kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-10-20 19:23:40 +00:00
Code Issues Releases Packages Activity
linux/tools/power
History
Gautham R. Shenoy eb636446e3 pm: cpupower: Fix the snapshot-order of tsc,mperf, clock in mperf_stop() 
[ Upstream commit cda7ac8ce7 ]

In the function mperf_start(), mperf_monitor snapshots the time, tsc
and finally the aperf,mperf MSRs. However, this order of snapshotting
in is reversed in mperf_stop(). As a result, the C0 residency (which
is computed as delta_mperf * 100 / delta_tsc) is under-reported on
CPUs that is 100% busy.

Fix this by snapshotting time, tsc and then aperf,mperf in
mperf_stop() in the same order as in mperf_start().

Link: https://lore.kernel.org/r/20250612122355.19629-2-gautham.shenoy@amd.com
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-08-28 16:25:54 +02:00
..
acpi ACPI: tools: pfrut: Check if the input of level and type is in the right numeric range 2023-04-06 12:10:40 +02:00
cpupower pm: cpupower: Fix the snapshot-order of tsc,mperf, clock in mperf_stop() 2025-08-28 16:25:54 +02:00
pm-graph pm-graph v5.10 2022-10-25 17:46:15 +02:00
x86 tools/power turbostat: Remember global max_die_id 2024-07-11 12:47:10 +02:00