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From: Jens Axboe <axboe@kernel.dk>
To: brookxu <brookxu.cn@gmail.com>, tj@kernel.org
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	cgroups@vger.kernel.org
Subject: Re: [PATCH v3] blk-throtl: optimize IOPS throttle for large IO scenarios
Date: Sat, 14 Aug 2021 19:14:37 -0600	[thread overview]
Message-ID: <53196a1f-9fdc-269d-801b-ce1ff2963cb0@kernel.dk> (raw)
In-Reply-To: <65869aaad05475797d63b4c3fed4f529febe3c26.1627876014.git.brookxu@tencent.com>

On 8/1/21 9:51 PM, brookxu wrote:
> From: Chunguang Xu <brookxu@tencent.com>
> 
> After patch 54efd50 (block: make generic_make_request handle
> arbitrarily sized bios), the IO through io-throttle may be larger,
> and these IOs may be further split into more small IOs. However,
> IOPS throttle does not seem to be aware of this change, which
> makes the calculation of IOPS of large IOs incomplete, resulting
> in disk-side IOPS that does not meet expectations. Maybe we should
> fix this problem.
> 
> We can reproduce it by set max_sectors_kb of disk to 128, set
> blkio.write_iops_throttle to 100, run a dd instance inside blkio
> and use iostat to watch IOPS:
> 
> dd if=/dev/zero of=/dev/sdb bs=1M count=1000 oflag=direct
> 
> As a result, without this change the average IOPS is 1995, with
> this change the IOPS is 98.

Applied for 5.15, thanks.

> v3: Optimize the use of atomic variables.
> v2: Use atomic variables to solve synchronization problems.

Just a note for the future, changelog stuff goes below the ---
line.

-- 
Jens Axboe


      parent reply	other threads:[~2021-08-15  1:14 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02  3:51 [PATCH v3] blk-throtl: optimize IOPS throttle for large IO scenarios brookxu
2021-08-09 22:39 ` Tejun Heo
2021-08-14 23:53   ` brookxu.cn
2021-08-15  1:14 ` Jens Axboe [this message]

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