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Date: Fri, 4 Sep 2015 16:42:30 +0300 From: Adrian Hunter <adrian.hunter@...el.com> To: Arnaldo Carvalho de Melo <acme@...hat.com> Cc: Jiri Olsa <jolsa@...hat.com>, jolsa@...nel.org, mingo@...nel.org, kan.liang@...el.com, linux-kernel@...r.kernel.org Subject: Re: [PATCH] perf tools: Fix gaps propagating maps On 04/09/15 16:28, Arnaldo Carvalho de Melo wrote: > Em Fri, Sep 04, 2015 at 03:15:54PM +0300, Adrian Hunter escreveu: >> A perf_evsel is a selected event containing the perf_event_attr >> that is passed to perf_event_open(). A perf_evlist is a collection >> of perf_evsel's. A perf_evlist also has lists of cpus and threads >> (pids) on which to open the event. These lists are called 'maps' >> and this patch is about how those 'maps' are propagated from the >>> perf_evlist to the perf_evsels. > > Can't this be broken up in multiple patches, for instance this: Ok, might not be until next week though. > > int perf_evlist__create_maps(struct perf_evlist *evlist, struct > target *target) > { > + if (evlist->threads || evlist->cpus) > + return -1; > + Or you could just drop that chunk. > > Looks like a fix that could be separated. Also FOO__propagate(.., false) > to do the opposite of propagate seems confusing, how about > FOO__unpropagate() if that verb exists? :-) Ok > > > Also, when unpropagating, you do: > > if (evsel->cpus == evlist->cpus) { > cpu_map__put(evsel->cpus); > evsel->cpus = NULL; > } > > What if the PMU code _set_ it to the same cpus as in evlist->cpus, but > now we're unpropagating to set to another CPU, in this case we will be > changing the PMU setting with a new one. I.e. when a PMU sets it it > should be sticky, no? We are comparing the pointer, so that won't happen unless the PMU actually does evsel->cpus = evlist->cpus which seems unlikely. > > I.e. we would have to know, in the evsel, if evsel->cpus was set by the > PMU or any other future entity expecting this behaviour, so that we > don't touch it, i.e. testing (evsel->cpus != evlist->cpus) when > unpropagating doesn't seem to cut, right? I think the pointer comparison covers that. i.e. the pointers won't be the same even if the cpus are. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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