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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240709090304.GG27299@noisy.programming.kicks-ass.net>
Date: Tue, 9 Jul 2024 11:03:04 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Andrii Nakryiko <andrii.nakryiko@...il.com>
Cc: Masami Hiramatsu <mhiramat@...nel.org>, mingo@...nel.org,
	andrii@...nel.org, linux-kernel@...r.kernel.org,
	rostedt@...dmis.org, oleg@...hat.com, jolsa@...nel.org,
	clm@...a.com, paulmck@...nel.org, bpf <bpf@...r.kernel.org>
Subject: Re: [PATCH 00/10] perf/uprobe: Optimize uprobes

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?