From: Alexey Budankov <alexey.budankov@linux.intel.com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Andi Kleen <ak@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v10 09/12] perf record: implement -z,--compression_level[=<n>] option
Date: Wed, 15 May 2019 18:44:29 +0300 [thread overview]
Message-ID: <175a0cd8-226f-dee4-8919-89f844a6dc8b@linux.intel.com> (raw)
In-Reply-To: <20190515123802.GA23162@kernel.org>
On 15.05.2019 15:59, Arnaldo Carvalho de Melo wrote:
> Em Wed, May 15, 2019 at 11:43:30AM +0300, Alexey Budankov escreveu:
>> On 15.05.2019 0:46, Arnaldo Carvalho de Melo wrote:
>>> Em Tue, May 14, 2019 at 05:20:41PM -0300, Arnaldo Carvalho de Melo escreveu:
>>>> Em Mon, Mar 18, 2019 at 08:44:42PM +0300, Alexey Budankov escreveu:
>
>>>>> Implemented -z,--compression_level[=<n>] option that enables compression
>>>>> of mmaped kernel data buffers content in runtime during perf record
>>>>> mode collection. Default option value is 1 (fastest compression).
>
>>> <SNIP>
>
>>>> [root@quaco ~]# perf record -z2
>>>> ^C[ perf record: Woken up 1 times to write data ]
>>>> 0x1746e0 [0x76]: failed to process type: 81 [Invalid argument]
>>>> [ perf record: Captured and wrote 1.568 MB perf.data, compressed (original 0.452 MB, ratio is 3.995) ]
>
>>>> [root@quaco ~]#
>
>>> So, its the buildid processing at the end, so we can't do build-id
>>> processing when using PERF_RECORD_COMPRESSED, otherwise we'd have to
>>> uncompress at the end to find the PERF_RECORD_FORK/PERF_RECORD_MMAP,
>>> etc.
>
>>> [root@quaco ~]# perf record -z2 --no-buildid sleep 1
>>> [ perf record: Woken up 1 times to write data ]
>>> [ perf record: Captured and wrote 0.020 MB perf.data, compressed (original 0.001 MB, ratio is 2.153) ]
>>> [root@quaco ~]# perf report -D | grep PERF_RECORD_COMP
>>> 0x4f40 [0x195]: failed to process type: 81 [Invalid argument]
>>> Error:
>>> failed to process sample
>>> 0 0x4f40 [0x195]: PERF_RECORD_COMPRESSED
>>> [root@quaco ~]#
>
>>> I'll play with it tomorrow.
>
>> Applied the whole patch set on top of the current perf/core
>> and the whole thing functions as expected.
>
> It doesn't, see the reported error above, these three lines, that
> shouldn't be there:
>
> 0x4f40 [0x195]: failed to process type: 81 [Invalid argument]
> Error:
> failed to process sample
>
> That is because at this point in the patch series a record was
> introduced that is not being handled by the build id processing done, by
> default, at the end of the 'perf record' session, and, as explained
> above, needs fixing so that when we do 'git bisect' looking for a non
> expected "failed to process type: 81" kind of error, this doesn't
> appear.
>
> I added the changes below to this cset and will continue from there:
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index d84a4885e341..f8d21991f94c 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -2284,6 +2284,12 @@ int cmd_record(int argc, const char **argv)
> "cgroup monitoring only available in system-wide mode");
>
> }
> +
> + if (rec->opts.comp_level != 0) {
> + pr_debug("Compression enabled, disabling build id collection at the end of the session\n");
> + rec->no_buildid = true;
> + }
> +
> if (rec->opts.record_switch_events &&
> !perf_can_record_switch_events()) {
> ui__error("kernel does not support recording context switch events\n");
>
> ---------------------------------------------------------------------------
>
> [acme@quaco perf]$ perf record -z2 sleep 1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.001 MB perf.data, compressed (original 0.001 MB, ratio is 2.292) ]
> [acme@quaco perf]$ perf record -v -z2 sleep 1
> Compression enabled, disabling build id collection at the end of the session
> Using CPUID GenuineIntel-6-8E-A
> nr_cblocks: 0
> affinity: SYS
> mmap flush: 1
> comp level: 2
> mmap size 528384B
> Couldn't start the BPF side band thread:
> BPF programs starting from now on won't be annotatable
> perf_event__synthesize_bpf_events: can't get next program: Operation not permitted
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.001 MB perf.data, compressed (original 0.001 MB, ratio is 2.305) ]
> [acme@quaco perf]$
>
> Will check if its possible to get rid of the following in this patch, to
> keep bisection working for this case as well:
>
> [acme@quaco perf]$ perf report -D | grep COMPRESS
> 0x1b8 [0x169]: failed to process type: 81 [Invalid argument]
> Error:
> failed to process sample
> 0 0x1b8 [0x169]: PERF_RECORD_COMPRESSED
> [acme@quaco perf]$
Makes sense. Thanks.
~Alexey
>
> - Arnaldo
>
next prev parent reply other threads:[~2019-05-15 15:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-15 12:59 [PATCH v10 09/12] perf record: implement -z,--compression_level[=<n>] option Arnaldo Carvalho de Melo
2019-05-15 15:44 ` Alexey Budankov [this message]
2019-05-17 15:01 ` Arnaldo Carvalho de Melo
2019-05-17 16:56 ` Alexey Budankov
-- strict thread matches above, loose matches on Subject: below --
2019-03-18 17:36 [PATCH v10 00/12] perf: enable compression of record mode trace to save storage space Alexey Budankov
2019-03-18 17:44 ` [PATCH v10 09/12] perf record: implement -z,--compression_level[=<n>] option Alexey Budankov
2019-05-14 20:04 ` Arnaldo Carvalho de Melo
2019-05-15 5:46 ` Alexey Budankov
2019-05-14 20:20 ` Arnaldo Carvalho de Melo
2019-05-14 21:46 ` Arnaldo Carvalho de Melo
2019-05-15 8:43 ` Alexey Budankov
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