netdev - Re: [PATCH perf,bpf 5/5] perf util: generate bpf_prog_info

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Message-ID: <67063BF9-6237-4CF4-A0EB-0B14C5CA8A21@fb.com>
Date:   Wed, 21 Nov 2018 22:35:35 +0000
From:   Song Liu <songliubraving@...com>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "ast@...nel.org" <ast@...nel.org>,
        "daniel@...earbox.net" <daniel@...earbox.net>,
        "acme@...nel.org" <acme@...nel.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        Kernel Team <Kernel-team@...com>
Subject: Re: [PATCH perf,bpf 5/5] perf util: generate bpf_prog_info_event for
 short living bpf programs



> On Nov 21, 2018, at 2:11 PM, Alexei Starovoitov <alexei.starovoitov@...il.com> wrote:
> 
> On Wed, Nov 21, 2018 at 11:55:02AM -0800, Song Liu wrote:
>> This patch enables perf-record to listen to bpf_event and generate
>> bpf_prog_info_event for bpf programs loaded and unloaded during
>> perf-record run.
>> 
>> To minimize latency between bpf_event and following bpf calls, separate
>> mmap with watermark of 1 is created to process these vip events. Then
>> a separate dummy event is attached to the special mmap. A separate thread
>> is used to only poll bpf events.
>> 
>> By default, perf-record will listen to bpf_event. Option no-bpf-event is
>> added in case the user would opt out.
> 
> I think only default perf-record for sampling should include it.
> perf record -e for tracepoints, kprobes and anything else should imply no-bpf-event.
> 

Maybe something like
  
   if (software_event && ! -g)
        no_bpf_event = true;

?

This will allow attaching kprobe on bpf helper and see which bpf program
calls it. 

Thanks,
Song