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From: David Howells <dhowells@redhat.com>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: dhowells@redhat.com, torvalds@linux-foundation.org,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	nicolas.dichtel@6wind.com, raven@themaw.net,
	Christian Brauner <christian@brauner.io>,
	keyrings@vger.kernel.org, linux-usb@vger.kernel.org,
	linux-block@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 07/10] pipe: Conditionalise wakeup in pipe_read() [ver #2]
Date: Thu, 31 Oct 2019 15:21:22 +0000	[thread overview]
Message-ID: <18022.1572535282@warthog.procyon.org.uk> (raw)
In-Reply-To: <fe167a90-1503-7ca2-4150-eeffd5cb1378@yandex-team.ru>

Konstantin Khlebnikov <khlebnikov@yandex-team.ru> wrote:

> > Only do a wakeup in pipe_read() if we made space in a completely full
> > buffer.  The producer shouldn't be waiting on pipe->wait otherwise.
> 
> We could go further and wakeup writer only when at least half of buffer is
> empty.  This gives better batching and reduces rate of context switches.
> 
> https://lore.kernel.org/lkml/157219118016.7078.16223055699799396042.stgit@buzz/T/#u

Yeah, I saw that.  I suspect that where you put the slider may depend on the
context.

David


  parent reply	other threads:[~2019-10-31 15:21 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-23 20:17 [RFC PATCH 00/10] pipe: Notification queue preparation [ver #2] David Howells
2019-10-23 20:17 ` [RFC PATCH 01/10] pipe: Reduce #inclusion of pipe_fs_i.h " David Howells
2019-10-23 20:17 ` [RFC PATCH 02/10] Remove the nr_exclusive argument from __wake_up_sync_key() " David Howells
2019-10-23 20:17 ` [RFC PATCH 03/10] Add wake_up_interruptible_sync_poll_locked() " David Howells
2019-10-23 20:17 ` [RFC PATCH 04/10] pipe: Use head and tail pointers for the ring, not cursor and length " David Howells
2019-10-26 14:58   ` [pipe] 6567a02d20: BUG:kernel_NULL_pointer_dereference,address kernel test robot
2019-10-27 14:03   ` [RFC PATCH 04/10] pipe: Use head and tail pointers for the ring, not cursor and length [ver #2] Linus Torvalds
2019-10-30 16:19   ` Ilya Dryomov
2019-10-30 20:35     ` Rasmus Villemoes
2019-10-30 22:16       ` Ilya Dryomov
2019-10-30 22:38         ` Rasmus Villemoes
2019-10-31 15:11     ` David Howells
2019-10-31 15:57       ` Ilya Dryomov
2019-11-01 14:53       ` David Howells
2019-10-31 14:57   ` David Howells
2019-11-03 11:17     ` Matthew Wilcox
2019-12-06 21:47   ` Johannes Hirte
2019-12-06 22:14     ` Linus Torvalds
2019-12-07  0:00       ` Johannes Hirte
2019-12-07  1:03         ` Linus Torvalds
2019-12-08 17:56           ` Johannes Hirte
2019-12-08 18:10             ` Linus Torvalds
2019-12-07  6:47         ` Linus Torvalds
2019-12-06 22:15   ` David Howells
2019-10-23 20:17 ` [RFC PATCH 05/10] pipe: Allow pipes to have kernel-reserved slots " David Howells
2019-10-23 20:18 ` [RFC PATCH 06/10] pipe: Advance tail pointer inside of wait spinlock in pipe_read() " David Howells
2019-10-23 20:18 ` [RFC PATCH 07/10] pipe: Conditionalise wakeup " David Howells
2019-10-27 15:57   ` Konstantin Khlebnikov
2019-10-31 15:21   ` David Howells [this message]
2019-10-31 16:38   ` David Howells
2019-11-03 11:04     ` Konstantin Khlebnikov
2019-10-23 20:18 ` [RFC PATCH 08/10] pipe: Rearrange sequence in pipe_write() to preallocate slot " David Howells
2019-10-23 20:18 ` [RFC PATCH 09/10] pipe: Remove redundant wakeup from pipe_write() " David Howells
2019-10-23 20:18 ` [RFC PATCH 10/10] pipe: Check for ring full inside of the spinlock in " David Howells
2019-10-24 10:32 ` [RFC PATCH 04/10] pipe: Use head and tail pointers for the ring, not cursor and length " David Howells
2019-10-24 13:14 ` [RFC PATCH 00/10] pipe: Notification queue preparation " Peter Zijlstra
2019-10-24 16:57 ` [RFC PATCH 11/10] pipe: Add fsync() support " David Howells
2019-10-24 21:29   ` Linus Torvalds
2019-10-25  8:34   ` David Howells
2019-10-27 15:22   ` Christoph Hellwig
2019-10-27 16:04   ` Konstantin Khlebnikov
2019-10-31 15:13   ` David Howells
2019-10-31 15:15   ` David Howells
2019-11-02 18:53     ` Linus Torvalds
2019-11-02 19:34     ` David Howells
2019-11-02 20:31       ` Andy Lutomirski
2019-11-02 22:03         ` Linus Torvalds
2019-11-02 22:09           ` Linus Torvalds
2019-11-02 22:30           ` Andy Lutomirski
2019-11-02 23:02             ` Linus Torvalds
2019-11-02 23:09               ` Linus Torvalds
2019-11-02 23:14                 ` Andy Lutomirski
2019-11-03 12:02                   ` Konstantin Khlebnikov

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