From: Christoph Hellwig <hch@infradead.org>
To: "zhaoyang.huang" <zhaoyang.huang@unisoc.com>
Cc: Jens Axboe <axboe@kernel.dk>, Ming Lei <ming.lei@redhat.com>,
linux-mm@kvack.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org,
Zhaoyang Huang <huangzhaoyang@gmail.com>,
steve.kang@unisoc.com
Subject: Re: [RFC PATCH] driver: loop: introduce synchronized read for loop driver
Date: Mon, 22 Sep 2025 11:09:47 -0700 [thread overview]
Message-ID: <aNGQ66CD9F82BFP-@infradead.org> (raw)
In-Reply-To: <20250922032915.3924368-1-zhaoyang.huang@unisoc.com>
On Mon, Sep 22, 2025 at 11:29:15AM +0800, zhaoyang.huang wrote:
> From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
>
> For now, my android system with per pid memcgv2 setup are suffering
> high block_rq_issue to block_rq_complete latency which is actually
> introduced by schedule latency of too many kworker threads. By further
> investigation, we found that the EAS scheduler which will pack small
> load tasks into one CPU core will make this scenario worse. This commit
> would like to introduce a way of synchronized read to be helpful on
> this scenario. The I2C of loop device's request reduced from 14ms to
> 2.1ms under fio test.
So fix the scheduler, or create less helper threads, but this work
around really look like fixing the symptoms instead of even trying
to aim for the root cause.
next prev parent reply other threads:[~2025-09-22 18:09 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-22 3:29 zhaoyang.huang
2025-09-22 18:09 ` Christoph Hellwig [this message]
2025-09-23 3:50 ` Zhaoyang Huang
2025-09-23 16:30 ` Bart Van Assche
2025-09-24 9:13 ` Zhaoyang Huang
2025-09-24 10:04 ` Ming Lei
2025-09-25 1:14 ` Zhaoyang Huang
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