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Date:   Mon, 19 Dec 2022 10:24:07 -0800
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Subject: Re: [bpf-next v2 1/2] bpf: add runtime stats, max cost
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To:     Tonghao Zhang <xiangxia.m.yue@gmail.com>
Cc:     Daniel Borkmann <daniel@iogearbox.net>,
        Yonghong Song <yhs@meta.com>, bpf@vger.kernel.org,
        Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        Hou Tao <houtao1@huawei.com>, Song Liu <song@kernel.org>
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On 12/19/22 12:04 AM, Song Liu wrote:
> While max time cost might be useful in some debugging, I don't think
> we should add it with kernel.bpf_stats_enabled. Otherwise, we can
> argue p50/p90/p99 are also useful in some cases, and some other
> metrics are useful in some other cases.  These metrics together will
> make kernel.bpf_stats_enabled too expensive for the use case above.
> 
> Since the use case is for debugging, have you considered using
> some other BPF programs to profile the target BPF program?
> Please refer to "bpftool prog profile" or "perf stat -b " for
> examples of similar solutions.
+1.  Please consider other suggested solutions that the same can be done in a 
more flexible way.