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Date:   Wed, 7 Nov 2018 09:40:57 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Song Liu <songliubraving@fb.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@fb.com, ast@kernel.org, daniel@iogearbox.net,
        acme@kernel.org
Subject: Re: [RFC perf,bpf 1/5] perf, bpf: Introduce PERF_RECORD_BPF_EVENT
Message-ID: <20181107084057.GG9781@hirez.programming.kicks-ass.net>
References: <20181106205246.567448-1-songliubraving@fb.com>
 <20181106205246.567448-2-songliubraving@fb.com>
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On Tue, Nov 06, 2018 at 12:52:42PM -0800, Song Liu wrote:
> For better performance analysis of BPF programs, this patch introduces
> PERF_RECORD_BPF_EVENT, a new perf_event_type that exposes BPF program
> load/unload information to user space.
> 
>         /*
>          * Record different types of bpf events:
>          *   enum perf_bpf_event_type {
>          *      PERF_BPF_EVENT_UNKNOWN          = 0,
>          *      PERF_BPF_EVENT_PROG_LOAD        = 1,
>          *      PERF_BPF_EVENT_PROG_UNLOAD      = 2,
>          *   };
>          *
>          * struct {
>          *      struct perf_event_header header;
>          *      u16 type;
>          *      u16 flags;
>          *      u32 id;  // prog_id or map_id
>          * };
>          */
>         PERF_RECORD_BPF_EVENT                   = 17,
> 
> PERF_RECORD_BPF_EVENT contains minimal information about the BPF program.
> Perf utility (or other user space tools) should listen to this event and
> fetch more details about the event via BPF syscalls
> (BPF_PROG_GET_FD_BY_ID, BPF_OBJ_GET_INFO_BY_FD, etc.).

Why !? You're failing to explain why it cannot provide the full
information there.