Messages in this thread Patch in this message | | | Date | Fri, 24 Mar 2023 00:22:17 -0700 | Subject | [PATCH v3 8/9] perf metrics: Add has_pmem literal | From | Ian Rogers <> |
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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/
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..bb6ddad7e021 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_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: -- 2.40.0.348.gf938b09366-goog
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