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Ian Rogers
207f7df727
Knowing the topology of online CPUs is useful for more than just expr literals. Move to a global function that caches the value. An additional upside is that this may also avoid computing the CPU topology in some situations. Signed-off-by: Ian Rogers <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Alexandre Torgue <[email protected]> Cc: Andrii Nakryiko <[email protected]> Cc: Athira Rajeev <[email protected]> Cc: Caleb Biggers <[email protected]> Cc: Eduard Zingerman <[email protected]> Cc: Florian Fischer <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: James Clark <[email protected]> Cc: Jing Zhang <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: John Garry <[email protected]> Cc: Kajol Jain <[email protected]> Cc: Kan Liang <[email protected]> Cc: Leo Yan <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Maxime Coquelin <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Perry Taylor <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Ravi Bangoria <[email protected]> Cc: Sandipan Das <[email protected]> Cc: Sean Christopherson <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Suzuki Poulouse <[email protected]> Cc: Xing Zhengjun <[email protected]> Cc: [email protected] Cc: [email protected] Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
37 lines
850 B
C
37 lines
850 B
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <string.h>
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#include "api/fs/fs.h"
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#include "cputopo.h"
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#include "smt.h"
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bool smt_on(void)
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{
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static bool cached;
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static bool cached_result;
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int fs_value;
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if (cached)
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return cached_result;
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if (sysfs__read_int("devices/system/cpu/smt/active", &fs_value) >= 0)
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cached_result = (fs_value == 1);
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else
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cached_result = cpu_topology__smt_on(online_topology());
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cached = true;
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return cached_result;
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}
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bool core_wide(bool system_wide, const char *user_requested_cpu_list)
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{
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/* If not everything running on a core is being recorded then we can't use core_wide. */
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if (!system_wide)
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return false;
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/* Cheap case that SMT is disabled and therefore we're inherently core_wide. */
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if (!smt_on())
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return true;
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return cpu_topology__core_wide(online_topology(), user_requested_cpu_list);
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}
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