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From: Matthew Wilcox <willy@infradead.org>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Ian Rogers <irogers@google.com>, Jiri Olsa <jolsa@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>, Hao Luo <haoluo@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	bpf@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-perf-users@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Stanislav Fomichev <sdf@google.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Namhyung Kim <namhyung@gmail.com>,
	Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCHv3 bpf-next 0/9] mm/bpf/perf: Store build id in file object
Date: Fri, 17 Mar 2023 03:51:15 +0000	[thread overview]
Message-ID: <ZBPjs1b8crUv4ur6@casper.infradead.org> (raw)
In-Reply-To: <CAEf4BzYgyGTVv=cDwaW+DBke1uk_aLCg3CB_9W6+9tkS8Nyn_Q@mail.gmail.com>

On Thu, Mar 16, 2023 at 02:51:52PM -0700, Andrii Nakryiko wrote:
> Yep, Meta is also capturing stack traces with build ID as well, if
> possible. Build IDs help with profiling short-lived processes which
> exit before the profiling session is done and user-space tooling is
> able to collect /proc/<pid>/maps contents (which is what Ian is
> referring to here). But also build ID allows to offload more of the
> expensive stack symbolization process (converting raw memory addresses
> into human readable function+offset+file path+line numbers
> information) to dedicated remote servers, by allowing to cache and
> reuse preprocessed DWARF/ELF information based on build ID.
> 
> I believe perf tool is also using build ID, so any tool relying on
> perf capturing full and complete profiling data for system-wide
> performance analysis would benefit as well.
> 
> Generally speaking, there is a whole ecosystem built on top of
> assumption that binaries have build ID and profiling tooling is able
> to provide more value if those build IDs are more reliably collected.
> Which ultimately benefits the entire open-source ecosystem by allowing
> people to spot issues (not necessarily just performance, it could be
> correctness issues as well) more reliably, fix them, and benefit every
> user.

But build IDs are _generally_ available.  The only problem (AIUI)
is when you're trying to examine the contents of one container from
another container.  And to solve that problem, you're imposing a cost
on everybody else with (so far) pretty vague justifications.  I really
don't like to see you growing struct file for this (nor struct inode,
nor struct vm_area_struct).  It's all quite unsatisfactory and I don't
have a good suggestion.

  reply	other threads:[~2023-03-17  3:51 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-16 17:01 [PATCHv3 bpf-next 0/9] mm/bpf/perf: Store build id in file object Jiri Olsa
2023-03-16 17:01 ` [PATCHv3 bpf-next 1/9] mm: " Jiri Olsa
2023-03-16 22:07   ` Andrii Nakryiko
2023-03-16 17:01 ` [PATCHv3 bpf-next 2/9] perf: Use file object build id in perf_event_mmap_event Jiri Olsa
2023-03-16 17:01 ` [PATCHv3 bpf-next 3/9] bpf: Use file object build id in stackmap Jiri Olsa
2023-03-16 22:07   ` Andrii Nakryiko
2023-03-16 17:01 ` [PATCHv3 bpf-next 4/9] bpf: Switch BUILD_ID_SIZE_MAX to enum Jiri Olsa
2023-03-16 22:07   ` Andrii Nakryiko
2023-03-16 17:01 ` [PATCHv3 bpf-next 5/9] selftests/bpf: Add read_buildid function Jiri Olsa
2023-03-16 22:23   ` Andrii Nakryiko
2023-03-30 22:05     ` Jiri Olsa
2023-03-16 17:01 ` [PATCHv3 bpf-next 6/9] selftests/bpf: Add err.h header Jiri Olsa
2023-03-16 22:24   ` Andrii Nakryiko
2023-03-16 17:01 ` [PATCHv3 bpf-next 7/9] selftests/bpf: Replace extract_build_id with read_build_id Jiri Olsa
2023-03-16 17:01 ` [PATCHv3 bpf-next 8/9] selftests/bpf: Add iter_task_vma_buildid test Jiri Olsa
2023-03-16 22:31   ` Andrii Nakryiko
2023-03-16 17:01 ` [PATCHv3 bpf-next 9/9] selftests/bpf: Add file_build_id test Jiri Olsa
2023-03-16 19:59   ` Daniel Borkmann
2023-03-16 22:36   ` Andrii Nakryiko
2023-03-16 17:34 ` [PATCHv3 bpf-next 0/9] mm/bpf/perf: Store build id in file object Matthew Wilcox
2023-03-16 17:50   ` Ian Rogers
2023-03-16 21:51     ` Andrii Nakryiko
2023-03-17  3:51       ` Matthew Wilcox [this message]
2023-03-17 16:33         ` Andrii Nakryiko
2023-03-17 21:14           ` Al Viro
2023-03-17 21:21             ` Al Viro
2023-03-18  6:08               ` Andrii Nakryiko
2023-03-18  8:34                 ` Jiri Olsa
2023-03-18  8:33   ` Jiri Olsa
2023-03-18 15:16     ` Matthew Wilcox
2023-03-18 17:40       ` Jiri Olsa
2023-03-22 15:45       ` Arnaldo Carvalho de Melo
2023-03-31 18:19         ` Andrii Nakryiko
2023-03-31 18:36           ` Matthew Wilcox
2023-03-31 20:27             ` Andrii Nakryiko

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