Re: [PATCH 00/10] perf/uprobe: Optimize uprobes

From: Jiri Olsa
Date: Tue Jul 09 2024 - 06:01:27 EST


On Tue, Jul 09, 2024 at 11:03:04AM +0200, Peter Zijlstra wrote:
> On Mon, Jul 08, 2024 at 05:25:14PM -0700, Andrii Nakryiko wrote:
>
> > Ramping this up to 16 threads shows that mmap_rwsem is getting more
> > costly, up to 45% of CPU. SRCU is also growing a bit slower to 19% of
> > CPU. Is this expected? (I'm not familiar with the implementation
> > details)
>
> SRCU getting more expensive is a bit unexpected, it's just a per-cpu
> inc/dec and a full barrier.
>
> > P.S. Would you be able to rebase your patches on top of latest
> > probes/for-next, which include Jiri's sys_uretprobe changes. Right now
> > uretprobe benchmarks are quite unrepresentative because of that.
>
> What branch is that? kernel/events/ stuff usually goes through tip, no?

it went through the trace tree:

https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git probes/for-next

and it's in linux-next/master already

jirka