptsi_random_cpu(pace);
MPASS(!(tp->t_flags2 & TF2_HPTS_CPU_SET));
}
}
/*
* Called normally with the INP_LOCKED but it
* does not matter, the hpts lock is the key
* but the lock order allows us to hold the
* INP lock and then get the hpts lock.
*/
void
__tcp_hpts_remove(struct tcp_hptsi *pace, struct tcpcb *tp)
{
struct tcp_hpts_entry *hpts;
struct hptsh *hptsh;
INP_WLOCK_ASSERT(tptoinpcb(tp));
hpts = tcp_hpts_lock(pace, tp);
if (tp->t_in_hpts == IHPTS_ONQUEUE) {
hptsh = &hpts->p_hptss[tp->t_hpts_slot];
tp->t_hpts_request = 0;
if (__predict_true(tp->t_hpts_gencnt == hptsh->gencnt)) {
TAILQ_REMOVE(&hptsh->head, tp, t_hpts);
MPASS(hptsh->count > 0);
hptsh->count--;
MPASS(hpts->p_on_queue_cnt > 0);
hpts->p_on_queue_cnt--;
tcp_hpts_release(tp);
} else {
/*
* tcp_hptsi() now owns the TAILQ head of this inp.
* Can't TAILQ_REMOVE, just mark it.
*/
#ifdef INVARIANTS
struct tcpcb *tmp;
TAILQ_FOREACH(tmp, &hptsh->head, t_hpts)
MPASS(tmp != tp);
#endif
tp->t_in_hpts = IHPTS_MOVING;
tp->t_hpts_slot = -1;
}
} else if (tp->t_in_hpts == IHPTS_MOVING) {
/*
* Handle a special race condition:
* tcp_hptsi() moves inpcb to detached tailq
* tcp_hpts_remove() marks as IHPTS_MOVING, slot = -1
* tcp_hpts_insert() sets slot to a meaningful value
* The connection is terminated with the final call to
tcp_hpts_remove() again (we are here!) and we fail to call
tcp_hpts_release() since it is IHPTS_MOVING. Set slot to -1
to delegate the release to the owner of the detached tailq.
*/
tp->t_hpts_slot = -1;
}
HPTS_UNLOCK(hpts);
}
static inline int
hpts_slot(uint32_t wheel_slot, uint32_t plus)
{
/*
* Given a slot on the wheel, what slot
* is that plus slots out?
*/
KASSERT(wheel_slot < NUM_OF_HPTSI_SLOTS, ("Invalid slot %u not on wheel", wheel_slot));
return ((wheel_slot + plus) % NUM_OF_HPTSI_SLOTS);
}
static inline int
cts_to_wheel(uint32_t cts)
{
/*
* Given a timestamp in useconds map it to our limited space wheel.
*/
return ((cts / HPTS_USECS_PER_SLOT) % NUM_OF_HPTSI_SLOTS);
}
static inline int
hpts_slots_diff(int prev_slot, int slot_now)
{
/*
* Given two slots that are someplace
* on our wheel. How far are they apart?
*/
if (slot_now > prev_slot)
return (slot_now - prev_slot);
else if (slot_now == prev_slot)
/*
* Special case, same means we can go all of our
* wheel less one slot.
*/
return (NUM_OF_HPTSI_SLOTS - 1);
else
return ((NUM_OF_HPTSI_SLOTS - prev_slot) + slot_now);
}
/*
* Given a slot on the wheel that is the current time
* mapped to the wheel (wheel_slot), what is the maximum
* distance forward that can be obtained without
* wrapping past either prev_slot or running_slot
* depending on the htps state? Also if passed
* a uint32_t *, fill it with the slot location.
*
* Note if you do not give this function the current
* time (that you think it is) mapped to the wheel slot
* then the results will not be what you expect and
* could lead to invalid inserts.
*/
static inline int32_t
max_slots_available(struct tcp_hpts_entry *hpts, uint32_t wheel_slot, uint32_t *target_slot)
{
uint32_t dis_to_travel, end_slot, pacer_to_now, avail_on_wheel;
if ((hpts->p_hpts_active == 1) &&
(hpts->p_wheel_complete == 0)) {
end_slot = hpts->p_runningslot;
/* Back up one slot */
if (end_slot == 0)
end_slot = NUM_OF_HPTSI_SLOTS - 1;
else
end_slot--;
if (target_slot)
*target_slot = end_slot;
} else {
/*
* For the case where we are
* not active, or we have
* completed the pass over
* the wheel, we can use the
* prev slot and subtract one from it. This puts us
* as far out as possible on the wheel.
*/
end_slot = hpts->p_prev_slot;
if (end_slot == 0)
end_slot = NUM_OF_HPTSI_SLOTS - 1;
else
end_slot--;
if (target_slot)
*target_slot = end_slot;
/*
* Now we have close to the full wheel left minus the
* time it has been since the pacer went to sleep. Note
* that wheel_slot, passed in, should be the current time
* from the perspective of the caller, mapped to the wheel.
*/
if (hpts->p_prev_slot != wheel_slot)
dis_to_travel = hpts_slots_diff(hpts->p_prev_slot, wheel_slot);
else
dis_to_travel = 1;
/*
* dis_to_travel in this case is the space from when the
* pacer stopped (p_prev_slot) and where our wheel_slot
* is now. To know how many slots we can put it in we
* subtract from the wheel size. We would not want
* to place something after p_prev_slot or it will
* get ran too soon.
*/
return (NUM_OF_HPTSI_SLOTS - dis_to_travel);
}
/*
* So how many slots are open between p_runningslot -> p_cur_slot
* that is what is currently un-available for insertion. Special
* case when we are at the last slot, this gets 1, so that
* the answer to how many slots are available is all but 1.
*/
if (hpts->p_runningslot == hpts->p_cur_slot)
dis_to_travel = 1;
else
dis_to_travel = hpts_slots_diff(hpts->p_runningslot, hpts->p_cur_slot);
/*
* How long has the pacer been running?
*/
if (hpts->p_cur_slot != wheel_slot) {
/* The pacer is a bit late */
pacer_to_now = hpts_slots_diff(hpts->p_cur_slot, wheel_slot);
} else {
/* The pacer is right on time, now == pacers start time */
pacer_to_now = 0;
}
/*
* To get the number left we can insert into we simply
* subtract the distance the pacer has to run from how
* many slots there are.
*/
avail_on_wheel = NUM_OF_HPTSI_SLOTS - dis_to_travel;
/*
* Now how many of those we will eat due to the pacer's
* time (p_cur_slot) of start being behind the
* real time (wheel_slot)?
*/
if (avail_on_wheel <= pacer_to_now) {
/*
* Wheel wrap, we can't fit on the wheel, that
* is unusual the system must be way overloaded!
* Insert into the assured slot, and return special
* "0".
*/
counter_u64_add(combined_wheel_wrap, 1);
if (target_slot)
*target_slot = hpts->p_nxt_slot;
return (0);
} else {
/*
* We know how many slots are open
* on the wheel (the reverse of what
* is left to run. Take away the time
* the pacer started to now (wheel_slot)
* and that tells you how many slots are
* open that can be inserted into that won't
* be touched by the pacer until later.
*/
return (avail_on_wheel - pacer_to_now);
}
}
#ifdef INVARIANTS
static void
check_if_slot_would_be_wrong(struct tcp_hpts_entry *hpts, struct tcpcb *tp,
uint32_t hptsslot)
{
/*
* Sanity checks for the pacer with invariants
* on insert.
*/
KASSERT(hptsslot < NUM_OF_HPTSI_SLOTS,
("hpts:%p tp:%p slot:%d > max", hpts, tp, hptsslot));
if ((hpts->p_hpts_active) &&
(hpts->p_wheel_complete == 0)) {
/*
* If the pacer is processing a arc
* of the wheel, we need to make
* sure we are not inserting within
* that arc.
*/
int distance, yet_to_run;
distance = hpts_slots_diff(hpts->p_runningslot, hptsslot);
if (hpts->p_runningslot != hpts->p_cur_slot)
yet_to_run = hpts_slots_diff(hpts->p_runningslot, hpts->p_cur_slot);
else
yet_to_run = 0; /* processing last slot */
KASSERT(yet_to_run <= distance, ("hpts:%p tp:%p slot:%d "
"distance:%d yet_to_run:%d rs:%d cs:%d", hpts, tp,
hptsslot, distance, yet_to_run, hpts->p_runningslot,
hpts->p_cur_slot));
}
}
#endif
void
__tcp_hpts_insert(struct tcp_hptsi *pace, struct tcpcb *tp, uint32_t usecs,
struct hpts_diag *diag)
{
struct tcp_hpts_entry *hpts;
struct timeval tv;
uint32_t slot, wheel_cts, last_slot, need_new_to = 0;
int32_t wheel_slot, maxslots;
bool need_wakeup = false;
INP_WLOCK_ASSERT(tptoinpcb(tp));
MPASS(!(tp->t_flags & TF_DISCONNECTED));
MPASS(!(tp->t_in_hpts == IHPTS_ONQUEUE));
/*
* Convert microseconds to slots for internal use.
* We now return the next-slot the hpts will be on, beyond its
* current run (if up) or where it was when it stopped if it is
* sleeping.
*/
slot = HPTS_USEC_TO_SLOTS(usecs);
hpts = tcp_hpts_lock(pace, tp);
microuptime(&tv);
if (diag) {
memset(diag, 0, sizeof(struct hpts_diag));
diag->p_hpts_active = hpts->p_hpts_active;
diag->p_prev_slot = hpts->p_prev_slot;
diag->p_runningslot = hpts->p_runningslot;
diag->p_nxt_slot = hpts->p_nxt_slot;
diag->p_cur_slot = hpts->p_cur_slot;
diag->slot_req = slot;
diag->p_on_min_sleep = hpts->p_on_min_sleep;
diag->hpts_sleep_time = hpts->p_hpts_sleep_time;
}
if (slot == 0) {
/* Ok we need to set it on the hpts in the current slot */
tp->t_hpts_request = 0;
if ((hpts->p_hpts_active == 0) || (hpts->p_wheel_complete)) {
/*
* A sleeping hpts we want in next slot to run
* note that in this state p_prev_slot == p_cur_slot
*/
tp->t_hpts_slot = hpts_slot(hpts->p_prev_slot, 1);
if ((hpts->p_on_min_sleep == 0) &&
(hpts->p_hpts_active == 0))
need_wakeup = true;
} else
tp->t_hpts_slot = hpts->p_runningslot;
if (__predict_true(tp->t_in_hpts != IHPTS_MOVING))
tcp_hpts_insert_internal(tp, hpts);
if (need_wakeup) {
/*
* Activate the hpts if it is sleeping and its
* timeout is not 1.
*/
hpts->p_direct_wake = 1;
tcp_hpts_wake(hpts);
}
HPTS_UNLOCK(hpts);
return;
}
/* Get the current time stamp and map it onto the wheel */
wheel_cts = tcp_tv_to_usec(&tv);
wheel_slot = cts_to_wheel(wheel_cts);
/* Now what's the max we can place it at? */
maxslots = max_slots_available(hpts, wheel_slot, &last_slot);
if (diag) {
diag->wheel_slot = wheel_slot;
diag->maxslots = maxslots;
diag->wheel_cts = wheel_cts;
}
if (maxslots == 0) {
/* The pacer is in a wheel wrap behind, yikes! */
if (slot > 1) {
/*
* Reduce by 1 to prevent a forever loop in
* case something else is wrong. Note this
* probably does not hurt because the pacer
* if its true is so far behind we will be
* > 1second late calling anyway.
*/
slot--;
}
tp->t_hpts_slot = last_slot;
tp->t_hpts_request = slot;
} else if (maxslots >= slot) {
/* It all fits on the wheel */
tp->t_hpts_request = 0;
tp->t_hpts_slot = hpts_slot(wheel_slot, slot);
} else {
/* It does not fit */
tp->t_hpts_request = slot - maxslots;
tp->t_hpts_slot = last_slot;
}
if (diag) {
diag->time_remaining = tp->t_hpts_request;
diag->inp_hptsslot = tp->t_hpts_slot;
}
#ifdef INVARIANTS
check_if_slot_would_be_wrong(hpts, tp, tp->t_hpts_slot);
#endif
if (__predict_true(tp->t_in_hpts != IHPTS_MOVING))
tcp_hpts_insert_internal(tp, hpts);
if ((hpts->p_hpts_active == 0) &&
(tp->t_hpts_request == 0) &&
(hpts->p_on_min_sleep == 0)) {
/*
* The hpts is sleeping and NOT on a minimum
* sleep time, we need to figure out where
* it will wake up at and if we need to reschedule
* its time-out.
*/
uint32_t have_slept, yet_to_sleep;
/* Now do we need to restart the hpts's timer? */
have_slept = hpts_slots_diff(hpts->p_prev_slot, wheel_slot);
if (have_slept < hpts->p_hpts_sleep_time)
yet_to_sleep = hpts->p_hpts_sleep_time - have_slept;
else {
/* We are over-due */
yet_to_sleep = 0;
need_wakeup = 1;
}
if (diag) {
diag->have_slept = have_slept;
diag->yet_to_sleep = yet_to_sleep;
}
if (yet_to_sleep &&
(yet_to_sleep > slot)) {
/*
* We need to reschedule the hpts's time-out.
*/
hpts->p_hpts_sleep_time = slot;
need_new_to = slot * HPTS_USECS_PER_SLOT;
}
}
/*
* Now how far is the hpts sleeping to? if active is 1, its
* up and running we do nothing, otherwise we may need to
* reschedule its callout if need_new_to is set from above.
*/
if (need_wakeup) {
hpts->p_direct_wake = 1;
tcp_hpts_wake(hpts);
if (diag) {
diag->need_new_to = 0;
diag->co_ret = 0xffff0000;
}
} else if (need_new_to) {
int32_t co_ret;
struct timeval tv;
tv.tv_sec = 0;
tv.tv_usec = 0;
while (need_new_to > HPTS_USEC_IN_SEC) {
tv.tv_sec++;
need_new_to -= HPTS_USEC_IN_SEC;
}
tv.tv_usec = need_new_to; /* XXX: Why is this sleeping over the max? */
co_ret = tcp_hpts_sleep(hpts, &tv);
if (diag) {
diag->need_new_to = need_new_to;
diag->co_ret = co_ret;
}
}
HPTS_UNLOCK(hpts);
}
static uint16_t
hpts_cpuid(struct tcp_hptsi *pace, struct tcpcb *tp, int *failed)
{
struct inpcb *inp = tptoinpcb(tp);
u_int cpuid;
#ifdef NUMA
struct hpts_domain_info *di;
#endif
*failed = 0;
if (tp->t_flags2 & TF2_HPTS_CPU_SET) {
return (tp->t_hpts_cpu);
}
/*
* If we are using the irq cpu set by LRO or
* the driver then it overrides all other domains.
*/
if (tcp_use_irq_cpu) {
if (tp->t_lro_cpu == HPTS_CPU_NONE) {
*failed = 1;
return (0);
}
return (tp->t_lro_cpu);
}
/* If one is set the other must be the same */
#ifdef RSS
cpuid = rss_hash2cpuid(inp->inp_flowid, inp->inp_flowtype);
if (cpuid == NETISR_CPUID_NONE)
return (tcp_hptsi_random_cpu(pace));
else
return (cpuid);
#endif
/*
* We don't have a flowid -> cpuid mapping, so cheat and just map
* unknown cpuids to curcpu. Not the best, but apparently better
* than defaulting to swi 0.
*/
if (inp->inp_flowtype == M_HASHTYPE_NONE) {
counter_u64_add(cpu_uses_random, 1);
return (tcp_hptsi_random_cpu(pace));
}
/*
* Hash to a thread based on the flowid. If we are using numa,
* then restrict the hash to the numa domain where the inp lives.
*/
#ifdef NUMA
if ((vm_ndomains == 1) ||
(inp->inp_numa_domain == M_NODOM)) {
#endif
cpuid = inp->inp_flowid % mp_ncpus;
#ifdef NUMA
} else {
/* Hash into the cpu's that use that domain */
di = &pace->domains[inp->inp_numa_domain];
cpuid = di->cpu[inp->inp_flowid % di->count];
}
#endif
counter_u64_add(cpu_uses_flowid, 1);
return (cpuid);
}
static void
tcp_hpts_set_max_sleep(struct tcp_hpts_entry *hpts, int wrap_loop_cnt)
{
uint32_t t = 0, i;
if ((hpts->p_on_queue_cnt) && (wrap_loop_cnt < 2)) {
/*
* Find next slot that is occupied and use that to
* be the sleep time.
*/
for (i = 0, t = hpts_slot(hpts->p_cur_slot, 1); i < NUM_OF_HPTSI_SLOTS; i++) {
if (TAILQ_EMPTY(&hpts->p_hptss[t].head) == 0) {
break;
}
t = (t + 1) % NUM_OF_HPTSI_SLOTS;
}
KASSERT((i != NUM_OF_HPTSI_SLOTS), ("Hpts:%p cnt:%d but none found", hpts, hpts->p_on_queue_cnt));
hpts->p_hpts_sleep_time = min((i + 1), hpts_sleep_max);
} else {
/* No one on the wheel sleep for all but 400 slots or sleep max */
hpts->p_hpts_sleep_time = hpts_sleep_max;
}
}
static bool
tcp_hpts_different_slots(uint32_t cts, uint32_t cts_last_run)
{
return ((cts / HPTS_USECS_PER_SLOT) != (cts_last_run / HPTS_USECS_PER_SLOT));
}
int32_t
tcp_hptsi(struct tcp_hpts_entry *hpts, bool from_callout)
{
struct tcp_hptsi *pace;
struct tcpcb *tp;
struct timeval tv;
int32_t slots_to_run, i, error;
int32_t loop_cnt = 0;
int32_t did_prefetch = 0;
int32_t prefetch_tp = 0;
int32_t wrap_loop_cnt = 0;
int32_t slot_pos_of_endpoint = 0;
int32_t orig_exit_slot;
uint32_t cts, cts_last_run;
bool completed_measure, seen_endpoint;
completed_measure = false;
seen_endpoint = false;
HPTS_MTX_ASSERT(hpts);
NET_EPOCH_ASSERT();
pace = hpts->p_hptsi;
MPASS(pace != NULL);
/* record previous info for any logging */
hpts->saved_curslot = hpts->p_cur_slot;
hpts->saved_prev_slot = hpts->p_prev_slot;
microuptime(&tv);
cts_last_run = pace->cts_last_ran[hpts->p_cpu];
pace->cts_last_ran[hpts->p_cpu] = cts = tcp_tv_to_usec(&tv);
orig_exit_slot = hpts->p_cur_slot = cts_to_wheel(cts);
if ((hpts->p_on_queue_cnt == 0) ||
!tcp_hpts_different_slots(cts, cts_last_run)) {
/*
* Not enough time has yet passed or nothing to do.
*/
hpts->p_prev_slot = hpts->p_cur_slot;
goto no_run;
}
again:
hpts->p_wheel_complete = 0;
HPTS_MTX_ASSERT(hpts);
slots_to_run = hpts_slots_diff(hpts->p_prev_slot, hpts->p_cur_slot);
if ((hpts->p_on_queue_cnt != 0) &&
((cts - cts_last_run) >
((NUM_OF_HPTSI_SLOTS-1) * HPTS_USECS_PER_SLOT))) {
/*
* Wheel wrap is occuring, basically we
* are behind and the distance between
* run's has spread so much it has exceeded
* the time on the wheel (1.024 seconds). This
* is ugly and should NOT be happening. We
* need to run the entire wheel. We last processed
* p_prev_slot, so that needs to be the last slot
* we run. The next slot after that should be our
* reserved first slot for new, and then starts
* the running position. Now the problem is the
* reserved "not to yet" place does not exist
* and there may be inp's in there that need
* running. We can merge those into the
* first slot at the head.
*/
wrap_loop_cnt++;
hpts->p_nxt_slot = hpts_slot(hpts->p_prev_slot, 1);
hpts->p_runningslot = hpts_slot(hpts->p_prev_slot, 2);
/*
* Adjust p_cur_slot to be where we are starting from
* hopefully we will catch up (fat chance if something
* is broken this bad :( )
*/
hpts->p_cur_slot = hpts->p_prev_slot;
/*
* The next slot has guys to run too, and that would
* be where we would normally start, lets move them into
* the next slot (p_prev_slot + 2) so that we will
* run them, the extra 10usecs of late (by being
* put behind) does not really matter in this situation.
*/
TAILQ_FOREACH(tp, &hpts->p_hptss[hpts->p_nxt_slot].head,
t_hpts) {
MPASS(tp->t_hpts_slot == hpts->p_nxt_slot);
MPASS(tp->t_hpts_gencnt ==
hpts->p_hptss[hpts->p_nxt_slot].gencnt);
MPASS(tp->t_in_hpts == IHPTS_ONQUEUE);
/*
* Update gencnt and nextslot accordingly to match
* the new location. This is safe since it takes both
* the INP lock and the pacer mutex to change the
* t_hptsslot and t_hpts_gencnt.
*/
tp->t_hpts_gencnt =
hpts->p_hptss[hpts->p_runningslot].gencnt;
tp->t_hpts_slot = hpts->p_runningslot;
}
TAILQ_CONCAT(&hpts->p_hptss[hpts->p_runningslot].head,
&hpts->p_hptss[hpts->p_nxt_slot].head, t_hpts);
hpts->p_hptss[hpts->p_runningslot].count +=
hpts->p_hptss[hpts->p_nxt_slot].count;
hpts->p_hptss[hpts->p_nxt_slot].count = 0;
hpts->p_hptss[hpts->p_nxt_slot].gencnt++;
slots_to_run = NUM_OF_HPTSI_SLOTS - 1;
counter_u64_add(wheel_wrap, 1);
} else {
/*
* Nxt slot is always one after p_runningslot though
* its not used usually unless we are doing wheel wrap.
*/
hpts->p_nxt_slot = hpts->p_prev_slot;
hpts->p_runningslot = hpts_slot(hpts->p_prev_slot, 1);
}
if (hpts->p_on_queue_cnt == 0) {
goto no_one;
}
for (i = 0; i < slots_to_run; i++) {
struct tcpcb *tp, *ntp;
TAILQ_HEAD(, tcpcb) head = TAILQ_HEAD_INITIALIZER(head);
struct hptsh *hptsh;
uint32_t runningslot;
/*
* Calculate our delay, if there are no extra slots there
* was not any (i.e. if slots_to_run == 1, no delay).
*/
hpts->p_delayed_by = (slots_to_run - (i + 1)) *
HPTS_USECS_PER_SLOT;
runningslot = hpts->p_runningslot;
hptsh = &hpts->p_hptss[runningslot];
TAILQ_SWAP(&head, &hptsh->head, tcpcb, t_hpts);
hpts->p_on_queue_cnt -= hptsh->count;
hptsh->count = 0;
hptsh->gencnt++;
HPTS_UNLOCK(hpts);
TAILQ_FOREACH_SAFE(tp, &head, t_hpts, ntp) {
struct inpcb *inp = tptoinpcb(tp);
bool set_cpu;
if (ntp != NULL) {
/*
* If we have a next tcpcb, see if we can
* prefetch it. Note this may seem
* "risky" since we have no locks (other
* than the previous inp) and there no
* assurance that ntp was not pulled while
* we were processing tp and freed. If this
* occurred it could mean that either:
*
* a) Its NULL (which is fine we won't go
* here) <or> b) Its valid (which is cool we
* will prefetch it) <or> c) The inp got
* freed back to the slab which was
* reallocated. Then the piece of memory was
* re-used and something else (not an
* address) is in inp_ppcb. If that occurs
* we don't crash, but take a TLB shootdown
* performance hit (same as if it was NULL
* and we tried to pre-fetch it).
*
* Considering that the likelyhood of <c> is
* quite rare we will take a risk on doing
* this. If performance drops after testing
* we can always take this out. NB: the
* kern_prefetch on amd64 actually has
* protection against a bad address now via
* the DMAP_() tests. This will prevent the
* TLB hit, and instead if <c> occurs just
* cause us to load cache with a useless
* address (to us).
*
* XXXGL: this comment and the prefetch action
* could be outdated after tp == inp change.
*/
kern_prefetch(ntp, &prefetch_tp);
prefetch_tp = 1;
}
/* For debugging */
if (!seen_endpoint) {
seen_endpoint = true;
orig_exit_slot = slot_pos_of_endpoint =
runningslot;
} else if (!completed_measure) {
/* Record the new position */
orig_exit_slot = runningslot;
}
INP_WLOCK(inp);
if ((tp->t_flags2 & TF2_HPTS_CPU_SET) == 0) {
set_cpu = true;
} else {
set_cpu = false;
}
if (__predict_false(tp->t_in_hpts == IHPTS_MOVING)) {
if (tp->t_hpts_slot == -1) {
tp->t_in_hpts = IHPTS_NONE;
if (in_pcbrele_wlocked(inp) == false)
INP_WUNLOCK(inp);
} else {
HPTS_LOCK(hpts);
tcp_hpts_insert_internal(tp, hpts);
HPTS_UNLOCK(hpts);
INP_WUNLOCK(inp);
}
continue;
}
MPASS(tp->t_in_hpts == IHPTS_ONQUEUE);
MPASS(!(tp->t_flags & TF_DISCONNECTED));
KASSERT(runningslot == tp->t_hpts_slot,
("Hpts:%p inp:%p slot mis-aligned %u vs %u",
hpts, inp, runningslot, tp->t_hpts_slot));
if (tp->t_hpts_request) {
/*
* This guy is deferred out further in time
* then our wheel had available on it.
* Push him back on the wheel or run it
* depending.
*/
uint32_t maxslots, last_slot, remaining_slots;
remaining_slots = slots_to_run - (i + 1);
if (tp->t_hpts_request > remaining_slots) {
HPTS_LOCK(hpts);
/*
* How far out can we go?
*/
maxslots = max_slots_available(hpts,
hpts->p_cur_slot, &last_slot);
if (maxslots >= tp->t_hpts_request) {
/* We can place it finally to
* be processed. */
tp->t_hpts_slot = hpts_slot(
hpts->p_runningslot,
tp->t_hpts_request);
tp->t_hpts_request = 0;
} else {
/* Work off some more time */
tp->t_hpts_slot = last_slot;
tp->t_hpts_request -=
maxslots;
}
tcp_hpts_insert_internal(tp, hpts);
HPTS_UNLOCK(hpts);
INP_WUNLOCK(inp);
continue;
}
tp->t_hpts_request = 0;
/* Fall through we will so do it now */
}
tcp_hpts_release(tp);
if (set_cpu) {
/*
* Setup so the next time we will move to
* the right CPU. This should be a rare
* event. It will sometimes happens when we
* are the client side (usually not the
* server). Somehow tcp_output() gets called
* before the tcp_do_segment() sets the
* intial state. This means the r_cpu and
* r_hpts_cpu is 0. We get on the hpts, and
* then tcp_input() gets called setting up
* the r_cpu to the correct value. The hpts
* goes off and sees the mis-match. We
* simply correct it here and the CPU will
* switch to the new hpts nextime the tcb
* gets added to the hpts (not this one)
* :-)
*/
__tcp_set_hpts(pace, tp);
}
CURVNET_SET(inp->inp_socket->so_vnet);
/* Lets do any logging that we might want to */
tcp_hpts_log(hpts, tp, &tv, slots_to_run, i, from_callout);
if (tp->t_fb_ptr != NULL) {
kern_prefetch(tp->t_fb_ptr, &did_prefetch);
did_prefetch = 1;
}
/*
* We set TF2_HPTS_CALLS before any possible output.
* The contract with the transport is that if it cares
* about hpts calling it should clear the flag. That
* way next time it is called it will know it is hpts.
*
* We also only call tfb_do_queued_segments() <or>
* tcp_output(). It is expected that if segments are
* queued and come in that the final input mbuf will
* cause a call to output if it is needed so we do
* not need a second call to tcp_output(). So we do
* one or the other but not both.
*
* XXXGL: some KPI abuse here. tfb_do_queued_segments
* returns unlocked with positive error (always 1) and
* tcp_output returns unlocked with negative error.
*/
tp->t_flags2 |= TF2_HPTS_CALLS;
if ((tp->t_flags2 & TF2_SUPPORTS_MBUFQ) &&
!STAILQ_EMPTY(&tp->t_inqueue))
error = -(*tp->t_fb->tfb_do_queued_segments)(tp,
0);
else
error = tcp_output(tp);
if (__predict_true(error >= 0))
INP_WUNLOCK(inp);
CURVNET_RESTORE();
}
if (seen_endpoint) {
/*
* We now have a accurate distance between
* slot_pos_of_endpoint <-> orig_exit_slot
* to tell us how late we were, orig_exit_slot
* is where we calculated the end of our cycle to
* be when we first entered.
*/
completed_measure = true;
}
HPTS_LOCK(hpts);
hpts->p_runningslot++;
if (hpts->p_runningslot >= NUM_OF_HPTSI_SLOTS) {
hpts->p_runningslot = 0;
}
}
no_one:
HPTS_MTX_ASSERT(hpts);
hpts->p_delayed_by = 0;
/*
* Check to see if we took an excess amount of time and need to run
* more slots (if we did not hit eno-bufs).
*/
hpts->p_prev_slot = hpts->p_cur_slot;
microuptime(&tv);
cts_last_run = cts;
cts = tcp_tv_to_usec(&tv);
if (!from_callout || (loop_cnt > max_pacer_loops)) {
/*
* Something is serious slow we have
* looped through processing the wheel
* and by the time we cleared the
* needs to run max_pacer_loops time
* we still needed to run. That means
* the system is hopelessly behind and
* can never catch up :(
*
* We will just lie to this thread
* and let it think p_curslot is
* correct. When it next awakens
* it will find itself further behind.
*/
if (from_callout)
counter_u64_add(hpts_hopelessly_behind, 1);
goto no_run;
}
hpts->p_cur_slot = cts_to_wheel(cts);
if (!seen_endpoint) {
/* We saw no endpoint but we may be looping */
orig_exit_slot = hpts->p_cur_slot;
}
if ((wrap_loop_cnt < 2) && tcp_hpts_different_slots(cts, cts_last_run)) {
counter_u64_add(hpts_loops, 1);
loop_cnt++;
goto again;
}
no_run:
pace->cts_last_ran[hpts->p_cpu] = cts;
/*
* Set flag to tell that we are done for
* any slot input that happens during
* input.
*/
hpts->p_wheel_complete = 1;
/*
* If enough time has elapsed that we should be processing the next
* slot(s), then we should have kept running and not marked the wheel as
* complete.
*
* But there are several other conditions where we would have stopped
* processing, so the prev/cur slots and cts variables won't match.
* These conditions are:
*
* - Calls not from callouts don't run multiple times
* - The wheel is empty
* - We've processed more than max_pacer_loops times
* - We've wrapped more than 2 times
*
* This assert catches when the logic above has violated this design.
*
*/
KASSERT((!from_callout || (hpts->p_on_queue_cnt == 0) ||
(loop_cnt > max_pacer_loops) || (wrap_loop_cnt >= 2) ||
((hpts->p_prev_slot == hpts->p_cur_slot) &&
!tcp_hpts_different_slots(cts, cts_last_run))),
("H:%p Shouldn't be done! prev_slot:%u, cur_slot:%u, "
"cts_last_run:%u, cts:%u, loop_cnt:%d, wrap_loop_cnt:%d",
hpts, hpts->p_prev_slot, hpts->p_cur_slot,
cts_last_run, cts, loop_cnt, wrap_loop_cnt));
if (from_callout && tcp_hpts_different_slots(cts, cts_last_run)) {
microuptime(&tv);
cts = tcp_tv_to_usec(&tv);
hpts->p_cur_slot = cts_to_wheel(cts);
counter_u64_add(hpts_loops, 1);
goto again;
}
if (from_callout) {
tcp_hpts_set_max_sleep(hpts, wrap_loop_cnt);
}
if (seen_endpoint)
return(hpts_slots_diff(slot_pos_of_endpoint, orig_exit_slot));
else
return (0);
}
void
__tcp_set_hpts(struct tcp_hptsi *pace, struct tcpcb *tp)
{
struct tcp_hpts_entry *hpts;
int failed;
INP_WLOCK_ASSERT(tptoinpcb(tp));
hpts = tcp_hpts_lock(pace, tp);
if (tp->t_in_hpts == IHPTS_NONE && !(tp->t_flags2 & TF2_HPTS_CPU_SET)) {
tp->t_hpts_cpu = hpts_cpuid(pace, tp, &failed);
if (failed == 0)
tp->t_flags2 |= TF2_HPTS_CPU_SET;
}
HPTS_UNLOCK(hpts);
}
static struct tcp_hpts_entry *
tcp_choose_hpts_to_run(struct tcp_hptsi *pace)
{
struct timeval tv;
int i, oldest_idx, start, end;
uint32_t cts, time_since_ran, calc;
microuptime(&tv);
cts = tcp_tv_to_usec(&tv);
time_since_ran = 0;
/* Default is all one group */
start = 0;
end = pace->rp_num_hptss;
/*
* If we have more than one L3 group figure out which one
* this CPU is in.
*/
if (pace->grp_cnt > 1) {
for (i = 0; i < pace->grp_cnt; i++) {
if (CPU_ISSET(curcpu, &pace->grps[i]->cg_mask)) {
start = pace->grps[i]->cg_first;
end = (pace->grps[i]->cg_last + 1);
break;
}
}
}
oldest_idx = -1;
for (i = start; i < end; i++) {
if (TSTMP_GT(cts, pace->cts_last_ran[i]))
calc = cts - pace->cts_last_ran[i];
else
calc = 0;
if (calc > time_since_ran) {
oldest_idx = i;
time_since_ran = calc;
}
}
if (oldest_idx >= 0)
return(pace->rp_ent[oldest_idx]);
else
return(pace->rp_ent[(curcpu % pace->rp_num_hptss)]);
}
void
_tcp_hpts_softclock(void)
{
struct epoch_tracker et;
struct tcp_hpts_entry *hpts;
int slots_ran;
if (hpts_that_need_softclock == 0)
return;
hpts = tcp_choose_hpts_to_run(tcp_hptsi_pace);
if (hpts->p_hpts_active) {
/* Already active */
return;
}
if (!HPTS_TRYLOCK(hpts)) {
/* Someone else got the lock */
return;
}
NET_EPOCH_ENTER(et);
if (hpts->p_hpts_active)
goto out_with_mtx;
hpts->syscall_cnt++;
counter_u64_add(hpts_direct_call, 1);
hpts->p_hpts_active = 1;
slots_ran = tcp_hptsi(hpts, false);
/* We may want to adjust the sleep values here */
if (hpts->p_on_queue_cnt >= conn_cnt_thresh) {
if (slots_ran > slots_indicate_less_sleep) {
struct timeval tv;
hpts->p_mysleep.tv_usec /= 2;
if (hpts->p_mysleep.tv_usec < dynamic_min_sleep)
hpts->p_mysleep.tv_usec = dynamic_min_sleep;
/* Reschedule with new to value */
tcp_hpts_set_max_sleep(hpts, 0);
tv.tv_sec = 0;
tv.tv_usec = hpts->p_hpts_sleep_time * HPTS_USECS_PER_SLOT;
/* Validate its in the right ranges */
if (tv.tv_usec < hpts->p_mysleep.tv_usec) {
hpts->overidden_sleep = tv.tv_usec;
tv.tv_usec = hpts->p_mysleep.tv_usec;
} else if (tv.tv_usec > dynamic_max_sleep) {
/* Lets not let sleep get above this value */
hpts->overidden_sleep = tv.tv_usec;
tv.tv_usec = dynamic_max_sleep;
}
/*
* In this mode the timer is a backstop to
* all the lro_flushes so we use
* the dynamic value and set the on_min_sleep
* flag so we will not be awoken.
*/
(void)tcp_hpts_sleep(hpts, &tv);
} else if (slots_ran < slots_indicate_more_sleep) {
/* For the further sleep, don't reschedule hpts */
hpts->p_mysleep.tv_usec *= 2;
if (hpts->p_mysleep.tv_usec > dynamic_max_sleep)
hpts->p_mysleep.tv_usec = dynamic_max_sleep;
}
hpts->p_on_min_sleep = 1;
}
hpts->p_hpts_active = 0;
out_with_mtx:
HPTS_UNLOCK(hpts);
NET_EPOCH_EXIT(et);
}
static void
tcp_hpts_thread(void *ctx)
{
#ifdef TCP_HPTS_KTEST
struct tcp_hptsi *pace;
#endif
struct tcp_hpts_entry *hpts;
struct epoch_tracker et;
struct timeval tv;
int slots_ran;
hpts = (struct tcp_hpts_entry *)ctx;
#ifdef TCP_HPTS_KTEST
pace = hpts->p_hptsi;
#endif
HPTS_LOCK(hpts);
if (hpts->p_direct_wake) {
/* Signaled by input or output with low occupancy count. */
_callout_stop_safe(&hpts->co, 0);
counter_u64_add(hpts_direct_awakening, 1);
} else {
/* Timed out, the normal case. */
counter_u64_add(hpts_wake_timeout, 1);
if (callout_pending(&hpts->co) ||
!callout_active(&hpts->co)) {
HPTS_UNLOCK(hpts);
return;
}
}
callout_deactivate(&hpts->co);
hpts->p_hpts_wake_scheduled = 0;
NET_EPOCH_ENTER(et);
if (hpts->p_hpts_active) {
/*
* We are active already. This means that a syscall
* trap or LRO is running in behalf of hpts. In that case
* we need to double our timeout since there seems to be
* enough activity in the system that we don't need to
* run as often (if we were not directly woken).
*/
tv.tv_sec = 0;
if (hpts->p_direct_wake == 0) {
counter_u64_add(hpts_back_tosleep, 1);
if (hpts->p_on_queue_cnt >= conn_cnt_thresh) {
hpts->p_mysleep.tv_usec *= 2;
if (hpts->p_mysleep.tv_usec > dynamic_max_sleep)
hpts->p_mysleep.tv_usec = dynamic_max_sleep;
tv.tv_usec = hpts->p_mysleep.tv_usec;
hpts->p_on_min_sleep = 1;
} else {
/*
* Here we have low count on the wheel, but
* somehow we still collided with one of the
* connections. Lets go back to sleep for a
* min sleep time, but clear the flag so we
* can be awoken by insert.
*/
hpts->p_on_min_sleep = 0;
tv.tv_usec = tcp_min_hptsi_time;
}
} else {
/*
* Directly woken most likely to reset the
* callout time.
*/
tv.tv_usec = hpts->p_mysleep.tv_usec;
}
goto back_to_sleep;
}
hpts->sleeping = 0;
hpts->p_hpts_active = 1;
slots_ran = tcp_hptsi(hpts, true);
tv.tv_sec = 0;
tv.tv_usec = hpts->p_hpts_sleep_time * HPTS_USECS_PER_SLOT;
if ((hpts->p_on_queue_cnt > conn_cnt_thresh) && (hpts->hit_callout_thresh == 0)) {
hpts->hit_callout_thresh = 1;
atomic_add_int(&hpts_that_need_softclock, 1);
} else if ((hpts->p_on_queue_cnt <= conn_cnt_thresh) && (hpts->hit_callout_thresh == 1)) {
hpts->hit_callout_thresh = 0;
atomic_subtract_int(&hpts_that_need_softclock, 1);
}
if (hpts->p_on_queue_cnt >= conn_cnt_thresh) {
if(hpts->p_direct_wake == 0) {
/*
* Only adjust sleep time if we were
* called from the callout i.e. direct_wake == 0.
*/
if (slots_ran < slots_indicate_more_sleep) {
hpts->p_mysleep.tv_usec *= 2;
if (hpts->p_mysleep.tv_usec > dynamic_max_sleep)
hpts->p_mysleep.tv_usec = dynamic_max_sleep;
} else if (slots_ran > slots_indicate_less_sleep) {
hpts->p_mysleep.tv_usec /= 2;
if (hpts->p_mysleep.tv_usec < dynamic_min_sleep)
hpts->p_mysleep.tv_usec = dynamic_min_sleep;
}
}
if (tv.tv_usec < hpts->p_mysleep.tv_usec) {
hpts->overidden_sleep = tv.tv_usec;
tv.tv_usec = hpts->p_mysleep.tv_usec;
} else if (tv.tv_usec > dynamic_max_sleep) {
/* Lets not let sleep get above this value */
hpts->overidden_sleep = tv.tv_usec;
tv.tv_usec = dynamic_max_sleep;
}
/*
* In this mode the timer is a backstop to
* all the lro_flushes so we use
* the dynamic value and set the on_min_sleep
* flag so we will not be awoken.
*/
hpts->p_on_min_sleep = 1;
} else if (hpts->p_on_queue_cnt == 0) {
/*
* No one on the wheel, please wake us up
* if you insert on the wheel.
*/
hpts->p_on_min_sleep = 0;
hpts->overidden_sleep = 0;
} else {
/*
* We hit here when we have a low number of
* clients on the wheel (our else clause).
* We may need to go on min sleep, if we set
* the flag we will not be awoken if someone
* is inserted ahead of us. Clearing the flag
* means we can be awoken. This is "old mode"
* where the timer is what runs hpts mainly.
*/
if (tv.tv_usec < tcp_min_hptsi_time) {
/*
* Yes on min sleep, which means
* we cannot be awoken.
*/
hpts->overidden_sleep = tv.tv_usec;
tv.tv_usec = tcp_min_hptsi_time;
hpts->p_on_min_sleep = 1;
} else {
/* Clear the min sleep flag */
hpts->overidden_sleep = 0;
hpts->p_on_min_sleep = 0;
}
}
HPTS_MTX_ASSERT(hpts);
hpts->p_hpts_active = 0;
back_to_sleep:
hpts->p_direct_wake = 0;
(void)tcp_hpts_sleep(hpts, &tv);
NET_EPOCH_EXIT(et);
HPTS_UNLOCK(hpts);
}
static int32_t
hpts_count_level(struct cpu_group *cg)
{
int32_t count_l3, i;
count_l3 = 0;
if (cg->cg_level == CG_SHARE_L3)
count_l3++;
/* Walk all the children looking for L3 */
for (i = 0; i < cg->cg_children; i++) {
count_l3 += hpts_count_level(&cg->cg_child[i]);
}
return (count_l3);
}
static void
hpts_gather_grps(struct cpu_group **grps, int32_t *at, int32_t max, struct cpu_group *cg)
{
int32_t idx, i;
idx = *at;
if (cg->cg_level == CG_SHARE_L3) {
grps[idx] = cg;
idx++;
if (idx == max) {
*at = idx;
return;
}
}
*at = idx;
/* Walk all the children looking for L3 */
for (i = 0; i < cg->cg_children; i++) {
hpts_gather_grps(grps, at, max, &cg->cg_child[i]);
}
}
/*
* Initialize a tcp_hptsi structure. This performs the core initialization
* without starting threads.
*/
struct tcp_hptsi*
tcp_hptsi_create(const struct tcp_hptsi_funcs *funcs, bool enable_sysctl)
{
struct tcp_hptsi *pace;
struct cpu_group *cpu_top;
uint32_t i, j, cts;
int32_t count;
size_t sz, asz;
struct timeval tv;
struct tcp_hpts_entry *hpts;
char unit[16];
uint32_t ncpus = mp_ncpus ? mp_ncpus : MAXCPU;
KASSERT(funcs != NULL, ("funcs is NULL"));
/* Allocate the main structure */
pace = malloc(sizeof(struct tcp_hptsi), M_TCPHPTS, M_WAITOK | M_ZERO);
if (pace == NULL)
return (NULL);
memset(pace, 0, sizeof(*pace));
pace->funcs = funcs;
/* Setup CPU topology information */
#ifdef SMP
cpu_top = smp_topo();
#else
cpu_top = NULL;
#endif
pace->rp_num_hptss = ncpus;
/* Allocate hpts entry array */
sz = (pace->rp_num_hptss * sizeof(struct tcp_hpts_entry *));
pace->rp_ent = malloc(sz, M_TCPHPTS, M_WAITOK | M_ZERO);
/* Allocate timestamp tracking array */
sz = (sizeof(uint32_t) * pace->rp_num_hptss);
pace->cts_last_ran = malloc(sz, M_TCPHPTS, M_WAITOK);
/* Setup CPU groups */
if (cpu_top == NULL) {
pace->grp_cnt = 1;
} else {
/* Find out how many cache level 3 domains we have */
count = 0;
pace->grp_cnt = hpts_count_level(cpu_top);
if (pace->grp_cnt == 0) {
pace->grp_cnt = 1;
}
sz = (pace->grp_cnt * sizeof(struct cpu_group *));
pace->grps = malloc(sz, M_TCPHPTS, M_WAITOK);
/* Now populate the groups */
if (pace->grp_cnt == 1) {
/*
* All we need is the top level all cpu's are in
* the same cache so when we use grp[0]->cg_mask
* with the cg_first <-> cg_last it will include
* all cpu's in it. The level here is probably
* zero which is ok.
*/
pace->grps[0] = cpu_top;
} else {
/*
* Here we must find all the level three cache domains
* and setup our pointers to them.
*/
count = 0;
hpts_gather_grps(pace->grps, &count, pace->grp_cnt, cpu_top);
}
}
/* Cache the current time for initializing the hpts entries */
microuptime(&tv);
cts = tcp_tv_to_usec(&tv);
/* Initialize each hpts entry */
asz = sizeof(struct hptsh) * NUM_OF_HPTSI_SLOTS;
for (i = 0; i < pace->rp_num_hptss; i++) {
pace->rp_ent[i] = malloc(sizeof(struct tcp_hpts_entry),
M_TCPHPTS, M_WAITOK | M_ZERO);
pace->rp_ent[i]->p_hptss = malloc(asz, M_TCPHPTS,
M_WAITOK | M_ZERO);
hpts = pace->rp_ent[i];
/* Basic initialization */
hpts->p_hpts_sleep_time = hpts_sleep_max;
hpts->p_cpu = i;
pace->cts_last_ran[i] = cts;
hpts->p_cur_slot = cts_to_wheel(cts);
hpts->p_prev_slot = hpts->p_cur_slot;
hpts->p_nxt_slot = hpts_slot(hpts->p_cur_slot, 1);
callout_init(&hpts->co, 1);
hpts->p_hptsi = pace;
mtx_init(&hpts->p_mtx, "tcp_hpts_lck", "hpts",
MTX_DEF | MTX_DUPOK);
for (j = 0; j < NUM_OF_HPTSI_SLOTS; j++) {
TAILQ_INIT(&hpts->p_hptss[j].head);
}
/* Setup SYSCTL if requested */
if (enable_sysctl) {
sysctl_ctx_init(&hpts->hpts_ctx);
sprintf(unit, "%d", i);
hpts->hpts_root = SYSCTL_ADD_NODE(&hpts->hpts_ctx,
SYSCTL_STATIC_CHILDREN(_net_inet_tcp_hpts),
OID_AUTO,
unit,
CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"");
SYSCTL_ADD_INT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "out_qcnt", CTLFLAG_RD,
&hpts->p_on_queue_cnt, 0,
"Count TCB's awaiting output processing");
SYSCTL_ADD_U16(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "active", CTLFLAG_RD,
&hpts->p_hpts_active, 0,
"Is the hpts active");
SYSCTL_ADD_UINT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "curslot", CTLFLAG_RD,
&hpts->p_cur_slot, 0,
"What the current running pacers goal");
SYSCTL_ADD_UINT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "runslot", CTLFLAG_RD,
&hpts->p_runningslot, 0,
"What the running pacers current slot is");
SYSCTL_ADD_UINT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "lastran", CTLFLAG_RD,
&pace->cts_last_ran[i], 0,
"The last usec timestamp that this hpts ran");
SYSCTL_ADD_LONG(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "cur_min_sleep", CTLFLAG_RD,
&hpts->p_mysleep.tv_usec,
"What the running pacers is using for p_mysleep.tv_usec");
SYSCTL_ADD_U64(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "now_sleeping", CTLFLAG_RD,
&hpts->sleeping, 0,
"What the running pacers is actually sleeping for");
SYSCTL_ADD_U64(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "syscall_cnt", CTLFLAG_RD,
&hpts->syscall_cnt, 0,
"How many times we had syscalls on this hpts");
}
}
return (pace);
}
/*
* Create threads for a tcp_hptsi structure and starts timers for the current
* (minimum) sleep interval.
*/
void
tcp_hptsi_start(struct tcp_hptsi *pace)
{
struct tcp_hpts_entry *hpts;
struct pcpu *pc;
struct timeval tv;
uint32_t i, j;
int count, domain;
int error __diagused;
KASSERT(pace != NULL, ("tcp_hptsi_start: pace is NULL"));
/* Start threads for each hpts entry */
for (i = 0; i < pace->rp_num_hptss; i++) {
hpts = pace->rp_ent[i];
KASSERT(hpts->ie_cookie == NULL,
("tcp_hptsi_start: hpts[%d]->ie_cookie is not NULL", i));
error = swi_add(&hpts->ie, "hpts",
tcp_hpts_thread, (void *)hpts,
SWI_NET, INTR_MPSAFE, &hpts->ie_cookie);
KASSERT(error == 0,
("Can't add hpts:%p i:%d err:%d", hpts, i, error));
if (tcp_bind_threads == 1) {
(void)intr_event_bind(hpts->ie, i);
} else if (tcp_bind_threads == 2) {
/* Find the group for this CPU (i) and bind into it */
for (j = 0; j < pace->grp_cnt; j++) {
if (CPU_ISSET(i, &pace->grps[j]->cg_mask)) {
if (intr_event_bind_ithread_cpuset(hpts->ie,
&pace->grps[j]->cg_mask) == 0) {
pc = pcpu_find(i);
domain = pc->pc_domain;
count = pace->domains[domain].count;
pace->domains[domain].cpu[count] = i;
pace->domains[domain].count++;
break;
}
}
}
}
hpts->p_mysleep.tv_sec = 0;
hpts->p_mysleep.tv_usec = tcp_min_hptsi_time;
tv.tv_sec = 0;
tv.tv_usec = hpts->p_hpts_sleep_time * HPTS_USECS_PER_SLOT;
(void)tcp_hpts_sleep(hpts, &tv);
}
}
/*
* Stop all callouts/threads for a tcp_hptsi structure.
*/
void
tcp_hptsi_stop(struct tcp_hptsi *pace)
{
struct tcp_hpts_entry *hpts;
int rv __diagused;
uint32_t i;
KASSERT(pace != NULL, ("tcp_hptsi_stop: pace is NULL"));
for (i = 0; i < pace->rp_num_hptss; i++) {
hpts = pace->rp_ent[i];
KASSERT(hpts != NULL, ("tcp_hptsi_stop: hpts[%d] is NULL", i));
KASSERT(hpts->ie_cookie != NULL,
("tcp_hptsi_stop: hpts[%d]->ie_cookie is NULL", i));
rv = _callout_stop_safe(&hpts->co, CS_DRAIN);
MPASS(rv != 0);
rv = swi_remove(hpts->ie_cookie);
MPASS(rv == 0);
hpts->ie_cookie = NULL;
}
}
/*
* Destroy a tcp_hptsi structure initialized by tcp_hptsi_create.
*/
void
tcp_hptsi_destroy(struct tcp_hptsi *pace)
{
struct tcp_hpts_entry *hpts;
uint32_t i;
KASSERT(pace != NULL, ("tcp_hptsi_destroy: pace is NULL"));
KASSERT(pace->rp_ent != NULL, ("tcp_hptsi_destroy: pace->rp_ent is NULL"));
/* Cleanup each hpts entry */
for (i = 0; i < pace->rp_num_hptss; i++) {
hpts = pace->rp_ent[i];
if (hpts != NULL) {
/* Cleanup SYSCTL if it was initialized */
if (hpts->hpts_root != NULL) {
sysctl_ctx_free(&hpts->hpts_ctx);
}
mtx_destroy(&hpts->p_mtx);
free(hpts->p_hptss, M_TCPHPTS);
free(hpts, M_TCPHPTS);
}
}
/* Cleanup main arrays */
free(pace->rp_ent, M_TCPHPTS);
free(pace->cts_last_ran, M_TCPHPTS);
#ifdef SMP
free(pace->grps, M_TCPHPTS);
#endif
/* Free the main structure */
free(pace, M_TCPHPTS);
}
static int
tcp_hpts_mod_load(void)
{
int i;
/* Don't try to bind to NUMA domains if we don't have any */
if (vm_ndomains == 1 && tcp_bind_threads == 2)
tcp_bind_threads = 0;
/* Create the tcp_hptsi structure */
tcp_hptsi_pace = tcp_hptsi_create(&tcp_hptsi_default_funcs, true);
if (tcp_hptsi_pace == NULL)
return (ENOMEM);
/* Initialize global counters */
hpts_hopelessly_behind = counter_u64_alloc(M_WAITOK);
hpts_loops = counter_u64_alloc(M_WAITOK);
back_tosleep = counter_u64_alloc(M_WAITOK);
combined_wheel_wrap = counter_u64_alloc(M_WAITOK);
wheel_wrap = counter_u64_alloc(M_WAITOK);
hpts_wake_timeout = counter_u64_alloc(M_WAITOK);
hpts_direct_awakening = counter_u64_alloc(M_WAITOK);
hpts_back_tosleep = counter_u64_alloc(M_WAITOK);
hpts_direct_call = counter_u64_alloc(M_WAITOK);
cpu_uses_flowid = counter_u64_alloc(M_WAITOK);
cpu_uses_random = counter_u64_alloc(M_WAITOK);
/* Start the threads */
tcp_hptsi_start(tcp_hptsi_pace);
/* Initialize LRO HPTS */
tcp_lro_hpts_init();
/*
* If we somehow have an empty domain, fall back to choosing among all
* HPTS threads.
*/
for (i = 0; i < vm_ndomains; i++) {
if (tcp_hptsi_pace->domains[i].count == 0) {
tcp_bind_threads = 0;
break;
}
}
printf("TCP HPTS started %u (%s) swi interrupt threads\n",
tcp_hptsi_pace->rp_num_hptss, (tcp_bind_threads == 0) ?
"(unbounded)" :
(tcp_bind_threads == 1 ? "per-cpu" : "per-NUMA-domain"));
return (0);
}
static void
tcp_hpts_mod_unload(void)
{
tcp_lro_hpts_uninit();
tcp_hptsi_stop(tcp_hptsi_pace);
tcp_hptsi_destroy(tcp_hptsi_pace);
tcp_hptsi_pace = NULL;
/* Cleanup global counters */
counter_u64_free(hpts_hopelessly_behind);
counter_u64_free(hpts_loops);
counter_u64_free(back_tosleep);
counter_u64_free(combined_wheel_wrap);
counter_u64_free(wheel_wrap);
counter_u64_free(hpts_wake_timeout);
counter_u64_free(hpts_direct_awakening);
counter_u64_free(hpts_back_tosleep);
counter_u64_free(hpts_direct_call);
counter_u64_free(cpu_uses_flowid);
counter_u64_free(cpu_uses_random);
}
static int
tcp_hpts_mod_event(module_t mod, int what, void *arg)
{
switch (what) {
case MOD_LOAD:
return (tcp_hpts_mod_load());
case MOD_QUIESCE:
/*
* Since we are a dependency of TCP stack modules, they should
* already be unloaded, and the HPTS ring is empty. However,
* function pointer manipulations aren't 100% safe.
* Thus, allow only forced unload of HPTS.
*/
return (EBUSY);
case MOD_UNLOAD:
tcp_hpts_mod_unload();
return (0);
default:
return (EINVAL);
};
}
static moduledata_t tcp_hpts_module = {
.name = "tcphpts",
.evhand = tcp_hpts_mod_event,
};
DECLARE_MODULE(tcphpts, tcp_hpts_module, SI_SUB_SOFTINTR, SI_ORDER_ANY);
MODULE_VERSION(tcphpts, 1);
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