Messages in this thread | | | Date | Thu, 17 Oct 2013 17:57:20 +0200 | Subject | Re: [PATCH v2] perf: disable PERF_RECORD_MMAP2 support | From | Stephane Eranian <> |
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On Thu, Oct 17, 2013 at 5:54 PM, David Ahern <dsahern@gmail.com> wrote: > On 10/17/13 8:28 AM, Stephane Eranian wrote: >> >> >> For now, we disable the extended MMAP record support (MMAP2). >> We have identified cases where it would not report the correct >> mapping information, clone(VM_CLONE) but with separate pids. >> We will revisit the support once we find a solution for this case. >> >> The patch changes the kernel to return EINVAL if attr->mmap2 >> is set. The patch also modifies the perf tool to use regular >> PERF_RECORD_MMAP >> for synthetic events and it also prevents the tool from requesting >> attr->mmap2 >> mode because the kernel would reject it. >> >> The support will be revisited once the kenrel interface is updated. > > > Why not disable mmap2 as well: > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > index 0ce9febf1ba0..289f34dbe970 100644 > --- a/tools/perf/util/evsel.c > +++ b/tools/perf/util/evsel.c > @@ -678,7 +678,7 @@ void perf_evsel__config(struct perf_evsel *evsel, > attr->sample_type |= PERF_SAMPLE_WEIGHT; > > attr->mmap = track; > - attr->mmap2 = track && !perf_missing_features.mmap2; > + /* attr->mmap2 = track && !perf_missing_features.mmap2; */ > attr->comm = track; > It is disabled automatically later on. I checked that. Wanted to minimize the changes.
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