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Message-ID: <20240604145742.5703d074@gandalf.local.home>
Date: Tue, 4 Jun 2024 14:57:42 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Mark Rutland <mark.rutland@....com>
Cc: Masami Hiramatsu <mhiramat@...nel.org>, linux-kernel@...r.kernel.org,
linux-trace-kernel@...r.kernel.org, Mathieu Desnoyers
<mathieu.desnoyers@...icios.com>, Andrew Morton
<akpm@...ux-foundation.org>, Alexei Starovoitov
<alexei.starovoitov@...il.com>, Florent Revest <revest@...omium.org>,
Martin KaFai Lau <martin.lau@...ux.dev>, bpf <bpf@...r.kernel.org>, Sven
Schnelle <svens@...ux.ibm.com>, Alexei Starovoitov <ast@...nel.org>, Jiri
Olsa <jolsa@...nel.org>, Arnaldo Carvalho de Melo <acme@...nel.org>, Daniel
Borkmann <daniel@...earbox.net>, Alan Maguire <alan.maguire@...cle.com>,
Peter Zijlstra <peterz@...radead.org>, Thomas Gleixner
<tglx@...utronix.de>, Guo Ren <guoren@...nel.org>
Subject: Re: [PATCH v3 00/27] function_graph: Allow multiple users for
function graph tracing
On Tue, 4 Jun 2024 18:04:22 +0100
Mark Rutland <mark.rutland@....com> wrote:
> > There may have been something arch specific that I'm unaware about. I'll
> > look at that deeper.
>
> It looks like e are lines in the trace that it doesn't expect:
>
> + cat trace
> + grep -v ^#
> + grep 970
> + wc -l
> + count_pid=0
> + cat trace
> + grep -v ^#
> + grep -v 970
> + wc -l
> + count_other=3
> + [ 0 -eq 0 -o 3 -ne 0 ]
> + fail PID filtering not working?
>
> ... where we expect that count_other to be 0.
>
> I hacked in a 'cat trace' just before the 'fail' and that shows:
>
> + cat trace
> # tracer: function_graph
> #
> # CPU DURATION FUNCTION CALLS
> # | | | | | | |
> 3) ! 143.685 us | kernel_clone();
> 3) ! 127.055 us | kernel_clone();
> 1) ! 127.170 us | kernel_clone();
> 3) ! 126.840 us | kernel_clone();
>
> I'm not sure if that's legitimate output the test is failing to account
> for or if that indicates a kernel-side issue.
Bah, I just ran the test.d/ftrace/func-filter-pid.tc and it fails too. This
did pass my other tests that do run ftracetests. Hmm, I just ran it on my
test box that does the tests and it passes there. I wonder if there's some
config option that makes it fail :-/
Well, now that I see it fail, I can investigate.
-- Steve
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