perf record: Add AUX area tracing Snapshot Mode support

Add a new option and support for Instruction Tracing Snapshot Mode.
When the new option is selected, no AUX area tracing data is captured
until a signal (SIGUSR2) is received.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1430404667-10593-10-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 76a141e..57dd57b 100644 (file)
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -259,6 +259,13 @@ 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.
 
+-S::
+--snapshot::
+Select AUX area tracing Snapshot Mode. This option is valid only with an
+AUX area tracing event. Optionally the number of bytes to capture per
+snapshot can be specified. In Snapshot Mode, trace data is captured only when
+signal SIGUSR2 is received.
+
 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 dbb2c02..5dfe913 100644 (file)
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -112,6 +112,32 @@ out:
        return rc;
 }
 
+static volatile int done;
+static volatile int signr = -1;
+static volatile int child_finished;
+static volatile int auxtrace_snapshot_enabled;
+static volatile int auxtrace_snapshot_err;
+static volatile int auxtrace_record__snapshot_started;
+
+static void sig_handler(int sig)
+{
+       if (sig == SIGCHLD)
+               child_finished = 1;
+       else
+               signr = sig;
+
+       done = 1;
+}
+
+static void record__sig_exit(void)
+{
+       if (signr == -1)
+               return;
+
+       signal(signr, SIG_DFL);
+       raise(signr);
+}
+
 #ifdef HAVE_AUXTRACE_SUPPORT
 
 static int record__process_auxtrace(struct perf_tool *tool,
@@ -167,6 +193,56 @@ static int record__auxtrace_mmap_read(struct record *rec,
        return 0;
 }
 
+static int record__auxtrace_mmap_read_snapshot(struct record *rec,
+                                              struct auxtrace_mmap *mm)
+{
+       int ret;
+
+       ret = auxtrace_mmap__read_snapshot(mm, rec->itr, &rec->tool,
+                                          record__process_auxtrace,
+                                          rec->opts.auxtrace_snapshot_size);
+       if (ret < 0)
+               return ret;
+
+       if (ret)
+               rec->samples++;
+
+       return 0;
+}
+
+static int record__auxtrace_read_snapshot_all(struct record *rec)
+{
+       int i;
+       int rc = 0;
+
+       for (i = 0; i < rec->evlist->nr_mmaps; i++) {
+               struct auxtrace_mmap *mm =
+                               &rec->evlist->mmap[i].auxtrace_mmap;
+
+               if (!mm->base)
+                       continue;
+
+               if (record__auxtrace_mmap_read_snapshot(rec, mm) != 0) {
+                       rc = -1;
+                       goto out;
+               }
+       }
+out:
+       return rc;
+}
+
+static void record__read_auxtrace_snapshot(struct record *rec)
+{
+       pr_debug("Recording AUX area tracing snapshot\n");
+       if (record__auxtrace_read_snapshot_all(rec) < 0) {
+               auxtrace_snapshot_err = -1;
+       } else {
+               auxtrace_snapshot_err = auxtrace_record__snapshot_finish(rec->itr);
+               if (!auxtrace_snapshot_err)
+                       auxtrace_snapshot_enabled = 1;
+       }
+}
+
 #else
 
 static inline
@@ -176,31 +252,19 @@ int record__auxtrace_mmap_read(struct record *rec __maybe_unused,
        return 0;
 }
 
-#endif
-
-static volatile int done = 0;
-static volatile int signr = -1;
-static volatile int child_finished = 0;
-
-static void sig_handler(int sig)
+static inline
+void record__read_auxtrace_snapshot(struct record *rec __maybe_unused)
 {
-       if (sig == SIGCHLD)
-               child_finished = 1;
-       else
-               signr = sig;
-
-       done = 1;
 }
 
-static void record__sig_exit(void)
+static inline
+int auxtrace_record__snapshot_start(struct auxtrace_record *itr __maybe_unused)
 {
-       if (signr == -1)
-               return;
-
-       signal(signr, SIG_DFL);
-       raise(signr);
+       return 0;
 }
 
+#endif
+
 static int record__open(struct record *rec)
 {
        char msg[512];
@@ -238,7 +302,8 @@ try_again:
        }
 
        if (perf_evlist__mmap_ex(evlist, opts->mmap_pages, false,
-                                opts->auxtrace_mmap_pages, false) < 0) {
+                                opts->auxtrace_mmap_pages,
+                                opts->auxtrace_snapshot_mode) < 0) {
                if (errno == EPERM) {
                        pr_err("Permission error mapping pages.\n"
                               "Consider increasing "
@@ -349,7 +414,7 @@ static int record__mmap_read_all(struct record *rec)
                        }
                }
 
-               if (mm->base &&
+               if (mm->base && !rec->opts.auxtrace_snapshot_mode &&
                    record__auxtrace_mmap_read(rec, mm) != 0) {
                        rc = -1;
                        goto out;
@@ -404,6 +469,8 @@ static void workload_exec_failed_signal(int signo __maybe_unused,
        child_finished = 1;
 }
 
+static void snapshot_sig_handler(int sig);
+
 static int __cmd_record(struct record *rec, int argc, const char **argv)
 {
        int err;
@@ -424,6 +491,10 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
        signal(SIGCHLD, sig_handler);
        signal(SIGINT, sig_handler);
        signal(SIGTERM, sig_handler);
+       if (rec->opts.auxtrace_snapshot_mode)
+               signal(SIGUSR2, snapshot_sig_handler);
+       else
+               signal(SIGUSR2, SIG_IGN);
 
        session = perf_session__new(file, false, tool);
        if (session == NULL) {
@@ -563,14 +634,27 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
                perf_evlist__enable(rec->evlist);
        }
 
+       auxtrace_snapshot_enabled = 1;
        for (;;) {
                int hits = rec->samples;
 
                if (record__mmap_read_all(rec) < 0) {
+                       auxtrace_snapshot_enabled = 0;
                        err = -1;
                        goto out_child;
                }
 
+               if (auxtrace_record__snapshot_started) {
+                       auxtrace_record__snapshot_started = 0;
+                       if (!auxtrace_snapshot_err)
+                               record__read_auxtrace_snapshot(rec);
+                       if (auxtrace_snapshot_err) {
+                               pr_err("AUX area tracing snapshot failed\n");
+                               err = -1;
+                               goto out_child;
+                       }
+               }
+
                if (hits == rec->samples) {
                        if (done || draining)
                                break;
@@ -593,10 +677,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
                 * disable events in this case.
                 */
                if (done && !disabled && !target__none(&opts->target)) {
+                       auxtrace_snapshot_enabled = 0;
                        perf_evlist__disable(rec->evlist);
                        disabled = true;
                }
        }
+       auxtrace_snapshot_enabled = 0;
 
        if (forks && workload_exec_errno) {
                char msg[STRERR_BUFSIZE];
@@ -1068,6 +1154,8 @@ struct option __record_options[] = {
        OPT_CALLBACK('k', "clockid", &record.opts,
        "clockid", "clockid to use for events, see clock_gettime()",
        parse_clockid),
+       OPT_STRING_OPTARG('S', "snapshot", &record.opts.auxtrace_snapshot_opts,
+                         "opts", "AUX area tracing Snapshot Mode", ""),
        OPT_END()
 };
 
@@ -1102,6 +1190,11 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
                        return err;
        }
 
+       err = auxtrace_parse_snapshot_options(rec->itr, &rec->opts,
+                                             rec->opts.auxtrace_snapshot_opts);
+       if (err)
+               return err;
+
        err = -ENOMEM;
 
        symbol__init(NULL);
@@ -1165,3 +1258,12 @@ out_symbol_exit:
        auxtrace_record__free(rec->itr);
        return err;
 }
+
+static void snapshot_sig_handler(int sig __maybe_unused)
+{
+       if (!auxtrace_snapshot_enabled)
+               return;
+       auxtrace_snapshot_enabled = 0;
+       auxtrace_snapshot_err = auxtrace_record__snapshot_start(record.itr);
+       auxtrace_record__snapshot_started = 1;
+}

diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index c2c677e..a171abb 100644 (file)
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -564,6 +564,17 @@ int itrace_parse_synth_opts(const struct option *opt __maybe_unused,
 }
 
 static inline
+int auxtrace_parse_snapshot_options(struct auxtrace_record *itr __maybe_unused,
+                                   struct record_opts *opts __maybe_unused,
+                                   const char *str)
+{
+       if (!str)
+               return 0;
+       pr_err("AUX area tracing not supported\n");
+       return -EINVAL;
+}
+
+static inline
 int auxtrace__process_event(struct perf_session *session __maybe_unused,
                            union perf_event *event __maybe_unused,
                            struct perf_sample *sample __maybe_unused,

diff --git a/tools/perf/util/parse-options.h b/tools/perf/util/parse-options.h
index 59561fd..367d8b8 100644 (file)
--- a/tools/perf/util/parse-options.h
+++ b/tools/perf/util/parse-options.h
@@ -123,6 +123,10 @@ struct option {
 #define OPT_LONG(s, l, v, h)        { .type = OPTION_LONG, .short_name = (s), .long_name = (l), .value = check_vtype(v, long *), .help = (h) }
 #define OPT_U64(s, l, v, h)         { .type = OPTION_U64, .short_name = (s), .long_name = (l), .value = check_vtype(v, u64 *), .help = (h) }
 #define OPT_STRING(s, l, v, a, h)   { .type = OPTION_STRING,  .short_name = (s), .long_name = (l), .value = check_vtype(v, const char **), (a), .help = (h) }
+#define OPT_STRING_OPTARG(s, l, v, a, h, d) \
+       { .type = OPTION_STRING,  .short_name = (s), .long_name = (l), \
+         .value = check_vtype(v, const char **), (a), .help = (h), \
+         .flags = PARSE_OPT_OPTARG, .defval = (intptr_t)(d) }
 #define OPT_STRING_NOEMPTY(s, l, v, a, h)   { .type = OPTION_STRING,  .short_name = (s), .long_name = (l), .value = check_vtype(v, const char **), (a), .help = (h), .flags = PARSE_OPT_NOEMPTY}
 #define OPT_DATE(s, l, v, h) \
        { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), .value = (v), .argh = "time", .help = (h), .callback = parse_opt_approxidate_cb }