Re: [PATCH V6 08/17] perf tools: Add Intel PT support

From: Arnaldo Carvalho de Melo
Date: Thu Jun 25 2015 - 20:10:39 EST


Em Thu, Jun 25, 2015 at 08:56:34PM -0300, Arnaldo Carvalho de Melo escreveu:
> Will do the same tests with intel_pt as well, on a remote machine, add examples
> to the changeset logs and everything going well, aim for pushing for Ingo soon,

So, I asked for callchains, with:

perf record -g -e intel_bts// ls

And it got stuck somewhere, then I did a perf top to see where it was,
and got to:

96.24% perf [.] intel_bts_process_queue

Annotating I get to:

1.17 â1a0:âââmov 0x8(%r13),%rdx
â â test %rdx,%rdx
98.83 â âââje 1a0


Which is an endless loop! Source code for intel_bts_process_buffer(),
inlined there:

while (sz > sizeof(struct branch)) {
if (!branch->from && !branch->to)
continue;
err = intel_bts_synth_branch_sample(btsq, branch);
if (err)
break;
branch += 1;
sz -= sizeof(struct branch);
}

Can you fix this, please, so that I can fold it into where it was
introduced, namely:

commit 439ad895a2aecea09416206f023336297cc72efe
Author: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Date: Fri May 29 16:33:39 2015 +0300

perf tools: Add Intel BTS support

- Arnaldo
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