From: Peter Zijlstra <pet...@infradead.org>

Teach perf-record about the new perf_event_attr:{use_+clockid, clockid}
fields. Add a simple parameter to set the clock (if any) to be used for
the events to be recorded into the dat file.

Incorporated improvements suggested by from David Ahern <dsah...@gmail.com>
on LKML.

Signed-off-by: Peter Zijlstra <pet...@infradead.org>
---
 tools/perf/Documentation/perf-record.txt |  7 +++
 tools/perf/builtin-record.c              | 78 ++++++++++++++++++++++++++++++++
 tools/perf/perf.h                        |  1 +
 tools/perf/util/evsel.c                  | 31 ++++++++++++-
 tools/perf/util/header.c                 |  2 +
 5 files changed, 118 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-record.txt 
b/tools/perf/Documentation/perf-record.txt
index 355c4f5..4847a79 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -250,6 +250,13 @@ is off by default.
 --running-time::
 Record running and enabled time for read events (:S)
 
+-k::
+--clockid::
+Sets the clock id to use for the various time fields in the perf_event_type
+records. See clock_gettime(). In particular CLOCK_MONOTONIC and
+CLOCK_MONOTONIC_RAW are supported, some events might also allow
+CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI.
+
 SEE ALSO
 --------
 linkperf:perf-stat[1], linkperf:perf-list[1]
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 18aad239..fc42a9a 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -711,6 +711,80 @@ static int perf_record_config(const char *var, const char 
*value, void *cb)
        return perf_default_config(var, value, cb);
 }
 
+struct clockid_map {
+       const char *name;
+       int clockid;
+};
+
+#define CLOCKID_MAP(n, c)      \
+       { .name = n, .clockid = (c), }
+
+#define CLOCKID_END    { .name = NULL, }
+
+/*
+ * Doesn't appear to have made it into userspace so define here if missing.
+ */
+#ifndef CLOCK_TAI
+#define CLOCK_TAI 11
+#endif
+
+static const struct clockid_map clockids[] = {
+       /* available for all events, NMI safe */
+       CLOCKID_MAP("monotonic", CLOCK_MONOTONIC),
+       CLOCKID_MAP("monotonic_raw", CLOCK_MONOTONIC_RAW),
+
+       /* available for some events */
+       CLOCKID_MAP("realtime", CLOCK_REALTIME),
+       CLOCKID_MAP("boottime", CLOCK_BOOTTIME),
+       CLOCKID_MAP("tai", CLOCK_TAI),
+
+       /* available for the lazy */
+       CLOCKID_MAP("mono", CLOCK_MONOTONIC),
+       CLOCKID_MAP("raw", CLOCK_MONOTONIC_RAW),
+       CLOCKID_MAP("real", CLOCK_REALTIME),
+
+
+       CLOCKID_END,
+};
+
+static int parse_clockid(const struct option *opt, const char *str, int unset)
+{
+       clockid_t *clk = (clockid_t *)opt->value;
+       const struct clockid_map *cm;
+       const char *ostr = str;
+
+       if (unset) {
+               *clk = -1;
+               return 0;
+       }
+
+       /* no arg passed */
+       if (!str)
+               return 0;
+
+       /* no setting it twice */
+       if (*clk != -1)
+               return -1;
+
+       /* if its a number, we're done */
+       if (sscanf(str, "%d", clk) == 1)
+               return 0;
+
+       /* allow a "CLOCK_" prefix to the name */
+       if (!strncasecmp(str, "CLOCK_", 6))
+               str += 6;
+
+       for (cm = clockids; cm->name; cm++) {
+               if (!strcasecmp(str, cm->name)) {
+                       *clk = cm->clockid;
+                       return 0;
+               }
+       }
+
+       ui__warning("unknown clockid %s, check man page\n", ostr);
+       return -1;
+}
+
 static const char * const __record_usage[] = {
        "perf record [<options>] [<command>]",
        "perf record [<options>] -- <command> [<options>]",
@@ -739,6 +813,7 @@ static struct record record = {
                        .uses_mmap   = true,
                        .default_per_cpu = true,
                },
+               .clockid             = -1,
        },
        .tool = {
                .sample         = process_sample_event,
@@ -842,6 +917,9 @@ struct option __record_options[] = {
                    "Sample machine registers on interrupt"),
        OPT_BOOLEAN(0, "running-time", &record.opts.running_time,
                    "Record running/enabled time of read (:S) events"),
+       OPT_CALLBACK('k', "clockid", &record.opts.clockid,
+       "clockid", "clockid to use for events, see clock_gettime()",
+       parse_clockid),
        OPT_END()
 };
 
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index c38a085..275c0c5 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -62,6 +62,7 @@ struct record_opts {
        u64          user_interval;
        bool         sample_transaction;
        unsigned     initial_delay;
+       clockid_t    clockid;
 };
 
 struct option;
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 358e595..820e789 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -32,6 +32,7 @@ static struct {
        bool exclude_guest;
        bool mmap2;
        bool cloexec;
+       bool clockid;
 } perf_missing_features;
 
 static int perf_evsel__no_extra_init(struct perf_evsel *evsel __maybe_unused)
@@ -761,6 +762,12 @@ void perf_evsel__config(struct perf_evsel *evsel, struct 
record_opts *opts)
                attr->disabled = 0;
                attr->enable_on_exec = 0;
        }
+
+       if (opts->clockid >= 0) {
+               attr->use_clockid = 1;
+               attr->clockid = opts->clockid;
+       } else
+               attr->clockid = -1;
 }
 
 static int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int 
nthreads)
@@ -1044,6 +1051,8 @@ static size_t perf_event_attr__fprintf(struct 
perf_event_attr *attr, FILE *fp)
        ret += PRINT_ATTR2(exclude_host, exclude_guest);
        ret += PRINT_ATTR2N("excl.callchain_kern", exclude_callchain_kernel,
                            "excl.callchain_user", exclude_callchain_user);
+       ret += __PRINT_ATTR("%u",,use_clockid);
+
 
        ret += PRINT_ATTR_U32(wakeup_events);
        ret += PRINT_ATTR_U32(wakeup_watermark);
@@ -1056,6 +1065,7 @@ static size_t perf_event_attr__fprintf(struct 
perf_event_attr *attr, FILE *fp)
        ret += PRINT_ATTR_X64(sample_regs_user);
        ret += PRINT_ATTR_U32(sample_stack_user);
        ret += PRINT_ATTR_X64(sample_regs_intr);
+       ret += PRINT_ATTR_U32(clockid);
 
        ret += fprintf(fp, "%.60s\n", graph_dotted_line);
 
@@ -1122,6 +1132,16 @@ static int __perf_evsel__open(struct perf_evsel *evsel, 
struct cpu_map *cpus,
                                goto try_fallback;
                        }
                        set_rlimit = NO_CHANGE;
+
+                       /*
+                        * If we succeeded but had to kill clockid, fail and
+                        * have perf_evsel__open_strerror() print us a nice
+                        * error.
+                        */
+                       if (perf_missing_features.clockid) {
+                               err = -EINVAL;
+                               goto out_close;
+                       }
                }
        }
 
@@ -1155,7 +1175,10 @@ static int __perf_evsel__open(struct perf_evsel *evsel, 
struct cpu_map *cpus,
        if (err != -EINVAL || cpu > 0 || thread > 0)
                goto out_close;
 
-       if (!perf_missing_features.cloexec && (flags & PERF_FLAG_FD_CLOEXEC)) {
+       if (!perf_missing_features.clockid && evsel->attr.use_clockid) {
+               perf_missing_features.clockid = true;
+               goto fallback_missing_features;
+       } else if (!perf_missing_features.cloexec && (flags & 
PERF_FLAG_FD_CLOEXEC)) {
                perf_missing_features.cloexec = true;
                goto fallback_missing_features;
        } else if (!perf_missing_features.mmap2 && evsel->attr.mmap2) {
@@ -2080,6 +2103,8 @@ int perf_evsel__fprintf(struct perf_evsel *evsel,
                if_print(wakeup_events);
                if_print(bp_type);
                if_print(branch_sample_type);
+               if_print(clockid);
+
        }
 out:
        fputc('\n', fp);
@@ -2158,6 +2183,10 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, 
struct target *target,
        "The PMU counters are busy/taken by another profiler.\n"
        "We found oprofile daemon running, please stop it and try again.");
                break;
+       case EINVAL:
+               if (perf_missing_features.clockid)
+                       return scnprintf(msg, size, "%d %s", 
evsel->attr.clockid, "clockid not supported.");
+               break;
        default:
                break;
        }
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index fb43215..164441a 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1098,6 +1098,8 @@ static void print_event_desc(struct perf_header *ph, int 
fd, FILE *fp)
                        }
                        fprintf(fp, " }");
                }
+               fprintf(fp, ", clockid = %d", evsel->attr.clockid);
+
 
                fputc('\n', fp);
        }
-- 
1.9.1

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