All of lore.kernel.org
 help / color / mirror / Atom feed
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 13:04:59 -0700	[thread overview]
Message-ID: <d3ac2d74-f943-9b4c-570c-c7f6e86a475a@kernel.dk> (raw)
In-Reply-To: <e43a2700-8625-e136-dc9d-d0d2da5d96ac@kernel.dk>

On 12/11/19 12:34 PM, Jens Axboe wrote:
> On 12/11/19 10:56 AM, Jens Axboe wrote:
>>> But I think most of the regular IO call chains come through
>>> "mark_page_accessed()". So _that_ is the part you want to avoid (and
>>> maybe the workingset code). And that should be fairly straightforward,
>>> I think.
>>
>> Sure, I can give that a go and see how that behaves.
> 
> Before doing that, I ran a streamed read test instead of just random
> reads, and the behavior is roughly the same. kswapd consumes a bit less
> CPU, but it's still very active once the page cache has been filled. For
> specifics on the setup, I deliberately boot the box with 32G of RAM, and
> the dataset is 320G. My initial tests were with 1 320G file, but
> Johannes complained about that so I went to 32 10G files instead. That's
> what I'm currently using.
> 
> For the random test case, top of profile for kswapd is:
> 
> +   33.49%  kswapd0  [kernel.vmlinux]  [k] xas_create
> +    7.93%  kswapd0  [kernel.vmlinux]  [k] __isolate_lru_page
> +    7.18%  kswapd0  [kernel.vmlinux]  [k] unlock_page
> +    5.90%  kswapd0  [kernel.vmlinux]  [k] free_pcppages_bulk
> +    5.64%  kswapd0  [kernel.vmlinux]  [k] _raw_spin_lock_irqsave
> +    5.57%  kswapd0  [kernel.vmlinux]  [k] shrink_page_list
> +    3.48%  kswapd0  [kernel.vmlinux]  [k] __remove_mapping
> +    3.35%  kswapd0  [kernel.vmlinux]  [k] isolate_lru_pages
> +    3.14%  kswapd0  [kernel.vmlinux]  [k] __delete_from_page_cache

Here's the profile for the !mark_page_accessed() run, looks very much
the same:

+   32.84%  kswapd0  [kernel.vmlinux]  [k] xas_create
+    8.05%  kswapd0  [kernel.vmlinux]  [k] unlock_page
+    7.68%  kswapd0  [kernel.vmlinux]  [k] __isolate_lru_page
+    6.08%  kswapd0  [kernel.vmlinux]  [k] free_pcppages_bulk
+    5.96%  kswapd0  [kernel.vmlinux]  [k] _raw_spin_lock_irqsave
+    5.56%  kswapd0  [kernel.vmlinux]  [k] shrink_page_list
+    4.02%  kswapd0  [kernel.vmlinux]  [k] __remove_mapping
+    3.70%  kswapd0  [kernel.vmlinux]  [k] __delete_from_page_cache
+    3.55%  kswapd0  [kernel.vmlinux]  [k] isolate_lru_pages

-- 
Jens Axboe


  parent reply	other threads:[~2019-12-11 20:05 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
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 [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=d3ac2d74-f943-9b4c-570c-c7f6e86a475a@kernel.dk \
    --to=axboe@kernel.dk \
    --cc=clm@fb.com \
    --cc=david@fromorbit.com \
    --cc=hannes@cmpxchg.org \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=torvalds@linux-foundation.org \
    --cc=willy@infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.