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From: Andres Freund <andres@anarazel.de>
To: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	alexander.shishkin@linux.intel.com, jolsa@kernel.org,
	Namhyung Kim <namhyung@kernel.org>,
	Quentin Monnet <quentin@isovalent.com>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	bpf@vger.kernel.org
Subject: Re: [perf-tools] Build-error in tools/perf/util/annotate.c with LLVM-14
Date: Sun, 3 Jul 2022 09:51:15 -0700	[thread overview]
Message-ID: <20220703165115.gox3hlwwdcnorcul@awork3.anarazel.de> (raw)
In-Reply-To: <CA+icZUVpr8ZeOKCj4zMMqbFT013KJz2T1csvXg+VSkdvJH1Ubw@mail.gmail.com>

Hi,

On 2022-07-03 13:54:41 +0200, Sedat Dilek wrote:
> Andres, you have some test-cases how you verified the built perf is OK?

I ran an intentionally expensive workload, monitored it with bpftrace, then
took a perf profile. Then annotated the bpf "function" and verified it looked
the same before / after, using a perf built in a container (and thus
compiling).


Similar with bpftool, I dumped a jited program with a bpftool built with /
without the patches (inside the container using nsenter for the version
without the patches, so I could build it, using nsenter -t $pid -m -p) and
compared both the json and non-json output before / after.

V=4; nsenter -t 847325 -m -p /usr/src/linux/tools/bpf/bpftool/bpftool -j -d prog dump jited id 22 > /tmp/22.jit.json.$V; nsenter -t 847325 -m -p /usr/src/linux/tools/bpf/bpftool/bpftool -d prog dump jited id 22 > /tmp/22.jit.txt.$V

and then diffed the results.


bpf_jit_disasm was harder, because bpf_jit_enable = 2 is broken currently. So
I gathered output in a VM from an older kernel, and used bpf_jit_disasm -f ...
before / after the patches.

Greetings,

Andres Freund

  parent reply	other threads:[~2022-07-03 16:51 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-03 10:57 [perf-tools] Build-error in tools/perf/util/annotate.c with LLVM-14 Sedat Dilek
2022-07-03 11:03 ` Sedat Dilek
2022-07-03 11:06   ` Sedat Dilek
2022-07-03 11:54     ` Sedat Dilek
2022-07-03 13:54       ` Arnaldo Carvalho de Melo
2022-07-03 16:54         ` Andres Freund
2022-07-03 17:46           ` Arnaldo Carvalho de Melo
2022-07-03 20:32             ` Sedat Dilek
2022-07-03 16:51       ` Andres Freund [this message]
2022-07-03 20:40         ` Sedat Dilek
2022-07-03 21:31           ` Andres Freund

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