forked from luck/tmp_suning_uos_patched
cpupower: mperf monitor - Use TSC to calculate max frequency if possible
Which makes the implementation independent from cpufreq drivers. Therefore this would also work on a Xen kernel where the hypervisor is doing frequency switching and idle entering. Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Thomas Renninger
Dominik Brodowski
parent
75f25bd31d
commit
2dfc818b35
|
|
@ -24,7 +24,7 @@
|
|||
|
||||
# Set the following to `true' to make a unstripped, unoptimized
|
||||
# binary. Leave this set to `false' for production use.
|
||||
DEBUG ?= false
|
||||
DEBUG ?= true
|
||||
|
||||
# make the build silent. Set this to something else to make it noisy again.
|
||||
V ?= false
|
||||
|
|
|
|||
|
|
@ -22,12 +22,15 @@
|
|||
|
||||
#define MSR_TSC 0x10
|
||||
|
||||
#define MSR_AMD_HWCR 0xc0010015
|
||||
|
||||
enum mperf_id { C0 = 0, Cx, AVG_FREQ, MPERF_CSTATE_COUNT };
|
||||
|
||||
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 cstate_t mperf_cstates[MPERF_CSTATE_COUNT] = {
|
||||
{
|
||||
|
|
@ -54,19 +57,33 @@ static cstate_t mperf_cstates[MPERF_CSTATE_COUNT] = {
|
|||
},
|
||||
};
|
||||
|
||||
enum MAX_FREQ_MODE { MAX_FREQ_SYSFS, MAX_FREQ_TSC_REF };
|
||||
static int max_freq_mode;
|
||||
/*
|
||||
* The max frequency mperf is ticking at (in C0), either retrieved via:
|
||||
* 1) calculated after measurements if we know TSC ticks at mperf/P0 frequency
|
||||
* 2) cpufreq /sys/devices/.../cpu0/cpufreq/cpuinfo_max_freq at init time
|
||||
* 1. Is preferred as it also works without cpufreq subsystem (e.g. on Xen)
|
||||
*/
|
||||
static unsigned long max_frequency;
|
||||
|
||||
static unsigned long long tsc_at_measure_start;
|
||||
static unsigned long long tsc_at_measure_end;
|
||||
static unsigned long max_frequency;
|
||||
static unsigned long long *mperf_previous_count;
|
||||
static unsigned long long *aperf_previous_count;
|
||||
static unsigned long long *mperf_current_count;
|
||||
static unsigned long long *aperf_current_count;
|
||||
|
||||
/* valid flag for all CPUs. If a MSR read failed it will be zero */
|
||||
static int *is_valid;
|
||||
|
||||
static int mperf_get_tsc(unsigned long long *tsc)
|
||||
{
|
||||
return read_msr(0, MSR_TSC, tsc);
|
||||
int ret;
|
||||
ret = read_msr(0, MSR_TSC, tsc);
|
||||
if (ret)
|
||||
dprint("Reading TSC MSR failed, returning %llu\n", *tsc);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int mperf_init_stats(unsigned int cpu)
|
||||
|
|
@ -97,36 +114,11 @@ static int mperf_measure_stats(unsigned int cpu)
|
|||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* get_average_perf()
|
||||
*
|
||||
* Returns the average performance (also considers boosted frequencies)
|
||||
*
|
||||
* Input:
|
||||
* aperf_diff: Difference of the aperf register over a time period
|
||||
* mperf_diff: Difference of the mperf register over the same time period
|
||||
* max_freq: Maximum frequency (P0)
|
||||
*
|
||||
* Returns:
|
||||
* Average performance over the time period
|
||||
*/
|
||||
static unsigned long get_average_perf(unsigned long long aperf_diff,
|
||||
unsigned long long mperf_diff)
|
||||
{
|
||||
unsigned int perf_percent = 0;
|
||||
if (((unsigned long)(-1) / 100) < aperf_diff) {
|
||||
int shift_count = 7;
|
||||
aperf_diff >>= shift_count;
|
||||
mperf_diff >>= shift_count;
|
||||
}
|
||||
perf_percent = (aperf_diff * 100) / mperf_diff;
|
||||
return (max_frequency * perf_percent) / 100;
|
||||
}
|
||||
|
||||
static int mperf_get_count_percent(unsigned int id, double *percent,
|
||||
unsigned int cpu)
|
||||
{
|
||||
unsigned long long aperf_diff, mperf_diff, tsc_diff;
|
||||
unsigned long long timediff;
|
||||
|
||||
if (!is_valid[cpu])
|
||||
return -1;
|
||||
|
|
@ -136,11 +128,19 @@ static int mperf_get_count_percent(unsigned int id, double *percent,
|
|||
|
||||
mperf_diff = mperf_current_count[cpu] - mperf_previous_count[cpu];
|
||||
aperf_diff = aperf_current_count[cpu] - aperf_previous_count[cpu];
|
||||
tsc_diff = tsc_at_measure_end - tsc_at_measure_start;
|
||||
|
||||
*percent = 100.0 * mperf_diff / tsc_diff;
|
||||
dprint("%s: mperf_diff: %llu, tsc_diff: %llu\n",
|
||||
mperf_cstates[id].name, mperf_diff, tsc_diff);
|
||||
if (max_freq_mode == MAX_FREQ_TSC_REF) {
|
||||
tsc_diff = tsc_at_measure_end - tsc_at_measure_start;
|
||||
*percent = 100.0 * mperf_diff / tsc_diff;
|
||||
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 = timespec_diff_us(time_start, time_end);
|
||||
*percent = 100.0 * mperf_diff / timediff;
|
||||
dprint("%s: MAXFREQ - mperf_diff: %llu, time_diff: %llu\n",
|
||||
mperf_cstates[id].name, mperf_diff, timediff);
|
||||
} else
|
||||
return -1;
|
||||
|
||||
if (id == Cx)
|
||||
*percent = 100.0 - *percent;
|
||||
|
|
@ -154,7 +154,7 @@ static int mperf_get_count_percent(unsigned int id, double *percent,
|
|||
static int mperf_get_count_freq(unsigned int id, unsigned long long *count,
|
||||
unsigned int cpu)
|
||||
{
|
||||
unsigned long long aperf_diff, mperf_diff;
|
||||
unsigned long long aperf_diff, mperf_diff, time_diff, tsc_diff;
|
||||
|
||||
if (id != AVG_FREQ)
|
||||
return 1;
|
||||
|
|
@ -165,11 +165,21 @@ static int mperf_get_count_freq(unsigned int id, unsigned long long *count,
|
|||
mperf_diff = mperf_current_count[cpu] - mperf_previous_count[cpu];
|
||||
aperf_diff = aperf_current_count[cpu] - aperf_previous_count[cpu];
|
||||
|
||||
/* Return MHz for now, might want to return KHz if column width is more
|
||||
generic */
|
||||
*count = get_average_perf(aperf_diff, mperf_diff) / 1000;
|
||||
dprint("%s: %llu\n", mperf_cstates[id].name, *count);
|
||||
if (max_freq_mode == MAX_FREQ_TSC_REF) {
|
||||
/* Calculate max_freq from TSC count */
|
||||
tsc_diff = tsc_at_measure_end - tsc_at_measure_start;
|
||||
time_diff = timespec_diff_us(time_start, time_end);
|
||||
max_frequency = tsc_diff / time_diff;
|
||||
}
|
||||
|
||||
*count = max_frequency * ((double)aperf_diff / mperf_diff);
|
||||
dprint("%s: Average freq based on %s maximum frequency:\n",
|
||||
mperf_cstates[id].name,
|
||||
(max_freq_mode == MAX_FREQ_TSC_REF) ? "TSC calculated" : "sysfs read");
|
||||
dprint("%max_frequency: %lu", max_frequency);
|
||||
dprint("aperf_diff: %llu\n", aperf_diff);
|
||||
dprint("mperf_diff: %llu\n", mperf_diff);
|
||||
dprint("avg freq: %llu\n", *count);
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
@ -178,6 +188,7 @@ static int mperf_start(void)
|
|||
int cpu;
|
||||
unsigned long long dbg;
|
||||
|
||||
clock_gettime(CLOCK_REALTIME, &time_start);
|
||||
mperf_get_tsc(&tsc_at_measure_start);
|
||||
|
||||
for (cpu = 0; cpu < cpu_count; cpu++)
|
||||
|
|
@ -193,32 +204,104 @@ static int mperf_stop(void)
|
|||
unsigned long long dbg;
|
||||
int cpu;
|
||||
|
||||
mperf_get_tsc(&tsc_at_measure_end);
|
||||
|
||||
for (cpu = 0; cpu < cpu_count; cpu++)
|
||||
mperf_measure_stats(cpu);
|
||||
|
||||
mperf_get_tsc(&tsc_at_measure_end);
|
||||
clock_gettime(CLOCK_REALTIME, &time_end);
|
||||
|
||||
mperf_get_tsc(&dbg);
|
||||
dprint("TSC diff: %llu\n", dbg - tsc_at_measure_end);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
struct cpuidle_monitor mperf_monitor;
|
||||
|
||||
struct cpuidle_monitor *mperf_register(void)
|
||||
/*
|
||||
* Mperf register is defined to tick at P0 (maximum) frequency
|
||||
*
|
||||
* Instead of reading out P0 which can be tricky to read out from HW,
|
||||
* we use TSC counter if it reliably ticks at P0/mperf frequency.
|
||||
*
|
||||
* Still try to fall back to:
|
||||
* /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq
|
||||
* on older Intel HW without invariant TSC feature.
|
||||
* Or on AMD machines where TSC does not tick at P0 (do not exist yet, but
|
||||
* it's still double checked (MSR_AMD_HWCR)).
|
||||
*
|
||||
* On these machines the user would still get useful mperf
|
||||
* stats when acpi-cpufreq driver is loaded.
|
||||
*/
|
||||
static int init_maxfreq_mode(void)
|
||||
{
|
||||
int ret;
|
||||
unsigned long long hwcr;
|
||||
unsigned long min;
|
||||
|
||||
if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_APERF))
|
||||
return NULL;
|
||||
if (!cpupower_cpu_info.caps & CPUPOWER_CAP_INV_TSC)
|
||||
goto use_sysfs;
|
||||
|
||||
/* Assume min/max all the same on all cores */
|
||||
if (cpupower_cpu_info.vendor == X86_VENDOR_AMD) {
|
||||
/* MSR_AMD_HWCR tells us whether TSC runs at P0/mperf
|
||||
* freq.
|
||||
* A test whether hwcr is accessable/available would be:
|
||||
* (cpupower_cpu_info.family > 0x10 ||
|
||||
* cpupower_cpu_info.family == 0x10 &&
|
||||
* cpupower_cpu_info.model >= 0x2))
|
||||
* This should be the case for all aperf/mperf
|
||||
* capable AMD machines and is therefore safe to test here.
|
||||
* Compare with Linus kernel git commit: acf01734b1747b1ec4
|
||||
*/
|
||||
ret = read_msr(0, MSR_AMD_HWCR, &hwcr);
|
||||
/*
|
||||
* If the MSR read failed, assume a Xen system that did
|
||||
* not explicitly provide access to it and assume TSC works
|
||||
*/
|
||||
if (ret != 0) {
|
||||
dprint("TSC read 0x%x failed - assume TSC working\n",
|
||||
MSR_AMD_HWCR);
|
||||
return 0;
|
||||
} else if (1 & (hwcr >> 24)) {
|
||||
max_freq_mode = MAX_FREQ_TSC_REF;
|
||||
return 0;
|
||||
} else { /* Use sysfs max frequency if available */ }
|
||||
} else if (cpupower_cpu_info.vendor == X86_VENDOR_INTEL) {
|
||||
/*
|
||||
* On Intel we assume mperf (in C0) is ticking at same
|
||||
* rate than TSC
|
||||
*/
|
||||
max_freq_mode = MAX_FREQ_TSC_REF;
|
||||
return 0;
|
||||
}
|
||||
use_sysfs:
|
||||
if (cpufreq_get_hardware_limits(0, &min, &max_frequency)) {
|
||||
dprint("Cannot retrieve max freq from cpufreq kernel "
|
||||
"subsystem\n");
|
||||
return NULL;
|
||||
return -1;
|
||||
}
|
||||
max_freq_mode = MAX_FREQ_SYSFS;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* This monitor provides:
|
||||
*
|
||||
* 1) Average frequency a CPU resided in
|
||||
* This always works if the CPU has aperf/mperf capabilities
|
||||
*
|
||||
* 2) C0 and Cx (any sleep state) time a CPU resided in
|
||||
* Works if mperf timer stops ticking in sleep states which
|
||||
* seem to be the case on all current HW.
|
||||
* Both is directly retrieved from HW registers and is independent
|
||||
* from kernel statistics.
|
||||
*/
|
||||
struct cpuidle_monitor mperf_monitor;
|
||||
struct cpuidle_monitor *mperf_register(void)
|
||||
{
|
||||
if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_APERF))
|
||||
return NULL;
|
||||
|
||||
if (init_maxfreq_mode())
|
||||
return NULL;
|
||||
|
||||
/* Free this at program termination */
|
||||
is_valid = calloc(cpu_count, sizeof(int));
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user