From: Andres Freund <andres@anarazel.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org
Subject: Re: [PATCHSET v5 0/12] Add support for async buffered reads
Date: Fri, 5 Jun 2020 16:02:44 -0700 [thread overview]
Message-ID: <20200605230244.u342xw4negic2nmr@alap3.anarazel.de> (raw)
In-Reply-To: <0179d0bf-0b01-3f05-9221-654a00f0452d@kernel.dk>
Hi,
On 2020-06-05 16:56:44 -0600, Jens Axboe wrote:
> On 6/5/20 4:54 PM, Andres Freund wrote:
> > On 2020-06-05 16:49:24 -0600, Jens Axboe wrote:
> >> Yes that's expected, if we have to fallback to ->readpage(), then it'll
> >> go to a worker. read-ahead is what drives the async nature of it, as we
> >> issue the range (plus more, depending on RA window) as read-ahead for
> >> the normal read, then wait for it.
> >
> > But I assume async would still work for files with POSIX_FADV_RANDOM
> > set, or not? Assuming the system wide setting isn't zero, of course.
>
> Yes it'll work if FADV_RANDOM is set.
Cool.
> But just not if read-ahead is totally disabled. I guess we could make
> that work too, though not sure that it's super important.
It's not from my end. I was just trying to check if the reduced
performance I saw was related to interactions between PG prefetching and
kernel level prefetching. And changing the /sys entry seemed easier than
making postgres set POSIX_FADV_RANDOM...
Greetings,
Andres Freund
next prev parent reply other threads:[~2020-06-05 23:02 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-26 19:51 [PATCHSET v5 0/12] Add support for async buffered reads Jens Axboe
2020-05-26 19:51 ` [PATCH 01/12] block: read-ahead submission should imply no-wait as well Jens Axboe
2020-05-26 19:51 ` [PATCH 02/12] mm: allow read-ahead with IOCB_NOWAIT set Jens Axboe
2020-05-26 20:45 ` Johannes Weiner
2020-05-26 19:51 ` [PATCH 03/12] mm: abstract out wake_page_match() from wake_page_function() Jens Axboe
2020-05-26 21:02 ` Johannes Weiner
2020-06-01 14:16 ` Matthew Wilcox
2020-05-26 19:51 ` [PATCH 04/12] mm: add support for async page locking Jens Axboe
2020-05-26 21:59 ` Johannes Weiner
2020-05-26 22:01 ` Jens Axboe
2020-05-27 16:02 ` Johannes Weiner
2020-06-01 14:26 ` Matthew Wilcox
2020-06-01 17:15 ` Jens Axboe
2020-05-26 19:51 ` [PATCH 05/12] mm: support async buffered reads in generic_file_buffered_read() Jens Axboe
2020-05-26 22:00 ` Johannes Weiner
2020-05-26 19:51 ` [PATCH 06/12] fs: add FMODE_BUF_RASYNC Jens Axboe
2020-05-26 19:51 ` [PATCH 07/12] ext4: flag as supporting buffered async reads Jens Axboe
2020-05-26 19:51 ` [PATCH 08/12] block: flag block devices as supporting IOCB_WAITQ Jens Axboe
2020-05-26 19:51 ` [PATCH 09/12] xfs: flag files as supporting buffered async reads Jens Axboe
2020-05-28 17:53 ` Darrick J. Wong
2020-05-28 19:23 ` Jens Axboe
2020-05-26 19:51 ` [PATCH 10/12] btrfs: " Jens Axboe
2020-05-26 19:57 ` Chris Mason
2020-05-26 19:51 ` [PATCH 11/12] mm: add kiocb_wait_page_queue_init() helper Jens Axboe
2020-05-26 22:01 ` Johannes Weiner
2020-05-26 19:51 ` [PATCH 12/12] io_uring: support true async buffered reads, if file provides it Jens Axboe
2020-05-28 17:02 ` [PATCHSET v5 0/12] Add support for async buffered reads Sedat Dilek
2020-05-28 17:02 ` Sedat Dilek
2020-05-28 17:06 ` Jens Axboe
2020-05-28 17:12 ` Sedat Dilek
2020-05-28 17:12 ` Sedat Dilek
2020-05-28 17:14 ` Jens Axboe
2020-05-28 18:20 ` Sedat Dilek
2020-05-28 18:20 ` Sedat Dilek
2020-05-29 10:02 ` Sedat Dilek
2020-05-29 10:02 ` Sedat Dilek
2020-05-29 11:22 ` Sedat Dilek
2020-05-29 11:22 ` Sedat Dilek
2020-05-30 13:36 ` Sedat Dilek
2020-05-30 13:36 ` Sedat Dilek
2020-05-30 18:57 ` Sedat Dilek
2020-05-30 18:57 ` Sedat Dilek
2020-05-31 1:57 ` Jens Axboe
2020-05-31 7:04 ` Sedat Dilek
2020-05-31 7:04 ` Sedat Dilek
2020-05-31 7:12 ` Sedat Dilek
2020-05-31 7:12 ` Sedat Dilek
2020-06-01 13:35 ` Sedat Dilek
2020-06-01 13:35 ` Sedat Dilek
2020-06-01 14:04 ` Jens Axboe
2020-06-01 14:13 ` Sedat Dilek
2020-06-01 14:13 ` Sedat Dilek
2020-06-01 14:14 ` Jens Axboe
2020-06-01 14:35 ` Jens Axboe
2020-06-01 14:43 ` Sedat Dilek
2020-06-01 14:43 ` Sedat Dilek
2020-06-01 14:46 ` Jens Axboe
2020-06-01 14:51 ` Sedat Dilek
2020-06-01 14:51 ` Sedat Dilek
2020-06-01 20:18 ` Sedat Dilek
2020-06-01 20:18 ` Sedat Dilek
2020-06-04 0:59 ` Andres Freund
2020-06-04 1:04 ` Jens Axboe
2020-06-04 1:30 ` Andres Freund
2020-06-05 19:56 ` Andres Freund
2020-06-05 14:42 ` Jens Axboe
2020-06-05 20:20 ` Andres Freund
2020-06-05 20:21 ` Jens Axboe
2020-06-05 20:36 ` Andres Freund
2020-06-05 20:53 ` Jens Axboe
2020-06-05 21:13 ` Jens Axboe
2020-06-05 21:21 ` Jens Axboe
2020-06-05 22:30 ` Andres Freund
2020-06-05 22:36 ` Andres Freund
2020-06-05 22:49 ` Jens Axboe
2020-06-05 22:54 ` Andres Freund
2020-06-05 22:56 ` Jens Axboe
2020-06-05 23:02 ` Andres Freund [this message]
2020-06-06 0:33 ` Sedat Dilek
2020-06-06 0:33 ` Sedat Dilek
2020-06-06 16:04 ` Jens Axboe
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