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cpupower: fix TSC MHz calculation

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[ Upstream commit 9d6c0e5851 ]

Commit 'cpupower: Make TSC read per CPU for Mperf monitor' (c2adb1877b)
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: c2adb1877b ("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>
This commit is contained in:
He Rongguang
2024-12-12 10:14:59 +08:00
committed by Greg Kroah-Hartman
parent 167483d91a
commit 6f4354ca0c
1 changed files with 9 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tools/power/cpupower/utils/idle_monitor/mperf_monitor.c
+9 -6
View File
@@ -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);
}