Commit c3bf86f1 authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

perf metrics: Add has_pmem literal 

Add literal so that if nvdimms aren't installed we can record fewer
events.  The file detection mechanism was suggested by Dan Williams
<dan.j.williams@intel.com> in:

  https://lore.kernel.org/linux-perf-users/641bbe1eced26_1b98bb29440@dwillia2-xfh.jf.intel.com.notmuch/



Reviewed-by: default avatarKan Liang <kan.liang@linux.intel.com>
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Edward Baker <edward.baker@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Samantha Alt <samantha.alt@intel.com>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20230324072218.181880-2-irogers@google.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e559b6f5

tools/perf/util/expr.c

+19 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include "util/hashmap.h"

#include "smt.h"

#include "tsc.h"

#include <api/fs/fs.h>

#include <linux/err.h>

#include <linux/kernel.h>

#include <linux/zalloc.h>
@@ -400,6 +401,20 @@ double arch_get_tsc_freq(void) 
}

#endif



static double has_pmem(void)

{

	static bool has_pmem, cached;

	const char *sysfs = sysfs__mountpoint();

	char path[PATH_MAX];



	if (!cached) {

		snprintf(path, sizeof(path), "%s/firmware/acpi/tables/NFIT", sysfs);

		has_pmem = access(path, F_OK) == 0;

		cached = true;

	}

	return has_pmem ? 1.0 : 0.0;

}



double expr__get_literal(const char *literal, const struct expr_scanner_ctx *ctx)

{

	const struct cpu_topology *topology;
@@ -449,6 +464,10 @@ double expr__get_literal(const char *literal, const struct expr_scanner_ctx *ctx 
		result = perf_pmu__cpu_slots_per_cycle();

		goto out;

	}

	if (!strcmp("#has_pmem", literal)) {

		result = has_pmem();

		goto out;

	}



	pr_err("Unrecognized literal '%s'", literal);

out: