From: Jiri Olsa <olsajiri@gmail.com>
To: Song Liu <song@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Hou Tao <houtao1@huawei.com>, Daniel Xu <dxu@dxuuu.xyz>
Subject: Re: [PATCHv2 bpf-next 3/9] bpf: Add missed value to kprobe perf link info
Date: Sun, 10 Sep 2023 20:54:48 +0200 [thread overview]
Message-ID: <ZP4Q+LnN1x8mUDxY@krava> (raw)
In-Reply-To: <CAPhsuW4aiVoGwN7quqCUiXS7HrKtSyPbR4dsgoXw=wcgWuybew@mail.gmail.com>
On Fri, Sep 08, 2023 at 09:49:17AM -0700, Song Liu wrote:
SNIP
> > the bpf link has access to its attach layer, like perf event for kprobe
> > in perf_link or fprobe for kprobe_multi link... so it's convenient to
> > reach out from link for these stats and make them available through
> > bpf_link_info
> >
> > also there's no other way to get these data for some links
> >
> > like we could perhaps add some perf event specific interface to retrieve
> > these stats for kprobes, because we have access to the perf event in user
> > space, but that's not the case for kprobe_multi link, because there's no
> > other way to reach the fprobe object
>
> Fair enough. I guess this is a good stat to have for the bpf link.
>
> More question about kprobe_multi: Shall we (or can we) collect "missed" for each
> individual function we attach to?
I think it's possible, but we'd need to keep/lookup stats for each
function/addr same way we do for cookies ... so it'd mean bsearch
on each missed path.. which might be not that bad, considering it's
error path instead of executing bpf program.. also it can be optional
jirka
next prev parent reply other threads:[~2023-09-10 18:54 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-07 7:13 [PATCHv2 bpf-next 0/9] bpf: Add missed stats for kprobes Jiri Olsa
2023-09-07 7:13 ` [PATCHv2 bpf-next 1/9] bpf: Count stats for kprobe_multi programs Jiri Olsa
2023-09-07 18:09 ` Song Liu
2023-09-07 7:13 ` [PATCHv2 bpf-next 2/9] bpf: Add missed value to kprobe_multi link info Jiri Olsa
2023-09-07 18:15 ` Song Liu
2023-09-07 7:13 ` [PATCHv2 bpf-next 3/9] bpf: Add missed value to kprobe perf " Jiri Olsa
2023-09-07 18:40 ` Song Liu
2023-09-08 11:43 ` Jiri Olsa
2023-09-08 16:49 ` Song Liu
2023-09-10 18:54 ` Jiri Olsa [this message]
2023-09-08 23:22 ` Andrii Nakryiko
2023-09-08 23:32 ` Song Liu
2023-09-08 23:44 ` Andrii Nakryiko
2023-09-10 18:54 ` Jiri Olsa
2023-09-07 7:13 ` [PATCHv2 bpf-next 4/9] bpf: Count missed stats in trace_call_bpf Jiri Olsa
2023-09-07 18:46 ` Song Liu
2023-09-07 7:13 ` [PATCHv2 bpf-next 5/9] bpftool: Display missed count for kprobe_multi link Jiri Olsa
2023-09-07 7:13 ` [PATCHv2 bpf-next 6/9] bpftool: Display missed count for kprobe perf link Jiri Olsa
2023-09-07 7:13 ` [PATCHv2 bpf-next 7/9] selftests/bpf: Add test for missed counts of perf event link kprobe Jiri Olsa
2023-09-07 18:52 ` Song Liu
2023-09-08 23:25 ` Andrii Nakryiko
2023-09-10 18:54 ` Jiri Olsa
2023-09-07 7:13 ` [PATCHv2 bpf-next 8/9] selftests/bpf: Add test for recursion " Jiri Olsa
2023-09-07 18:55 ` Song Liu
2023-09-14 7:56 ` Jiri Olsa
2023-09-07 7:13 ` [PATCHv2 bpf-next 9/9] selftests/bpf: Add test for recursion counts of perf event link tracepoint Jiri Olsa
2023-09-07 19:00 ` Song Liu
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