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Date: Fri, 1 Nov 2013 13:29:42 +0100
From: Jiri Olsa <jolsa@redhat.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@kernel.org>,
        Namhyung Kim <namhyung.kim@lge.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Stephane Eranian <eranian@google.com>,
        Rodrigo Campos <rodrigo@sdfg.com.ar>, Arun Sharma <asharma@fb.com>
Subject: Re: [PATCH 08/14] perf report: Cache cumulative callchains
Message-ID: <20131101122942.GD10041@krava.brq.redhat.com>
References: <1383202576-28141-1-git-send-email-namhyung@kernel.org>
 <1383202576-28141-9-git-send-email-namhyung@kernel.org>
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On Thu, Oct 31, 2013 at 03:56:10PM +0900, Namhyung Kim wrote:

SNIP

>  	 * double accounting.
> @@ -501,8 +528,29 @@ iter_add_next_cumulative_entry(struct add_entry_iter *iter,
>  {
>  	struct perf_evsel *evsel = iter->evsel;
>  	struct perf_sample *sample = iter->sample;
> +	struct cumulative_cache *ccache = iter->priv;
>  	struct hist_entry *he;
>  	int err = 0;
> +	int i;
> +
> +	/*
> +	 * Check if there's duplicate entries in the callchain.
> +	 * It's possible that it has cycles or recursive calls.
> +	 */
> +	for (i = 0; i < iter->curr; i++) {
> +		if (sort__has_sym) {
> +			if (ccache[i].sym == al->sym)
> +				return 0;
> +		} else {
> +			/* Not much we can do - just compare the dso. */
> +			if (ccache[i].dso == al->map->dso)
> +				return 0;
> +		}
> +	}

hum, do we want to prevent recursion totaly?
how about intended recursion?

also should the dso be checked together with sym?
because the symbol is defined like dso::sym

jirka