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Date: Tue, 19 May 2015 12:12:30 +0200
From: Jiri Olsa <jolsa@redhat.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
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        Andi Kleen <andi@firstfloor.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 34/40] perf report: Parallelize perf report using
 multi-thread
Message-ID: <20150519101230.GC22060@krava.redhat.com>
References: <1431909055-21442-1-git-send-email-namhyung@kernel.org>
 <1431909055-21442-35-git-send-email-namhyung@kernel.org>
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On Mon, May 18, 2015 at 09:30:49AM +0900, Namhyung Kim wrote:

SNIP

> +
> +int perf_session__process_events_mt(struct perf_session *session, void *arg)
> +{
> +	struct perf_data_file *file = session->file;
> +	struct perf_evlist *evlist = session->evlist;
> +	struct perf_evsel *evsel;
> +	u64 nr_entries = 0;
> +	struct perf_tool *tool = session->tool;
> +	struct perf_session *mt_sessions = NULL;
> +	struct perf_tool_mt *mt_tools = NULL;
> +	struct perf_session *ms;
> +	struct perf_tool_mt *mt;
> +	pthread_t *th_id;
> +	int err, i, k;
> +	int nr_index = session->header.nr_index;
> +	u64 size = perf_data_file__size(file);
> +

SNIP

> +
> +	for (i = 1; i < nr_index; i++) {
> +		mt = &mt_tools[i];
> +
> +		evlist__for_each(evlist, evsel) {
> +			struct hists *hists = evsel__hists(evsel);
> +
> +			if (perf_evsel__is_dummy_tracking(evsel))
> +				continue;
> +
> +			hists__mt_resort(hists, &mt->hists[evsel->idx]);
> +
> +			/* Non-group events are considered as leader */
> +			if (symbol_conf.event_group &&
> +			    !perf_evsel__is_group_leader(evsel)) {
> +				struct hists *leader_hists;
> +
> +				leader_hists = evsel__hists(evsel->leader);
> +				hists__match(leader_hists, hists);
> +				hists__link(leader_hists, hists);

hum, could you please describe/comment on why is this needed?

thanks,
jirka