From: Christoph Hellwig <hch@infradead.org>
To: changfengnan <changfengnan@bytedance.com>
Cc: Joanne Koong <joannelkoong@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
brauner <brauner@kernel.org>, djwong <djwong@kernel.org>,
ojaswin <ojaswin@linux.ibm.com>, dgc <dgc@kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-ext4 <linux-ext4@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
lidiangang@bytedance.com,
"pankaj.raghav" <pankaj.raghav@linux.dev>,
Brian Foster <bfoster@redhat.com>
Subject: Re: [PATCH v6 3/3] iomap: add simple dio path for small direct I/O
Date: Fri, 3 Jul 2026 05:40:21 -0700 [thread overview]
Message-ID: <akettUm5gBD8nj56@infradead.org> (raw)
In-Reply-To: <d9210bcdf73fbe1ac8b6ec132865609a3ed68688.e3ea485f.90a4.4656.9103.275b1cd29206@bytedance.com>
On Fri, Jul 03, 2026 at 05:13:12PM +0800, changfengnan wrote:
> taken, which introduced some overhead.
> I implemented some optimizations based on Christoph’s suggestions and
> made some modifications to `iomap_process`;
> Now, XFS performance is essentially unchanged, while ext4 still shows a
> 1.5% drop; I will continue to investigate the cause.. I’ve attached the patch.
> Actually, I had expected that switching to `iomap_next` would improve
> performance, since it avoids an indirect call.
I don't think it will for you - the direct I/O readers don't have
iomap_end methods, so you still have the same number of indirect
calls. What could help is to inline the iterator as seen in Joannes'
fist demo series. We could even look into doing that only for simple
dio in a first step, shifting the burden to use the simple method
to the callers (at least for the POC).
next prev parent reply other threads:[~2026-07-03 12:40 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-01 3:32 [PATCH v6 0/3] iomap: add simple dio path for small direct I/O Fengnan Chang
2026-07-01 3:32 ` [PATCH v6 1/3] iomap: factor out iomap_dio_alignment helper Fengnan Chang
2026-07-01 3:32 ` [PATCH v6 2/3] iomap: pass error code to should_report_dio_fserror directly Fengnan Chang
2026-07-01 3:32 ` [PATCH v6 3/3] iomap: add simple dio path for small direct I/O Fengnan Chang
2026-07-01 11:23 ` Christoph Hellwig
2026-07-01 19:35 ` Joanne Koong
2026-07-02 14:35 ` Christoph Hellwig
2026-07-03 3:05 ` Joanne Koong
2026-07-03 9:13 ` changfengnan
2026-07-03 12:40 ` Christoph Hellwig [this message]
2026-07-06 11:09 ` changfengnan
2026-07-06 19:27 ` Joanne Koong
2026-07-03 9:22 ` changfengnan
2026-07-01 12:44 ` [PATCH v6 0/3] " Christian Brauner
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