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platform/x86: intel_pmc_core: transform Pkg C-state residency from TSC ticks into microseconds

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Refer to the Intel SDM Vol.4, the package C-state residency counters
of modern IA micro-architecture are all ticking in TSC frequency,
hence we can apply simple math to transform the ticks into microseconds.
i.e.,
residency (ms) = count / tsc_khz
residency (us) = count / tsc_khz * 1000

This also aligns to other sysfs debug entries of residency counter in
the same metric in microseconds, benefits reading and scripting.

v2: restore the accidentally deleted newline, no function change.
v3: apply kernel do_div() macro to calculate division

Signed-off-by: Harry Pan <harry.pan@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This commit is contained in:
Harry Pan 2019-06-19 16:28:01 +08:00 committed by Andy Shevchenko
parent 8e8fe446a9
commit c09c607131
1 changed files with 4 additions and 1 deletions
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5
drivers/platform/x86/intel_pmc_core.c
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@ -26,6 +26,7 @@
#include <asm/cpu_device_id.h>
#include <asm/intel-family.h>
#include <asm/msr.h>
#include <asm/tsc.h>
#include "intel_pmc_core.h"
@ -740,7 +741,9 @@ static int pmc_core_pkgc_show(struct seq_file *s, void *unused)
if (rdmsrl_safe(map[index].bit_mask, &pcstate_count))
continue;
seq_printf(s, "%-8s : 0x%llx\n", map[index].name,
pcstate_count *= 1000;
do_div(pcstate_count, tsc_khz);
seq_printf(s, "%-8s : %llu\n", map[index].name,
pcstate_count);
}