From: Paolo Bonzini <pbonzini@redhat.com>
To: Alex Bligh <alex@alex.org.uk>, Mike Day <ncmike@ncultra.org>
Cc: peter.maydell@linaro.org, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] [RFC] Convert Qemu Timer List and Active Timers to RCU
Date: Thu, 13 Feb 2014 10:25:52 +0100 [thread overview]
Message-ID: <52FC8FA0.7090007@redhat.com> (raw)
In-Reply-To: <18FDD92C-F1BC-4D82-AA0C-9BC256503C06@alex.org.uk>
Il 13/02/2014 10:11, Alex Bligh ha scritto:
> Mike,
>
> On 12 Feb 2014, at 19:09, Mike Day wrote:
>
>> Allow readers to use RCU when reading Qemu timer lists. Applies to
>> Paolo Bonzini's RCU branch, https://github.com/bonzini/qemu/tree/rcu.
>>
>> This patch is for comment and review only. The rcu branch needs to be
>> rebased on upstream.
>
> I'll certainly have a look through this. However before I do, what
> problem is this trying to solve? Do we think there is possibility
> of contention on the active timers lock? I used to think this was
> taken (let alone contented) relatively infrequently, but Rob Herring's
> recent email suggests to me the list is being modified in some
> circumstances rather more frequently than I thought.
I think that, more than contention, it tries to reduce the cost of
synchronization primitives, especially the locking and unlocking of the
list around the invocation of timer callbacks.
Paolo
next prev parent reply other threads:[~2014-02-13 9:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-12 19:09 [Qemu-devel] [PATCH] [RFC] Convert Qemu Timer List and Active Timers to RCU Mike Day
2014-02-13 9:11 ` Alex Bligh
2014-02-13 9:25 ` Paolo Bonzini [this message]
2014-02-13 12:06 ` Mike Day
2014-02-13 12:57 ` Alex Bligh
2014-02-15 10:23 ` Alex Bligh
2014-02-15 20:33 ` Mike Day
2014-02-15 22:00 ` Alex Bligh
2014-02-17 16:13 ` Mike Day
2014-02-17 16:37 ` Alex Bligh
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