Re: [PATCH v1] samples/bpf: Add a trace tool with perf PMU counters
From: Leo Yan
Date: Mon Jan 20 2025 - 16:37:32 EST
On Mon, Jan 20, 2025 at 08:54:30PM +0100, Daniel Borkmann wrote:
> On 1/20/25 8:38 PM, Alexei Starovoitov wrote:
> > On Mon, Jan 20, 2025 at 10:50 AM Leo Yan <leo.yan@xxxxxxx> wrote:
[...]
> > > My understanding for bpftool is for eBPF program specific. I looked
> > > into a bit the commit 47c09d6a9f67, it is nature for integrating the
> > > tracing feature for eBPF program specific. My patch is for tracing
> > > normal userspace programs, I am not sure if this is really wanted by
> > > bpftool. I would like to hear opinions from bpftool maintainer before
> > > proceeding.
>
> Yes, that suggestion was if it would have been applicable also
> for the existing bpftool (BPF program) profiling functionality.
>
> > > My program mainly uses eBPF attaching to uprobe. selftest/bpf has
> > > contained the related functionality testing, actually I refered the
> > > test for writing my code :). So maybe it is not quite useful for
> > > merging the code as a test?
> > >
> > > If both options are not ideal, I would spend time to land the
> > > feature in perf tool - the perf tool has supported eBPF backend for
> > > reading PMU counters, but it is absent function based profiling.
> >
> > We don't add tools to kernel repo. bpftool is an exception
> > because it's used during the selftest build.
> > 'perf' is another exception for historical reasons.
> >
> > This particular feature fits 'perf' the best.
>
> Agree, looks like perf is the best target for integration then.
Thanks for suggestions, Alexei and Daniel. It makes sense for me to
move to perf, and now I understand the policy for moving code from
samples/bpf.
It may be irrelevant to the patch itself. I know we have great BPF
toolings (BCC/bpftrace, etc), but it would be a bit confused for me
that we don't have a offical repo to maintain C based BPF toolkits.
Sometimes, C based BPF tool is small and handy ...
Thanks,
Leo