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authorHe Rongguang <herongguang@linux.alibaba.com>2024-12-12 10:14:59 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-02-08 09:57:05 +0100
commit4a3b902a4aa3e2cfc433c677d5e2b35ca97b052f (patch)
tree3e292cf46faa6aa3f2825af4168dd1b13d5d8304 /Documentation
parent285412c1f0e3d329185ce8c3d1976dfb2c41c608 (diff)
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cpupower: fix TSC MHz calculation
[ Upstream commit 9d6c0e58514f8b57cd9c2c755e41623d6a966025 ] Commit 'cpupower: Make TSC read per CPU for Mperf monitor' (c2adb1877b7) changes TSC counter reads per cpu, but left time diff global (from start of all cpus to end of all cpus), thus diff(time) is too large for a cpu's tsc counting, resulting in far less than acutal TSC_Mhz and thus `cpupower monitor` showing far less than actual cpu realtime frequency. /proc/cpuinfo shows frequency: cat /proc/cpuinfo | egrep -e 'processor' -e 'MHz' ... processor : 171 cpu MHz : 4108.498 ... before fix (System 100% busy): | Mperf || Idle_Stats CPU| C0 | Cx | Freq || POLL | C1 | C2 171| 0.77| 99.23| 2279|| 0.00| 0.00| 0.00 after fix (System 100% busy): | Mperf || Idle_Stats CPU| C0 | Cx | Freq || POLL | C1 | C2 171| 0.46| 99.54| 4095|| 0.00| 0.00| 0.00 Fixes: c2adb1877b76 ("cpupower: Make TSC read per CPU for Mperf monitor") Signed-off-by: He Rongguang <herongguang@linux.alibaba.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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