netdev - Re: [RFC perf,bpf 1/5] perf, bpf: Introduce PERF_RECORD_BPF

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Date:   Thu, 8 Nov 2018 11:26:12 -0700
From:   David Ahern <dsahern@...il.com>
To:     Song Liu <songliubraving@...com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Netdev <netdev@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Kernel Team <Kernel-team@...com>,
        "ast@...nel.org" <ast@...nel.org>,
        "daniel@...earbox.net" <daniel@...earbox.net>,
        "acme@...nel.org" <acme@...nel.org>
Subject: Re: [RFC perf,bpf 1/5] perf, bpf: Introduce PERF_RECORD_BPF_EVENT

On 11/8/18 11:04 AM, Song Liu wrote:
> On the other hand, processing BPF load/unload events synchronously should
> not introduce too much overhead for meaningful use cases. If many BPF progs
> are being loaded/unloaded within short period of time, it is not the steady
> state that profiling works care about. 

but, profiling is not the only use case, and perf-record is common with
those other use cases.

I think that answers why your RFC set does not fork a thread for the bpf
events. You are focused on profiling and for already loaded programs or
for a small number of programs loaded by a specific workload started by
perf.