From: Christoph Hellwig <hch@infradead.org>
To: Song Liu <song@kernel.org>
Cc: Guoqing Jiang <jgq516@gmail.com>,
Artur Paszkiewicz <artur.paszkiewicz@intel.com>,
Christoph Hellwig <hch@infradead.org>,
linux-raid <linux-raid@vger.kernel.org>,
linux-block@vger.kernel.org,
Pawe?? Wiejacha <pawel.wiejacha@rtbhouse.com>
Subject: Re: [PATCH] md: don't account io stat for split bio
Date: Tue, 11 May 2021 08:10:16 +0100 [thread overview]
Message-ID: <YJot2JAZkQi7RPGS@infradead.org> (raw)
In-Reply-To: <CAPhsuW44cc2p+29_rLqrq7i3R0d03sjtwRQtbLRkta+jzsdYsw@mail.gmail.com>
On Mon, May 10, 2021 at 11:58:32PM -0700, Song Liu wrote:
> IIUC, the sysfs node is needed to get better performance (by disabling
> accounting)?
FYI, we already have that sysfs file in the block layer
("queue/iostats"), please just observe QUEUE_FLAG_IO_STAT flag.
> in md.c). This
> should simplify the code. If the user do not need extreme performance, we should
> keep the stats on (default). If the user do need extreme performance, s/he could
> disable stats via sysfs.
Given that the code already does a memory allocation it might as well
always clone and do away with the separate md_io allocation entirely.
Memory usage grows a bit, but it can reuse all the bio cloning
infrastructure.
next prev parent reply other threads:[~2021-05-11 7:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-08 3:48 [PATCH] md: don't account io stat for split bio Guoqing Jiang
2021-05-10 6:00 ` Christoph Hellwig
2021-05-10 7:46 ` Guoqing Jiang
2021-05-10 19:49 ` Artur Paszkiewicz
2021-05-11 2:13 ` Guoqing Jiang
2021-05-11 4:38 ` Christoph Hellwig
2021-05-11 6:59 ` Song Liu
2021-05-11 7:11 ` Christoph Hellwig
2021-05-11 6:58 ` Song Liu
2021-05-11 7:10 ` Christoph Hellwig [this message]
2021-05-13 7:24 ` Guoqing Jiang
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