This is a note to let you know that I've just added the patch titled
cpupower: fix TSC MHz calculation
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cpupower-fix-tsc-mhz-calculation.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e981dff073836ce823ec367a437107986b8b20cc
Author: He Rongguang <herongguang@xxxxxxxxxxxxxxxxx>
Date: Thu Dec 12 10:14:59 2024 +0800
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@xxxxxxxxxxxxxxxxx>
Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c b/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c
index ae6af354a81db..08a399b0be286 100644
--- a/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c
+++ b/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c
@@ -33,7 +33,7 @@ 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] = {
{
@@ -174,7 +174,7 @@ 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);
@@ -207,7 +207,7 @@ 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;
}
@@ -226,9 +226,8 @@ 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);
}
@@ -243,9 +242,9 @@ 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;
}
@@ -349,6 +348,8 @@ 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;
}
@@ -361,6 +362,8 @@ 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);
}
