From: Jens Axboe <axboe@kernel.dk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-block <linux-block@vger.kernel.org>,
Matthew Wilcox <willy@infradead.org>, Chris Mason <clm@fb.com>,
Dave Chinner <david@fromorbit.com>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCHSET v3 0/5] Support for RWF_UNCACHED
Date: Wed, 11 Dec 2019 18:11:13 -0700 [thread overview]
Message-ID: <1c93194a-ed91-c3aa-deb5-a3394805defb@kernel.dk> (raw)
In-Reply-To: <CAHk-=wg=hHUFg3i0vDmKEg8HFbEKquAsoC8CJoZpP-8_A1jZDA@mail.gmail.com>
On 12/11/19 6:08 PM, Linus Torvalds wrote:
> On Wed, Dec 11, 2019 at 3:41 PM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> Here's what I did to reproduce:
>
> Gaah. I have a fairly fast ssd (but it's "consumer fast" - Samsung 970
> Pro - I'm assuming yours is a different class), but I encrypt my disk,
> so I only get about 15k iops and I see kcyrptd in my profiles, not
> kswapd.
>
> I didn't even try to worry about RWF_UNCACHED or RWF_NOACCESS, since I
> wanted to see the problem. But I think that with my setup, I can't
> really see it just due to my IO being slow ;(
>
> I do see xas_create and kswapd0, but it's 0.42%. I'm assuming it's the
> very first signs of this problem, but it's certainly not all that
> noticeable.
15K is likely too slow to really show an issue, I'm afraid. The 970
is no slouch, but your crypt setup will likely hamper it a lot. You
don't have a non-encrypted partition on it? I always set aside a
decently sized empty partition on my laptop to be able to run these
kinds of things without having to resort to a test box.
Latency is where it's down the most, you'll likely do better with
more threads to get the IOPS up.
--
Jens Axboe
next prev parent reply other threads:[~2019-12-12 1:11 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-11 15:29 [PATCHSET v3 0/5] Support for RWF_UNCACHED Jens Axboe
2019-12-11 15:29 ` [PATCH 1/5] fs: add read support " Jens Axboe
2019-12-11 15:29 ` [PATCH 2/5] mm: make generic_perform_write() take a struct kiocb Jens Axboe
2019-12-11 15:29 ` [PATCH 3/5] mm: make buffered writes work with RWF_UNCACHED Jens Axboe
2019-12-11 15:29 ` [PATCH 4/5] iomap: pass in the write_begin/write_end flags to iomap_actor Jens Axboe
2019-12-11 17:19 ` Linus Torvalds
2019-12-11 17:19 ` Linus Torvalds
2019-12-11 15:29 ` [PATCH 5/5] iomap: support RWF_UNCACHED for buffered writes Jens Axboe
2019-12-11 17:19 ` Matthew Wilcox
2019-12-11 18:05 ` Jens Axboe
2019-12-12 22:34 ` Dave Chinner
2019-12-13 0:54 ` Jens Axboe
2019-12-13 0:57 ` Jens Axboe
2019-12-16 4:17 ` Dave Chinner
2019-12-17 14:31 ` Jens Axboe
2019-12-18 0:49 ` Dave Chinner
2019-12-18 1:01 ` Jens Axboe
2019-12-11 17:37 ` [PATCHSET v3 0/5] Support for RWF_UNCACHED Linus Torvalds
2019-12-11 17:37 ` Linus Torvalds
2019-12-11 17:56 ` Jens Axboe
2019-12-11 19:14 ` Linus Torvalds
2019-12-11 19:14 ` Linus Torvalds
2019-12-11 19:34 ` Jens Axboe
2019-12-11 20:03 ` Linus Torvalds
2019-12-11 20:03 ` Linus Torvalds
2019-12-11 20:08 ` Jens Axboe
2019-12-11 20:18 ` Linus Torvalds
2019-12-11 20:18 ` Linus Torvalds
2019-12-11 21:04 ` Johannes Weiner
2019-12-12 1:30 ` Jens Axboe
2019-12-11 23:41 ` Jens Axboe
2019-12-12 1:08 ` Linus Torvalds
2019-12-12 1:08 ` Linus Torvalds
2019-12-12 1:11 ` Jens Axboe [this message]
2019-12-12 1:22 ` Linus Torvalds
2019-12-12 1:22 ` Linus Torvalds
2019-12-12 1:29 ` Jens Axboe
2019-12-12 1:41 ` Linus Torvalds
2019-12-12 1:41 ` Linus Torvalds
2019-12-12 1:56 ` Matthew Wilcox
2019-12-12 2:47 ` Linus Torvalds
2019-12-12 2:47 ` Linus Torvalds
2019-12-12 17:52 ` Matthew Wilcox
2019-12-12 18:29 ` Linus Torvalds
2019-12-12 18:29 ` Linus Torvalds
2019-12-12 20:05 ` Matthew Wilcox
2019-12-12 1:41 ` Jens Axboe
2019-12-12 1:49 ` Linus Torvalds
2019-12-12 1:49 ` Linus Torvalds
2019-12-12 1:09 ` Jens Axboe
2019-12-12 2:03 ` Jens Axboe
2019-12-12 2:10 ` Jens Axboe
2019-12-12 2:21 ` Matthew Wilcox
2019-12-12 2:38 ` Jens Axboe
2019-12-12 22:18 ` Dave Chinner
2019-12-13 1:32 ` Chris Mason
2020-01-07 17:42 ` Christoph Hellwig
2020-01-08 14:09 ` Chris Mason
2020-02-01 10:33 ` Andres Freund
2019-12-11 20:43 ` Matthew Wilcox
2019-12-11 20:04 ` Jens Axboe
2019-12-12 10:44 ` Martin Steigerwald
2019-12-12 15:16 ` Jens Axboe
2019-12-12 21:45 ` Martin Steigerwald
2019-12-12 22:15 ` Jens Axboe
2019-12-12 22:18 ` Linus Torvalds
2019-12-12 22:18 ` Linus Torvalds
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