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Message-ID: <20170914140531.GA10371@kernel.org> Date: Thu, 14 Sep 2017 11:05:31 -0300 From: Arnaldo Carvalho de Melo <acme@...nel.org> To: "Jin, Yao" <yao.jin@...ux.intel.com> Cc: jolsa@...nel.org, peterz@...radead.org, mingo@...hat.com, alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org, ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com Subject: Re: [PATCH v1 1/4] perf annotate: create a new hists to manage multiple events samples Em Thu, Sep 14, 2017 at 09:03:55AM +0800, Jin, Yao escreveu: > On 9/11/2017 9:33 AM, Jin, Yao wrote: > > On 9/8/2017 9:43 PM, Arnaldo Carvalho de Melo wrote: > >> Em Wed, Aug 16, 2017 at 06:18:33PM +0800, Jin Yao escreveu: > >>> An issue is found during using perf annotate. > >>> > >>> perf record -e cycles,branches ... > >>> perf annotate main --stdio > >>> > >>> The result only shows cycles. It should show both cycles and > >>> branches on the left side. It works with "--group", but need > >>> this to work even without groups. > >>> > >>> In current design, the hists is per event. So we need a new > >>> hists to manage the samples for multiple events and use a new > >>> hist_event data structure to save the map/symbol information > >>> for per event. > >> Humm, why do we need another hists? Don't we have one per evsel, don't > >> we have a evlist from where to get all of those evsels, can't we just > >> use that to add one column per evsel? > > I'm considering a case. > > Suppose we sample 2 events ("branches" and "cache-misses"). The samples of "branches" are hit in function A and the samples of "cache-misses" are hit in function B. > > > > The branches evsel has one hists and cache-misses evsel has another hists. > > > > The hists of branches evsel has one hist-entry which stands for the function A symbol. The hists of cache-misses evsel has one hist-entry which stands for the function B symbol. > > > > If we start to show the instructions in function B from cache-misses evsel, we will lose the function A. > > > > Because even if we get the branches evsel from the link in cache-misses evsel, but the function A is before function B and function B has been displayed yet, so the function A is lost. > > > > Considering the number of events can be greater than 2, the code will be much more complicated. So using a global hists should be an easy solution. > > Could the solution of using a new hists for multiple events be accepted? > > Or anything I should update in the patches? I'm not having time at this moment for doing a proper review, wait a bit more please. - Arnaldo
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