Messages in this thread | | | Date | Thu, 23 Mar 2023 16:31:21 -0400 | Subject | Re: [PATCH v2 8/9] perf metrics: Add has_optane literal | From | "Liang, Kan" <> |
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On 2023-03-23 3:20 p.m., Ian Rogers wrote: > Add literal so that if optane memory isn't installed we can record > fewer events.
I think we call it pmem (Persistent Memory) everywhere in the Linux code. Maybe we should use #has_pmem instead?
Thanks, Kan > 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/ > > Signed-off-by: Ian Rogers <irogers@google.com> > --- > tools/perf/util/expr.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c > index d46a1878bc9e..a43cdda0b044 100644 > --- a/tools/perf/util/expr.c > +++ b/tools/perf/util/expr.c > @@ -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_optane(void) > +{ > + static bool has_optane, cached; > + const char *sysfs = sysfs__mountpoint(); > + char path[PATH_MAX]; > + > + if (!cached) { > + snprintf(path, sizeof(path), "%s/firmware/acpi/tables/NFIT", sysfs); > + has_optane = access(path, F_OK) == 0; > + cached = true; > + } > + return has_optane ? 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_optane", literal)) { > + result = has_optane(); > + goto out; > + } > > pr_err("Unrecognized literal '%s'", literal); > out:
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