5.4-stable review patch. If anyone has any objections, please let me know.
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From: He Rongguang herongguang@linux.alibaba.com
[ 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 --- .../cpupower/utils/idle_monitor/mperf_monitor.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c b/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c index 7a76d63003748..0e8c0b879d4b2 100644 --- a/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c +++ b/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c @@ -29,7 +29,7 @@ static int mperf_get_count_percent(unsigned int self_id, double *percent, unsigned int cpu); static int mperf_get_count_freq(unsigned int id, unsigned long long *count, unsigned int cpu); -static struct timespec time_start, time_end; +static struct timespec *time_start, *time_end;
static cstate_t mperf_cstates[MPERF_CSTATE_COUNT] = { { @@ -135,7 +135,7 @@ static int mperf_get_count_percent(unsigned int id, double *percent, dprint("%s: TSC Ref - mperf_diff: %llu, tsc_diff: %llu\n", mperf_cstates[id].name, mperf_diff, tsc_diff); } else if (max_freq_mode == MAX_FREQ_SYSFS) { - timediff = max_frequency * timespec_diff_us(time_start, time_end); + timediff = max_frequency * timespec_diff_us(time_start[cpu], time_end[cpu]); *percent = 100.0 * mperf_diff / timediff; dprint("%s: MAXFREQ - mperf_diff: %llu, time_diff: %llu\n", mperf_cstates[id].name, mperf_diff, timediff); @@ -168,7 +168,7 @@ static int mperf_get_count_freq(unsigned int id, unsigned long long *count, if (max_freq_mode == MAX_FREQ_TSC_REF) { /* Calculate max_freq from TSC count */ tsc_diff = tsc_at_measure_end[cpu] - tsc_at_measure_start[cpu]; - time_diff = timespec_diff_us(time_start, time_end); + time_diff = timespec_diff_us(time_start[cpu], time_end[cpu]); max_frequency = tsc_diff / time_diff; }
@@ -187,9 +187,8 @@ static int mperf_start(void) { int cpu;
- clock_gettime(CLOCK_REALTIME, &time_start); - for (cpu = 0; cpu < cpu_count; cpu++) { + clock_gettime(CLOCK_REALTIME, &time_start[cpu]); mperf_get_tsc(&tsc_at_measure_start[cpu]); mperf_init_stats(cpu); } @@ -204,9 +203,9 @@ static int mperf_stop(void) for (cpu = 0; cpu < cpu_count; cpu++) { mperf_measure_stats(cpu); mperf_get_tsc(&tsc_at_measure_end[cpu]); + clock_gettime(CLOCK_REALTIME, &time_end[cpu]); }
- clock_gettime(CLOCK_REALTIME, &time_end); return 0; }
@@ -307,6 +306,8 @@ struct cpuidle_monitor *mperf_register(void) aperf_current_count = calloc(cpu_count, sizeof(unsigned long long)); tsc_at_measure_start = calloc(cpu_count, sizeof(unsigned long long)); tsc_at_measure_end = calloc(cpu_count, sizeof(unsigned long long)); + time_start = calloc(cpu_count, sizeof(struct timespec)); + time_end = calloc(cpu_count, sizeof(struct timespec)); mperf_monitor.name_len = strlen(mperf_monitor.name); return &mperf_monitor; } @@ -319,6 +320,8 @@ void mperf_unregister(void) free(aperf_current_count); free(tsc_at_measure_start); free(tsc_at_measure_end); + free(time_start); + free(time_end); free(is_valid); }