linux-kernel - Re: [PATCHv3 00/12] perf tools: Display eBPF code in intel

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Message-ID: <20190530120709.GA3669@krava>
Date:   Thu, 30 May 2019 14:07:10 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Leo Yan <leo.yan@...aro.org>
Cc:     Jiri Olsa <jolsa@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Stanislav Fomichev <sdf@...ichev.me>,
        Song Liu <songliubraving@...com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCHv3 00/12] perf tools: Display eBPF code in intel_pt trace

On Thu, May 30, 2019 at 06:54:39PM +0800, Leo Yan wrote:
> Hi Jiri,
> 
> On Wed, May 08, 2019 at 03:19:58PM +0200, Jiri Olsa wrote:
> > hi,
> > this patchset adds dso support to read and display
> > bpf code in intel_pt trace output. I had to change
> > some of the kernel maps processing code, so hopefully
> > I did not break too many things ;-)
> > 
> > It's now possible to see bpf code flow via:
> > 
> >   # perf-with-kcore record pt -e intel_pt//ku -- sleep 1
> >   # perf-with-kcore script pt --insn-trace --xed
> 
> This is very interesting work for me!
> 
> I want to verify this feature with Arm CoreSight trace, I have one
> question so that I have more direction for the tesing:
> 
> What's the bpf program you are suing for the testing?  e.g. some
> testing program under the kernel's folder $kernel/samples/bpf?
> Or you uses perf command to launch bpf program?

for this I was using tools/testing/selftests/bpf/test_verifier

I isolated some tests and ran the perf on top of them, like:

  # perf-with-kcore record pt -e intel_pt//ku -- ./test_verifier ...

I had to add some small sleep before the test_verifier exit,
so the perf bpf thread could catch up and download the program
details before test_verifier exited.

jirka

> 
> [...]
> 
> Thanks
> Leo Yan