perf intel-pt: Use perf_pmu__scan_file_at() if possible

Intel-PT calls perf_pmu__scan_file() a lot, let's use relative address
when it accesses multiple files at one place.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230331202949.810326-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c
index 1e39a034cee989c3c06051d4294c70e00f7bcec9..2cff11de9d8a8ef539e3492f7150c68fa93bde34 100644 (file)
--- a/tools/perf/arch/x86/util/intel-pt.c
+++ b/tools/perf/arch/x86/util/intel-pt.c
@@ -194,16 +194,19 @@ static u64 intel_pt_default_config(struct perf_pmu *intel_pt_pmu)
        int pos = 0;
        u64 config;
        char c;
+       int dirfd;
+
+       dirfd = perf_pmu__event_source_devices_fd();
 
        pos += scnprintf(buf + pos, sizeof(buf) - pos, "tsc");
 
-       if (perf_pmu__scan_file(intel_pt_pmu, "caps/mtc", "%d",
-                               &mtc) != 1)
+       if (perf_pmu__scan_file_at(intel_pt_pmu, dirfd, "caps/mtc", "%d",
+                                  &mtc) != 1)
                mtc = 1;
 
        if (mtc) {
-               if (perf_pmu__scan_file(intel_pt_pmu, "caps/mtc_periods", "%x",
-                                       &mtc_periods) != 1)
+               if (perf_pmu__scan_file_at(intel_pt_pmu, dirfd, "caps/mtc_periods", "%x",
+                                          &mtc_periods) != 1)
                        mtc_periods = 0;
                if (mtc_periods) {
                        mtc_period = intel_pt_pick_bit(mtc_periods, 3);
@@ -212,13 +215,13 @@ static u64 intel_pt_default_config(struct perf_pmu *intel_pt_pmu)
                }
        }
 
-       if (perf_pmu__scan_file(intel_pt_pmu, "caps/psb_cyc", "%d",
-                               &psb_cyc) != 1)
+       if (perf_pmu__scan_file_at(intel_pt_pmu, dirfd, "caps/psb_cyc", "%d",
+                                  &psb_cyc) != 1)
                psb_cyc = 1;
 
        if (psb_cyc && mtc_periods) {
-               if (perf_pmu__scan_file(intel_pt_pmu, "caps/psb_periods", "%x",
-                                       &psb_periods) != 1)
+               if (perf_pmu__scan_file_at(intel_pt_pmu, dirfd, "caps/psb_periods", "%x",
+                                          &psb_periods) != 1)
                        psb_periods = 0;
                if (psb_periods) {
                        psb_period = intel_pt_pick_bit(psb_periods, 3);
@@ -227,8 +230,8 @@ static u64 intel_pt_default_config(struct perf_pmu *intel_pt_pmu)
                }
        }
 
-       if (perf_pmu__scan_file(intel_pt_pmu, "format/pt", "%c", &c) == 1 &&
-           perf_pmu__scan_file(intel_pt_pmu, "format/branch", "%c", &c) == 1)
+       if (perf_pmu__scan_file_at(intel_pt_pmu, dirfd, "format/pt", "%c", &c) == 1 &&
+           perf_pmu__scan_file_at(intel_pt_pmu, dirfd, "format/branch", "%c", &c) == 1)
                pos += scnprintf(buf + pos, sizeof(buf) - pos, ",pt,branch");
 
        pr_debug2("%s default config: %s\n", intel_pt_pmu->name, buf);
@@ -236,6 +239,7 @@ static u64 intel_pt_default_config(struct perf_pmu *intel_pt_pmu)
        intel_pt_parse_terms(intel_pt_pmu->name, &intel_pt_pmu->format, buf,
                             &config);
 
+       close(dirfd);
        return config;
 }
 
@@ -488,7 +492,7 @@ static void intel_pt_valid_str(char *str, size_t len, u64 valid)
        }
 }
 
-static int intel_pt_val_config_term(struct perf_pmu *intel_pt_pmu,
+static int intel_pt_val_config_term(struct perf_pmu *intel_pt_pmu, int dirfd,
                                    const char *caps, const char *name,
                                    const char *supported, u64 config)
 {
@@ -498,11 +502,11 @@ static int intel_pt_val_config_term(struct perf_pmu *intel_pt_pmu,
        u64 bits;
        int ok;
 
-       if (perf_pmu__scan_file(intel_pt_pmu, caps, "%llx", &valid) != 1)
+       if (perf_pmu__scan_file_at(intel_pt_pmu, dirfd, caps, "%llx", &valid) != 1)
                valid = 0;
 
        if (supported &&
-           perf_pmu__scan_file(intel_pt_pmu, supported, "%d", &ok) == 1 && !ok)
+           perf_pmu__scan_file_at(intel_pt_pmu, dirfd, supported, "%d", &ok) == 1 && !ok)
                valid = 0;
 
        valid |= 1;
@@ -531,37 +535,45 @@ out_err:
 static int intel_pt_validate_config(struct perf_pmu *intel_pt_pmu,
                                    struct evsel *evsel)
 {
-       int err;
+       int err, dirfd;
        char c;
 
        if (!evsel)
                return 0;
 
+       dirfd = perf_pmu__event_source_devices_fd();
+       if (dirfd < 0)
+               return dirfd;
+
        /*
         * If supported, force pass-through config term (pt=1) even if user
         * sets pt=0, which avoids senseless kernel errors.
         */
-       if (perf_pmu__scan_file(intel_pt_pmu, "format/pt", "%c", &c) == 1 &&
+       if (perf_pmu__scan_file_at(intel_pt_pmu, dirfd, "format/pt", "%c", &c) == 1 &&
            !(evsel->core.attr.config & 1)) {
                pr_warning("pt=0 doesn't make sense, forcing pt=1\n");
                evsel->core.attr.config |= 1;
        }
 
-       err = intel_pt_val_config_term(intel_pt_pmu, "caps/cycle_thresholds",
+       err = intel_pt_val_config_term(intel_pt_pmu, dirfd, "caps/cycle_thresholds",
                                       "cyc_thresh", "caps/psb_cyc",
                                       evsel->core.attr.config);
        if (err)
-               return err;
+               goto out;
 
-       err = intel_pt_val_config_term(intel_pt_pmu, "caps/mtc_periods",
+       err = intel_pt_val_config_term(intel_pt_pmu, dirfd, "caps/mtc_periods",
                                       "mtc_period", "caps/mtc",
                                       evsel->core.attr.config);
        if (err)
-               return err;
+               goto out;
 
-       return intel_pt_val_config_term(intel_pt_pmu, "caps/psb_periods",
+       err = intel_pt_val_config_term(intel_pt_pmu, dirfd, "caps/psb_periods",
                                        "psb_period", "caps/psb_cyc",
                                        evsel->core.attr.config);
+
+out:
+       close(dirfd);
+       return err;
 }
 
 static void intel_pt_config_sample_mode(struct perf_pmu *intel_pt_pmu,