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From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@kernel.org>, lkml <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Michael Petlan <mpetlan@redhat.com>,
	Song Liu <songliubraving@fb.com>, Ian Rogers <irogers@google.com>,
	Stephane Eranian <eranian@google.com>,
	Alexey Budankov <alexey.budankov@linux.intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [PATCH 03/24] perf: Add build id data in mmap2 event
Date: Tue, 10 Nov 2020 12:25:46 -0300	[thread overview]
Message-ID: <20201110152546.GB348806@kernel.org> (raw)
In-Reply-To: <20201110122232.GH2594@hirez.programming.kicks-ass.net>

Em Tue, Nov 10, 2020 at 01:22:32PM +0100, Peter Zijlstra escreveu:
> On Tue, Nov 10, 2020 at 08:54:26AM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Tue, Nov 10, 2020 at 09:07:16AM +0100, Peter Zijlstra escreveu:
> > > On Mon, Nov 09, 2020 at 10:53:54PM +0100, Jiri Olsa wrote:
> > > > Adding support to carry build id data in mmap2 event.

> > > > The build id data replaces maj/min/ino/ino_generation
> > > > fields, whichc are also used to identify map's binary,
> > > > so it's ok to replace them with build id data:

> > > >   union {
> > > >           struct {
> > > >                   u32       maj;
> > > >                   u32       min;
> > > >                   u64       ino;
> > > >                   u64       ino_generation;
> > > >           };
> > > >           struct {
> > > >                   u8        build_id[20];
> > > >                   u8        build_id_size;

> > > What's the purpose of a size field for a fixed size array? Also, I'd
> > > flip the order of these fields, first have the size and then the array.

> > There can be different types of build-ids, with different sizes,
> > flipping the order of the fields is indeed sensible, as we could then
> > support even larger build_ids if the need arises :)

> 3 whole bytes.. whooo!

Hey, I agreed with you, flip the order of the fields, right? :-)

- Arnaldo

  reply	other threads:[~2020-11-10 15:25 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-09 21:53 [PATCH 00/24] perf: Add mmap2 build id support Jiri Olsa
2020-11-09 21:53 ` [PATCH 01/24] bpf: Move stack_map_get_build_id into lib Jiri Olsa
2020-11-09 21:53 ` [PATCH 02/24] bpf: Add build_id_parse_size function Jiri Olsa
2020-11-10  0:15   ` Alexei Starovoitov
2020-11-10 10:01     ` Jiri Olsa
2020-11-09 21:53 ` [PATCH 03/24] perf: Add build id data in mmap2 event Jiri Olsa
2020-11-10  8:07   ` Peter Zijlstra
2020-11-10 10:08     ` Jiri Olsa
2020-11-10 11:54     ` Arnaldo Carvalho de Melo
2020-11-10 12:22       ` Peter Zijlstra
2020-11-10 15:25         ` Arnaldo Carvalho de Melo [this message]
2020-11-10  8:28   ` Peter Zijlstra
2020-11-10 10:10     ` Jiri Olsa
2020-11-10 18:23       ` Jiri Olsa
2020-11-10 18:55         ` Arnaldo Carvalho de Melo
2020-11-11 15:54           ` Jiri Olsa
2020-11-13  4:29   ` Namhyung Kim
2020-11-13 11:01     ` Jiri Olsa
2020-11-09 21:53 ` [PATCH 04/24] tools headers uapi: Sync tools/include/uapi/linux/perf_event.h Jiri Olsa
2020-11-09 21:53 ` [PATCH 05/24] perf tools: Do not swap mmap2 fields in case it contains build id Jiri Olsa
2020-11-09 21:53 ` [PATCH 06/24] perf tools: Add build_id__is_defined function Jiri Olsa
2020-11-09 21:53 ` [PATCH 07/24] perf tools: Add filename__decompress function Jiri Olsa
2020-11-09 21:53 ` [PATCH 08/24] perf tools: Add support to read build id from compressed elf Jiri Olsa
2020-11-09 21:54 ` [PATCH 09/24] perf tools: Add check for existing link in buildid dir Jiri Olsa
2020-11-09 21:54 ` [PATCH 10/24] perf tools: Use struct extra_kernel_map in machine__process_kernel_mmap_event Jiri Olsa
2020-11-09 21:54 ` [PATCH 11/24] perf tools: Try to load vmlinux from buildid database Jiri Olsa
2020-11-09 21:54 ` [PATCH 12/24] perf tools: Store build id from mmap2 events Jiri Olsa
2020-11-09 21:54 ` [PATCH 13/24] perf tools: Allow mmap2 event to synthesize kernel image Jiri Olsa
2020-11-09 21:54 ` [PATCH 14/24] perf tools: Allow mmap2 event to synthesize modules Jiri Olsa
2020-11-09 21:54 ` [PATCH 15/24] perf tools: Synthesize build id for kernel/modules/tasks Jiri Olsa
2020-11-13  4:32   ` Namhyung Kim
2020-11-13 11:10     ` Jiri Olsa
2020-11-09 21:54 ` [PATCH 16/24] perf tools: Add support to display build id for mmap2 events Jiri Olsa
2020-11-09 21:54 ` [PATCH 17/24] perf tools: Use machine__for_each_dso in perf_session__cache_build_ids Jiri Olsa
2020-11-09 21:54 ` [PATCH 18/24] perf tools: Add __perf_session__cache_build_ids function Jiri Olsa
2020-11-09 21:54 ` [PATCH 19/24] perf tools: Add is_perf_data function Jiri Olsa
2020-11-09 21:54 ` [PATCH 20/24] perf tools: Add build_id_cache__add function Jiri Olsa
2020-11-09 21:54 ` [PATCH 21/24] perf buildid-cache: Add support to add build ids from perf data Jiri Olsa
2020-11-09 21:54 ` [PATCH 22/24] perf buildid-cache: Add --debuginfod option Jiri Olsa
     [not found]   ` <CAP-5=fUDtTU2XYr6w6wYndP6RVFDLoJSnC31m+djA-r9EVMQiw@mail.gmail.com>
2020-11-23 22:26     ` Jiri Olsa
2020-11-09 21:54 ` [PATCH 23/24] perf buildid-list: Add support for mmap2's buildid events Jiri Olsa
2020-11-09 21:54 ` [PATCH 24/24] perf record: Add --buildid-mmap option to enable mmap's build id Jiri Olsa
2020-11-11 17:00   ` Andi Kleen
2020-11-12 11:57     ` Jiri Olsa
2020-11-12 20:39       ` Arnaldo Carvalho de Melo
2020-11-12 21:25         ` Jiri Olsa
2020-11-13  4:40   ` Namhyung Kim
2020-11-13 11:09     ` Jiri Olsa
2020-11-14  0:31       ` Namhyung Kim
2020-11-14 20:44         ` Jiri Olsa
2020-11-17 11:00 [PATCHv2 00/24] perf: Add mmap2 build id support Jiri Olsa
2020-11-17 11:00 ` [PATCH 03/24] perf: Add build id data in mmap2 event Jiri Olsa
2020-11-17 11:13   ` Peter Zijlstra
2020-11-26 16:55     ` Jiri Olsa

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