From: "hch@lst.de" <hch@lst.de>
To: Michael Kelley <mhklinux@outlook.com>
Cc: "axboe@kernel.dk" <axboe@kernel.dk>, "hch@lst.de" <hch@lst.de>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>
Subject: Re: Merging raw block device writes
Date: Mon, 27 Nov 2023 07:59:28 +0100 [thread overview]
Message-ID: <20231127065928.GA27811@lst.de> (raw)
In-Reply-To: <SN6PR02MB41575884C4898B59615B496AD4BFA@SN6PR02MB4157.namprd02.prod.outlook.com>
On Sat, Nov 25, 2023 at 05:38:28PM +0000, Michael Kelley wrote:
> Hyper-V guests and the Azure cloud have a particular interest here
> because Hyper-V guests uses SCSI as the standard interface to virtual
> disks. Azure cloud disks can be throttled to a limited number of IOPS,
> so the number of in-flights I/Os can be relatively high, and
> merging can be beneficial to staying within the throttle
> limits. Of the flip side, this problem hasn't generated complaints
> over the last 18 months that I'm aware of, though that may be more
> because commercial distros haven't been running 5.16 or later kernels
> until relatively recently.
I think the more important thing is that if you care about reducing
the number of I/Os you probably should use an I/O scheduler. Reducing
the number of I/Os without an I/O scheduler isn't (and I'll argue
shouldn't) be a concern for the non I/O scheduler.
next prev parent reply other threads:[~2023-11-27 6:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-25 17:38 Merging raw block device writes Michael Kelley
2023-11-27 6:59 ` hch [this message]
2023-11-27 16:10 ` Jens Axboe
2023-11-28 19:29 ` Michael Kelley
2023-11-28 21:59 ` Jens Axboe
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