Re: [PATCHv4 bpf-next 0/7] uprobe: uretprobe speed up

[Jiri Olsa <olsajiri@gmail.com>]

On Fri, May 03, 2024 at 11:03:24AM -0700, Andrii Nakryiko wrote:
> On Thu, May 2, 2024 at 1:04 PM Jiri Olsa <olsajiri@gmail.com> wrote:
> >
> > On Thu, May 02, 2024 at 09:43:02AM -0700, Andrii Nakryiko wrote:
> > > On Thu, May 2, 2024 at 5:23 AM Jiri Olsa <jolsa@kernel.org> wrote:
> > > >
> > > > hi,
> > > > as part of the effort on speeding up the uprobes [0] coming with
> > > > return uprobe optimization by using syscall instead of the trap
> > > > on the uretprobe trampoline.
> > > >
> > > > The speed up depends on instruction type that uprobe is installed
> > > > and depends on specific HW type, please check patch 1 for details.
> > > >
> > > > Patches 1-6 are based on bpf-next/master, but path 1 and 2 are
> > > > apply-able on linux-trace.git tree probes/for-next branch.
> > > > Patch 7 is based on man-pages master.
> > > >
> > > > v4 changes:
> > > >   - added acks [Oleg,Andrii,Masami]
> > > >   - reworded the man page and adding more info to NOTE section [Masami]
> > > >   - rewrote bpf tests not to use trace_pipe [Andrii]
> > > >   - cc-ed linux-man list
> > > >
> > > > Also available at:
> > > >   https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
> > > >   uretprobe_syscall
> > > >
> > >
> > > It looks great to me, thanks! Unfortunately BPF CI build is broken,
> > > probably due to some of the Makefile additions, please investigate and
> > > fix (or we'll need to fix something on BPF CI side), but it looks like
> > > you'll need another revision, unfortunately.
> > >
> > > pw-bot: cr
> > >
> > >   [0] https://github.com/kernel-patches/bpf/actions/runs/8923849088/job/24509002194
> >
> > yes, I think it's missing the 32-bit libc for uprobe_compat binary,
> > probably it needs to be added to github.com:libbpf/ci.git setup-build-env/action.yml ?
> > hm but I'm not sure how to test it, need to check
> 
> You can create a custom PR directly against Github repo
> (kernel-patches/bpf) and BPF CI will run all the tests on your custom
> code. This way you can iterate without spamming the mailing list.

I'm running CI tests like that, but I think I need to change the action
which is in other repo (github.com:libbpf/ci.git)

> 
> But I'm just wondering if it's worth complicating setup just for
> testing this x32 compat mode. So maybe just dropping one of those
> patches would be better?

well, we had compat process crashing on uretprobe because of this change,
so I rather keep the test.. or it can go in later on when the CI stuff is
figured out.. I got busy with the shadow stack issue today, will check on
the CI PR next week

jirka