From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: ZhangHui <zhanghui31@xiaomi.com>,
bvanassche@acm.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] block: move non sync requests complete flow to softirq
Date: Tue, 3 Sep 2024 21:29:31 -0700 [thread overview]
Message-ID: <ZtfiK1xg2RVzkXW9@infradead.org> (raw)
In-Reply-To: <dd859c1b-40d0-4a10-a6af-0d7fae28da41@kernel.dk>
On Tue, Sep 03, 2024 at 11:49:28AM -0600, Jens Axboe wrote:
> The elephant in the room here is why an 80M completion takes 100 msec?
> That seems... insane.
>
> That aside, doing writes that big isn't great for latencies in general,
> even if they are orders of magnitude smaller (as they should be). Maybe
> this is solvable by just limiting the write size here.
>
> But it really seems out of line for a write that size to take 100 msec
> to process.
pagecache state processing is quite inefficient, we had to limit
the number of them for XFS to avoid latency problems a while ago.
Note that moving to folios means you can process a lot more data
with the same number of completion iterations as well. I'd suggest
the submitter looks into that for whatever file system they are using.
next prev parent reply other threads:[~2024-09-04 4:29 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-03 11:54 [PATCH v3] block: move non sync requests complete flow to softirq ZhangHui
2024-09-03 17:28 ` Bart Van Assche
2024-09-03 17:47 ` Jens Axboe
2024-09-04 3:35 ` [External Mail]Re: " 章辉
2024-09-04 17:22 ` Bart Van Assche
2024-09-05 3:05 ` 章辉
2024-09-03 17:49 ` Jens Axboe
2024-09-04 3:25 ` [External Mail]Re: " 章辉
2024-09-04 4:29 ` Christoph Hellwig [this message]
2024-09-05 2:52 ` 章辉
2024-09-04 8:01 ` Ming Lei
2024-09-05 2:46 ` [External Mail]Re: " 章辉
2024-09-05 3:49 ` Ming Lei
2024-09-05 7:33 ` 章辉
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