Messages in this thread Patch in this message | | | From | Arnaldo Carvalho de Melo <> | Subject | [PATCH 3/3] perf tools: Fix synthesizing tracepoint names from the perf.data headers | Date | Wed, 13 Jun 2012 12:29:27 -0300 |
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From: Arnaldo Carvalho de Melo <acme@redhat.com>
We need to use the per event info snapshoted at record time to synthesize the events name, so do it just after reading the perf.data headers, when we already processed the /sys events data, otherwise we'll end up using the local /sys that only by sheer luck will have the same tracepoint ID -> real event association.
Example:
# uname -a Linux felicio.ghostprotocols.net 3.4.0-rc5+ #1 SMP Sat May 19 15:27:11 BRT 2012 x86_64 x86_64 x86_64 GNU/Linux # perf record -e sched:sched_switch usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.015 MB perf.data (~648 samples) ] # cat /t/events/sched/sched_switch/id 279 # perf evlist -v sched:sched_switch: sample_freq=1, type: 2, config: 279, size: 80, sample_type: 1159, read_format: 7, disabled: 1, inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1 #
So on the above machine the sched:sched_switch has tracepoint id 279, but on the machine were we'll analyse it it has a different id:
$ cat /t/events/sched/sched_switch/id 56 $ perf evlist -i /tmp/perf.data kmem:mm_balancedirty_writeout $ cat /t/events/kmem/mm_balancedirty_writeout/id 279
With this fix:
$ perf evlist -i /tmp/perf.data sched:sched_switch
Reported-by: Dmitry Antipov <dmitry.antipov@linaro.org> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-auwks8fpuhmrdpiefs55o5oz@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/util/header.c | 32 ++++++++++++++++++++++++++++++++ 1 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 4f9b247..e909d43 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -2093,6 +2093,35 @@ static int read_attr(int fd, struct perf_header *ph, return ret <= 0 ? -1 : 0; } +static int perf_evsel__set_tracepoint_name(struct perf_evsel *evsel) +{ + struct event_format *event = trace_find_event(evsel->attr.config); + char bf[128]; + + if (event == NULL) + return -1; + + snprintf(bf, sizeof(bf), "%s:%s", event->system, event->name); + evsel->name = strdup(bf); + if (event->name == NULL) + return -1; + + return 0; +} + +static int perf_evlist__set_tracepoint_names(struct perf_evlist *evlist) +{ + struct perf_evsel *pos; + + list_for_each_entry(pos, &evlist->entries, node) { + if (pos->attr.type == PERF_TYPE_TRACEPOINT && + perf_evsel__set_tracepoint_name(pos)) + return -1; + } + + return 0; +} + int perf_session__read_header(struct perf_session *session, int fd) { struct perf_header *header = &session->header; @@ -2174,6 +2203,9 @@ int perf_session__read_header(struct perf_session *session, int fd) lseek(fd, header->data_offset, SEEK_SET); + if (perf_evlist__set_tracepoint_names(session->evlist)) + goto out_delete_evlist; + header->frozen = 1; return 0; out_errno: -- 1.7.1
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