linux-kernel - Re: [RFC PATCH 07/10] pipe: Conditionalise wakeup in pipe

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Message-ID: <18022.1572535282@warthog.procyon.org.uk>
Date:   Thu, 31 Oct 2019 15:21:22 +0000
From:   David Howells <dhowells@...hat.com>
To:     Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
Cc:     dhowells@...hat.com, torvalds@...ux-foundation.org,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        nicolas.dichtel@...nd.com, raven@...maw.net,
        Christian Brauner <christian@...uner.io>,
        keyrings@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-block@...r.kernel.org, linux-security-module@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-api@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 07/10] pipe: Conditionalise wakeup in pipe_read() [ver #2]

Konstantin Khlebnikov <khlebnikov@...dex-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