From: Jens Axboe <axboe@kernel.dk>
To: Breno Leitao <leitao@debian.org>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
tj@kernel.org, josef@toxicpanda.com, kernel-team@meta.com
Subject: Re: [PATCH] blk-rq-qos: Remove unlikely() hints from QoS checks
Date: Tue, 06 Jan 2026 19:10:47 -0700 [thread overview]
Message-ID: <176775184768.14145.3891847681300037489.b4-ty@kernel.dk> (raw)
In-Reply-To: <20260106-blk_unlikely-v1-1-90fb556a6776@debian.org>
On Tue, 06 Jan 2026 06:26:57 -0800, Breno Leitao wrote:
> The unlikely() annotations on QUEUE_FLAG_QOS_ENABLED checks are
> counterproductive. Writeback throttling (WBT) might be enabled by
> default, mainly because CONFIG_BLK_WBT_MQ defaults to 'y'.
>
> Branch profiling on Meta servers, which have WBT enabled, confirms 100%
> misprediction rates on these checks.
>
> [...]
Applied, thanks!
[1/1] blk-rq-qos: Remove unlikely() hints from QoS checks
commit: 7d121d701d58a92f26decb10da1d04a88b74519d
Best regards,
--
Jens Axboe
prev parent reply other threads:[~2026-01-07 2:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-06 14:26 Breno Leitao
2026-01-07 2:10 ` Jens Axboe [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=176775184768.14145.3891847681300037489.b4-ty@kernel.dk \
--to=axboe@kernel.dk \
--cc=josef@toxicpanda.com \
--cc=kernel-team@meta.com \
--cc=leitao@debian.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®