| Date | Fri, 26 Dec 2014 09:27:05 -0700 | From | David Ahern <> | Subject | Re: [PATCH 02/37] perf record: Use a software dummy event to track task/mmap events |
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On 12/24/14 12:14 AM, Namhyung Kim wrote: > Prepend a software dummy event into evlist to track task/comm/mmap > events separately. This is a preparation of multi-file/thread support > which will come later.
Are you are making this the first event because of how perf internals are coded -- that the first event tracks tasks events? With the tracking bit in evsel you should not need to do that. Is there another reason?
---8<---
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c > index cfbe2b99b9aa..72dff295237e 100644 > --- a/tools/perf/util/evlist.c > +++ b/tools/perf/util/evlist.c > @@ -193,6 +193,44 @@ int perf_evlist__add_default(struct perf_evlist *evlist) > return -ENOMEM; > } > > +int perf_evlist__prepend_dummy(struct perf_evlist *evlist) > +{ > + struct perf_event_attr attr = { > + .type = PERF_TYPE_SOFTWARE, > + .config = PERF_COUNT_SW_DUMMY, > + }; > + struct perf_evsel *evsel, *pos; > + > + event_attr_init(&attr); > + > + evsel = perf_evsel__new(&attr); > + if (evsel == NULL) > + goto error; > + > + /* use strdup() because free(evsel) assumes name is allocated */ > + evsel->name = strdup("dummy"); > + if (!evsel->name) > + goto error_free; > + > + list_for_each_entry(pos, &evlist->entries, node) { > + pos->idx += 1; > + pos->tracking = false; > + } > + > + list_add(&evsel->node, &evlist->entries); > + evsel->idx = 0; > + evsel->tracking = true;
perf_evlist__set_tracking_event()?
David
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