Re: [PATCH v2] perf: libdw support for powerpc [ping]
From: Arnaldo Carvalho de Melo <acme@kernel.org>
Date: 2017-06-21 01:06:41
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Em Thu, Jun 15, 2017 at 01:16:32PM +0200, Mark Wielaard escreveu:
On Thu, 2017-06-15 at 10:46 +0200, Milian Wolff wrote:quoted
Just a quick question: Have you guys applied my recent patch: commit 5ea0416f51cc93436bbe497c62ab49fd9cb245b6 Author: Milian Wolff [off-list ref] Date: Thu Jun 1 23:00:21 2017 +0200 perf report: Include partial stacks unwound with libdw So far the whole stack was thrown away when any error occurred before the maximum stack depth was unwound. This is actually a very common scenario though. The stacks that got unwound so far are still interesting. This removes a large chunk of differences when comparing perf script output for libunwind and libdw perf unwinding. If not, then this could explain the issue you are seeing.Thanks! No, I didn't have that patch (*) yet. It makes a huge difference. With that, Paolo's patch and the elfutils libdw powerpc64 fallback unwinder patch, it looks like I get user stack traces for everything now on ppc64le.
Can I take that as a Tested-by: you? - Arnaldo
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Cheers, Mark (*) It just this one-liner, but what a difference that makes:--- a/tools/perf/util/unwind-libdw.c +++ b/tools/perf/util/unwind-libdw.c@@ -224,7 +224,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui); - if (err && !ui->max_stack) + if (err && ui->max_stack != max_stack) err = 0; /*