From: Jens Axboe <[email protected]>
To: Pavel Begunkov <[email protected]>
Cc: Alexander Viro <[email protected]>,
[email protected], [email protected],
[email protected], [email protected],
Christoph Hellwig <[email protected]>,
Matthew Wilcox <[email protected]>,
Ming Lei <[email protected]>,
Johannes Weiner <[email protected]>
Subject: Re: [RFC 0/2] nocopy bvec for direct IO
Date: Wed, 9 Dec 2020 09:53:49 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 12/8/20 7:19 PM, Pavel Begunkov wrote:
> The idea is to avoid copying, merging, etc. bvec from iterator to bio
> in direct I/O and use the one we've already got. Hook it up for io_uring.
> Had an eye on it for a long, and it also was brought up by Matthew
> just recently. Let me know if I forgot or misplaced some tags.
>
> A benchmark got me 430KIOPS vs 540KIOPS, or +25% on bare metal. And perf
> shows that bio_iov_iter_get_pages() was taking ~20%. The test is pretty
> silly, but still imposing. I'll redo it closer to reality for next
> iteration, anyway need to double check some cases.
>
> If same applied to iomap, common chunck can be moved from block_dev
> into bio_iov_iter_get_pages(), but if there any benefit for filesystems,
> they should explicitly opt in with ITER_BVEC_FLAG_FIXED.
Ran this on a real device, and I get a 10% bump in performance with it.
That's pretty amazing! So please do pursue this one and pull it to
completion.
--
Jens Axboe
next prev parent reply other threads:[~2020-12-09 16:55 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 2:19 [RFC 0/2] nocopy bvec for direct IO Pavel Begunkov
2020-12-09 2:19 ` [PATCH 1/2] iov: introduce ITER_BVEC_FLAG_FIXED Pavel Begunkov
2020-12-09 8:36 ` Christoph Hellwig
2020-12-09 9:06 ` Christoph Hellwig
2020-12-09 11:54 ` Pavel Begunkov
2020-12-09 13:07 ` Al Viro
2020-12-09 13:37 ` Pavel Begunkov
2020-12-09 17:55 ` Christoph Hellwig
2020-12-09 18:24 ` Matthew Wilcox
2020-12-13 22:09 ` Pavel Begunkov
2020-12-09 2:19 ` [PATCH 2/2] block: no-copy bvec for direct IO Pavel Begunkov
2020-12-09 8:40 ` Christoph Hellwig
2020-12-09 12:01 ` Pavel Begunkov
2020-12-09 12:05 ` Christoph Hellwig
2020-12-09 12:03 ` Pavel Begunkov
2020-12-11 14:06 ` Johannes Weiner
2020-12-11 14:20 ` Pavel Begunkov
2020-12-11 15:38 ` Johannes Weiner
2020-12-11 15:47 ` Pavel Begunkov
2020-12-11 16:13 ` Johannes Weiner
2020-12-09 21:13 ` David Laight
2020-12-09 6:50 ` [RFC 0/2] nocopy " Christoph Hellwig
2020-12-09 11:54 ` Pavel Begunkov
2020-12-09 16:53 ` Jens Axboe [this message]
2020-12-13 22:03 ` Pavel Begunkov
2020-12-09 17:06 ` Al Viro
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