From: Breno Leitao <leitao@debian.org>
To: Mateusz Guzik <mjguzik@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
Josh Triplett <josh@joshtriplett.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Shuah Khan <shuah@kernel.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org, shakeel.butt@linux.dev,
jlayton@kernel.org, axboe@kernel.dk, kernel-team@meta.com
Subject: Re: [PATCH v3 0/2] fs/pipe: reduce pipe->mutex contention by pre-allocating outside the lock
Date: Wed, 17 Jun 2026 10:39:49 -0700 [thread overview]
Message-ID: <ajLWi_3zqo9uqkWc@gmail.com> (raw)
In-Reply-To: <rlios6fzl4xc2p57aurth2bpt2iflskf6crabqi4u45f6mejbm@ekxu5ua6wa5c>
On Wed, Jun 17, 2026 at 05:01:04PM +0200, Mateusz Guzik wrote:
> On Wed, Jun 17, 2026 at 03:23:54AM -0700, Breno Leitao wrote:
> > Measured it to _just be sure_, 1-byte ping-pong (perf bench sched pipe -s 1):
> >
> > baseline: 2.674 usecs/op
> > patched: 2.710 usecs/op (+1.3%, within run-to-run noise)
> >
>
> Can you try this:
I've tested this change, but the results show no real measurable
improvement beyond measurement noise.
patched + your change: ~2.66 usecs/op (-1.7%, within noise)
In my experience, branch hints haven't proven particularly effective, at
least that was the case when I worked on PowerPC some time ago.
prev parent reply other threads:[~2026-06-17 17:40 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-24 14:44 [PATCH v3 0/2] fs/pipe: reduce pipe->mutex contention by pre-allocating outside the lock Breno Leitao
2026-05-24 14:44 ` [PATCH v3 1/2] fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write Breno Leitao
2026-05-24 14:44 ` [PATCH v3 2/2] selftests/pipe: add pipe_bench microbenchmark Breno Leitao
2026-05-28 12:34 ` [PATCH v3 0/2] fs/pipe: reduce pipe->mutex contention by pre-allocating outside the lock Christian Brauner
2026-06-16 20:47 ` Josh Triplett
2026-06-17 8:52 ` Oleg Nesterov
2026-06-17 10:23 ` Breno Leitao
2026-06-17 11:59 ` Mateusz Guzik
2026-06-17 14:37 ` Oleg Nesterov
2026-06-17 14:47 ` Breno Leitao
2026-06-17 14:57 ` Mateusz Guzik
2026-06-17 15:26 ` Breno Leitao
2026-06-17 15:45 ` Oleg Nesterov
2026-06-17 14:51 ` Mateusz Guzik
2026-06-17 15:30 ` Oleg Nesterov
2026-06-17 16:04 ` Oleg Nesterov
2026-06-17 15:01 ` Mateusz Guzik
2026-06-17 17:39 ` Breno Leitao [this message]
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