Commit c09c6071 authored Jun 19, 2019 by Harry Pan Committed by Andy Shevchenko Jul 03, 2019

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



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>

parent 8e8fe446

drivers/platform/x86/intel_pmc_core.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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);
		}