From: Matthew Wilcox <willy@infradead.org>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@kernel.org>, Luis Chamberlain <mcgrof@kernel.org>,
lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org,
linux-mm <linux-mm@kvack.org>,
Daniel Gomez <da.gomez@samsung.com>,
Pankaj Raghav <p.raghav@samsung.com>,
Jens Axboe <axboe@kernel.dk>, Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@lst.de>, Chris Mason <clm@fb.com>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [LSF/MM/BPF TOPIC] Measuring limits and enhancing buffered IO
Date: Tue, 27 Feb 2024 15:39:35 +0000 [thread overview]
Message-ID: <Zd4CN3x2RzSfKEtm@casper.infradead.org> (raw)
In-Reply-To: <yfzkhghkh36ww5nzmkdrdpcjy6w5v6us55ccmnh2phjla25mmz@xomuheona22l>
On Tue, Feb 27, 2024 at 02:21:59AM -0500, Kent Overstreet wrote:
> On Mon, Feb 26, 2024 at 03:48:35PM -0800, Linus Torvalds wrote:
> > On Mon, 26 Feb 2024 at 14:46, Linus Torvalds
> > <torvalds@linux-foundation.org> wrote:
> > >
> > > I really haven't tested this AT ALL. I'm much too scared.
> >
> > "Courage is not the absence of fear, but acting in spite of it"
> > - Paddington Bear / Michal Scott
> >
> > It seems to actually boot here.
> >
> > That said, from a quick test with lots of threads all hammering on the
> > same page - I'm still not entirely convinced it makes a difference.
> > Sure, the kernel profile changes, but filemap_get_read_batch() wasn't
> > very high up in the profile to begin with.
> >
> > I didn't do any actual performance testing, I just did a 64-byte pread
> > at offset 0 in a loop in 64 threads on my 32c/64t machine.
>
> Only rough testing, but this is looking like around a 25% performance
> increase doing 4k random reads on a 1G file with fio, 8 jobs, on my
> Ryzen 5950x - 16.7M -> 21.4M iops, very roughly. fio's a pig and we're
> only spending half our cpu time in the kernel, so the buffered read path
> is actually getting 40% or 50% faster.
Linus' patch only kicks in for 128 bytes or smaller. So what are you
measuring?
next prev parent reply other threads:[~2024-02-27 15:39 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-23 23:59 [LSF/MM/BPF TOPIC] Measuring limits and enhancing buffered IO Luis Chamberlain
2024-02-24 4:12 ` Matthew Wilcox
2024-02-24 17:31 ` Linus Torvalds
2024-02-24 18:13 ` Matthew Wilcox
2024-02-24 18:24 ` Linus Torvalds
2024-02-24 18:20 ` Linus Torvalds
2024-02-24 19:11 ` Linus Torvalds
2024-02-24 21:42 ` Theodore Ts'o
2024-02-24 22:57 ` Chris Mason
2024-02-24 23:40 ` Linus Torvalds
2024-05-10 23:57 ` Luis Chamberlain
2024-02-25 5:18 ` Kent Overstreet
2024-02-25 6:04 ` Kent Overstreet
2024-02-25 13:10 ` Matthew Wilcox
2024-02-25 17:03 ` Linus Torvalds
2024-02-25 21:14 ` Matthew Wilcox
2024-02-25 23:45 ` Linus Torvalds
2024-02-26 1:02 ` Kent Overstreet
2024-02-26 1:32 ` Linus Torvalds
2024-02-26 1:58 ` Kent Overstreet
2024-02-26 2:06 ` Kent Overstreet
2024-02-26 2:34 ` Linus Torvalds
2024-02-26 2:50 ` Al Viro
2024-02-26 17:17 ` Linus Torvalds
2024-02-26 21:07 ` Matthew Wilcox
2024-02-26 21:17 ` Kent Overstreet
2024-02-26 21:19 ` Kent Overstreet
2024-02-26 21:55 ` Paul E. McKenney
2024-02-26 23:29 ` Kent Overstreet
2024-02-27 0:05 ` Paul E. McKenney
2024-02-27 0:29 ` Kent Overstreet
2024-02-27 0:55 ` Paul E. McKenney
2024-02-27 1:08 ` Kent Overstreet
2024-02-27 5:17 ` Paul E. McKenney
2024-02-27 6:21 ` Kent Overstreet
2024-02-27 15:32 ` Paul E. McKenney
2024-02-27 15:52 ` Kent Overstreet
2024-02-27 16:06 ` Paul E. McKenney
2024-02-27 15:54 ` Matthew Wilcox
2024-02-27 16:21 ` Paul E. McKenney
2024-02-27 16:34 ` Kent Overstreet
2024-02-27 17:58 ` Paul E. McKenney
2024-02-28 23:55 ` Kent Overstreet
2024-02-29 19:42 ` Paul E. McKenney
2024-02-29 20:51 ` Kent Overstreet
2024-03-05 2:19 ` Paul E. McKenney
2024-02-27 0:43 ` Dave Chinner
2024-02-26 22:46 ` Linus Torvalds
2024-02-26 23:48 ` Linus Torvalds
2024-02-27 7:21 ` Kent Overstreet
2024-02-27 15:39 ` Matthew Wilcox [this message]
2024-02-27 15:54 ` Kent Overstreet
2024-02-27 16:34 ` Linus Torvalds
2024-02-27 16:47 ` Kent Overstreet
2024-02-27 17:07 ` Linus Torvalds
2024-02-27 17:20 ` Kent Overstreet
2024-02-27 18:02 ` Linus Torvalds
2024-05-14 11:52 ` Luis Chamberlain
2024-05-14 16:04 ` Linus Torvalds
2024-02-25 21:29 ` Kent Overstreet
2024-02-25 17:32 ` Kent Overstreet
2024-02-24 17:55 ` Luis Chamberlain
2024-02-25 5:24 ` Kent Overstreet
2024-02-26 12:22 ` Dave Chinner
2024-02-27 10:07 ` Kent Overstreet
2024-02-27 14:08 ` Luis Chamberlain
2024-02-27 14:57 ` Kent Overstreet
2024-02-27 22:13 ` Dave Chinner
2024-02-27 22:21 ` Kent Overstreet
2024-02-27 22:42 ` Dave Chinner
2024-02-28 7:48 ` [Lsf-pc] " Amir Goldstein
2024-02-28 14:01 ` Chris Mason
2024-02-29 0:25 ` Dave Chinner
2024-02-29 0:57 ` Kent Overstreet
2024-03-04 0:46 ` Dave Chinner
2024-02-27 22:46 ` Linus Torvalds
2024-02-27 23:00 ` Linus Torvalds
2024-02-28 2:22 ` Kent Overstreet
2024-02-28 3:00 ` Matthew Wilcox
2024-02-28 4:22 ` Matthew Wilcox
2024-02-28 17:34 ` Kent Overstreet
2024-02-28 18:04 ` Matthew Wilcox
2024-02-28 18:18 ` Kent Overstreet
2024-02-28 19:09 ` Linus Torvalds
2024-02-28 19:29 ` Kent Overstreet
2024-02-28 20:17 ` Linus Torvalds
2024-02-28 23:21 ` Kent Overstreet
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