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Yang Yang
662ce1dc9c
Delay accounting does not track the delay of write-protect copy. When
tasks trigger many write-protect copys(include COW and unsharing of
anonymous pages[1]), it may spend a amount of time waiting for them. To
get the delay of tasks in write-protect copy, could help users to evaluate
the impact of using KSM or fork() or GUP.
Also update tools/accounting/getdelays.c:
/ # ./getdelays -dl -p 231
print delayacct stats ON
listen forever
PID 231
CPU count real total virtual total delay total delay average
6247 1859000000 2154070021 1674255063 0.268ms
IO count delay total delay average
0 0 0ms
SWAP count delay total delay average
0 0 0ms
RECLAIM count delay total delay average
0 0 0ms
THRASHING count delay total delay average
0 0 0ms
COMPACT count delay total delay average
3 72758 0ms
WPCOPY count delay total delay average
3635 271567604 0ms
[1] commit 31cc5bc4af70("mm: support GUP-triggered unsharing of anonymous pages")
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Yang Yang <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Reviewed-by: Jiang Xuexin <[email protected]>
Reviewed-by: Ran Xiaokai <[email protected]>
Reviewed-by: wangyong <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>