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From: Song Liu <songliubraving@fb.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	"quentin@isovalent.com" <quentin@isovalent.com>,
	Kernel Team <Kernel-team@fb.com>,
	"ast@kernel.org" <ast@kernel.org>,
	"daniel@iogearbox.net" <daniel@iogearbox.net>,
	"arnaldo.melo@gmail.com" <arnaldo.melo@gmail.com>,
	"jolsa@kernel.org" <jolsa@kernel.org>
Subject: Re: [PATCH v4 bpf-next 1/4] bpftool: introduce "prog profile" command
Date: Wed, 4 Mar 2020 21:17:45 +0000	[thread overview]
Message-ID: <D54E47E1-AB6B-46C7-8139-3C43F3E316A8@fb.com> (raw)
In-Reply-To: <20200304192111.GB168640@krava>



> On Mar 4, 2020, at 11:21 AM, Jiri Olsa <jolsa@redhat.com> wrote:
> 
> On Wed, Mar 04, 2020 at 10:07:07AM -0800, Song Liu wrote:
>> With fentry/fexit programs, it is possible to profile BPF program with
>> hardware counters. Introduce bpftool "prog profile", which measures key
>> metrics of a BPF program.
>> 
>> bpftool prog profile command creates per-cpu perf events. Then it attaches
>> fentry/fexit programs to the target BPF program. The fentry program saves
>> perf event value to a map. The fexit program reads the perf event again,
>> and calculates the difference, which is the instructions/cycles used by
>> the target program.
>> 
>> Example input and output:
>> 
>>  ./bpftool prog profile id 337 duration 3 cycles instructions llc_misses
>> 
>>        4228 run_cnt
>>     3403698 cycles                                              (84.08%)
>>     3525294 instructions   #  1.04 insn per cycle               (84.05%)
>>          13 llc_misses     #  3.69 LLC misses per million isns  (83.50%)
> 
> FYI I'm in the middle of moving perf's 'events parsing' interface to libperf,
> which takes event name/s on input and returns list of perf_event_attr objects
> 
>  parse_events("cycles") -> ready to use 'struct perf_event_attr'
> 
> You can use any event that's listed in 'perf list' command, which includes
> also all vendor (Intel/Arm/ppc..) events. It might be useful extension for
> this command.

That's great news! Thanks for the information!

Song


  reply	other threads:[~2020-03-04 21:18 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-04 18:07 [PATCH v4 bpf-next 0/4] bpftool: introduce prog profile Song Liu
2020-03-04 18:07 ` [PATCH v4 bpf-next 1/4] bpftool: introduce "prog profile" command Song Liu
2020-03-04 19:21   ` Jiri Olsa
2020-03-04 21:17     ` Song Liu [this message]
2020-03-04 20:38   ` Jiri Olsa
2020-03-05 20:03     ` Song Liu
2020-03-04 18:07 ` [PATCH v4 bpf-next 2/4] bpftool: Documentation for bpftool prog profile Song Liu
2020-03-04 18:07 ` [PATCH v4 bpf-next 3/4] bpftool: bash completion for "bpftool prog profile" Song Liu
2020-03-04 18:07 ` [PATCH v4 bpf-next 4/4] bpftool: fix typo in bash-completion Song Liu
2020-03-04 19:08 ` [PATCH v4 bpf-next 0/4] bpftool: introduce prog profile Jiri Olsa
2020-03-04 20:41   ` Jiri Olsa
2020-03-04 21:16     ` Song Liu
2020-03-04 21:29       ` Jiri Olsa
2020-03-04 21:39         ` Song Liu
2020-03-05 20:03           ` Song Liu
2020-03-06  8:51             ` Jiri Olsa
2020-03-09 18:04           ` Quentin Monnet
2020-03-09 18:24             ` Song Liu
2020-03-09 19:30               ` Jiri Olsa
2020-03-04 19:13 ` Quentin Monnet

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