[linux-nvidia-6.17] Backport perf: Fix 0 count issue of cpu-clock#309
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nvmochs wants to merge 1 commit intoNVIDIA:24.04_linux-nvidia-6.17-nextfrom
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[linux-nvidia-6.17] Backport perf: Fix 0 count issue of cpu-clock#309nvmochs wants to merge 1 commit intoNVIDIA:24.04_linux-nvidia-6.17-nextfrom
nvmochs wants to merge 1 commit intoNVIDIA:24.04_linux-nvidia-6.17-nextfrom
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Currently cpu-clock event always returns 0 count, e.g.,
perf stat -e cpu-clock -- sleep 1
Performance counter stats for 'sleep 1':
0 cpu-clock # 0.000 CPUs utilized
1.002308394 seconds time elapsed
The root cause is the commit 'bc4394e5e79c ("perf: Fix the throttle
error of some clock events")' adds PERF_EF_UPDATE flag check before
calling cpu_clock_event_update() to update the count, however the
PERF_EF_UPDATE flag is never set when the cpu-clock event is stopped in
counting mode (pmu->dev() -> cpu_clock_event_del() ->
cpu_clock_event_stop()). This leads to the cpu-clock event count is
never updated.
To fix this issue, force to set PERF_EF_UPDATE flag for cpu-clock event
just like what task-clock does.
Fixes: bc4394e ("perf: Fix the throttle error of some clock events")
Signed-off-by: Dapeng Mi <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Link: https://patch.msgid.link/[email protected]
(cherry picked from commit f1f9651)
Signed-off-by: Matthew R. Ochs <[email protected]>
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Feb 3, 2026
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Acked-by: Carol L Soto <[email protected]>
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jamieNguyenNVIDIA
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Feb 4, 2026
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Currently cpu-clock event always returns 0 count, e.g.,
perf stat -e cpu-clock -- sleep 1
Performance counter stats for 'sleep 1':
0 cpu-clock # 0.000 CPUs utilized
1.002308394 seconds time elapsed
The root cause is the commit 'bc4394e5e79c ("perf: Fix the throttle
error of some clock events")' adds PERF_EF_UPDATE flag check before
calling cpu_clock_event_update() to update the count, however the PERF_EF_UPDATE flag is never set when the cpu-clock event is stopped in counting mode (pmu->dev() -> cpu_clock_event_del() -> cpu_clock_event_stop()). This leads to the cpu-clock event count is never updated.
To fix this issue, force to set PERF_EF_UPDATE flag for cpu-clock event just like what task-clock does.
Fixes: bc4394e ("perf: Fix the throttle error of some clock events")
Reviewed-by: Ian Rogers [email protected]
Acked-by: Namhyung Kim [email protected]
Link: https://patch.msgid.link/[email protected] (cherry picked from commit f1f9651)
LP: https://bugs.launchpad.net/ubuntu/+source/linux-nvidia/+bug/2139648