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tools/power turbostat: work around RC6 counter wrap

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Sometimes the rc6 sysfs counter spontaneously resets,
causing turbostat prints a very large number
as it tries to calcuate % = 100 * (old - new) / interval

When we see (old > new), print ***.**% instead
of a bogus huge number.

Note that this detection is not fool-proof, as the counter
could reset several times and still result in new > old.

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Len Brown 2016-04-06 17:16:00 -04:00 committed by Rafael J. Wysocki
parent cdc57272ea
commit 9185e988e9
1 changed files with 15 additions and 4 deletions
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19
tools/power/x86/turbostat/turbostat.c
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@ -189,7 +189,7 @@ struct pkg_data {
unsigned long long pkg_any_core_c0;
unsigned long long pkg_any_gfxe_c0;
unsigned long long pkg_both_core_gfxe_c0;
unsigned long long gfx_rc6_ms;
long long gfx_rc6_ms;
unsigned int gfx_mhz;
unsigned int package_id;
unsigned int energy_pkg; /* MSR_PKG_ENERGY_STATUS */
@ -623,8 +623,14 @@ int format_counters(struct thread_data *t, struct core_data *c,
outp += sprintf(outp, "%8d", p->pkg_temp_c);
/* GFXrc6 */
if (do_gfx_rc6_ms)
outp += sprintf(outp, "%8.2f", 100.0 * p->gfx_rc6_ms / 1000.0 / interval_float);
if (do_gfx_rc6_ms) {
if (p->gfx_rc6_ms == -1) { /* detect counter reset */
outp += sprintf(outp, " ***.**");
} else {
outp += sprintf(outp, "%8.2f",
p->gfx_rc6_ms / 10.0 / interval_float);
}
}
/* GFXMHz */
if (do_gfx_mhz)
@ -768,7 +774,12 @@ delta_package(struct pkg_data *new, struct pkg_data *old)
old->pc10 = new->pc10 - old->pc10;
old->pkg_temp_c = new->pkg_temp_c;
old->gfx_rc6_ms = new->gfx_rc6_ms - old->gfx_rc6_ms;
/* flag an error when rc6 counter resets/wraps */
if (old->gfx_rc6_ms > new->gfx_rc6_ms)
old->gfx_rc6_ms = -1;
else
old->gfx_rc6_ms = new->gfx_rc6_ms - old->gfx_rc6_ms;
old->gfx_mhz = new->gfx_mhz;
DELTA_WRAP32(new->energy_pkg, old->energy_pkg);