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SubjectRe: [PATCH v2 2/3] perf unwind: fix libunwind when tid != pid
Em Thu, Aug 15, 2019 at 04:10:35PM +0200, Jiri Olsa escreveu:
> On Thu, Aug 15, 2019 at 11:01:45AM +0100, John Keeping wrote:
> > Commit e5adfc3e7e77 ("perf map: Synthesize maps only for thread group
> > leader") changed the recording side so that we no longer get mmap events
> > for threads other than the thread group leader (when synthesising these
> > events for threads which exist before perf is started).
> >
> > When a file recorded after this change is loaded, the lack of mmap
> > records mean that unwinding is not set up for any other threads.
> >
> > This can be seen in a simple record/report scenario:
> >
> > perf record --call-graph=dwarf -t $TID
> > perf report
> >
> > If $TID is a process ID then the report will show call graphs, but if
> > $TID is a secondary thread the output is as if --call-graph=none was
> > specified.
>
> great, mucch clearler now
>
> >
> > Following the rationale in that commit, move the libunwind fields into
> > struct map_groups and update the libunwind functions to take this
> > instead of the struct thread. This is only required for
> > unwind__finish_access which must now be called from map_groups__delete
> > and the others are changed for symmetry.
> >
> > Note that unwind__get_entries keeps the thread argument since it is
> > required for symbol lookup and the libdw unwind provider uses the thread
> > ID.
> >
> > Fixes: e5adfc3e7e77 ("perf map: Synthesize maps only for thread group leader")
>
> for all 3 patches
>
> Reviewed-by: Jiri Olsa <jolsa@kernel.org>


Thanks, applied.

- Arnaldo

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