[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH v5 13/18] qht: support parallel writes

From: Emilio G. Cota
Subject: Re: [Qemu-devel] [PATCH v5 13/18] qht: support parallel writes
Date: Tue, 24 May 2016 20:10:04 -0400
User-agent: Mutt/1.5.23 (2014-03-12)

On Wed, May 25, 2016 at 01:17:21 +0300, Sergey Fedorov wrote:
> >> With this implementation we could:
> >>  (1) get rid of qht_map::stale
> >>  (2) don't waste cycles waiting for resize to complete
> > I'll include this in v6.
> How is it by perf?

Not much of a difference, since resize is a slow path. Calling
qht-bench with lots of update and resize threads performs very
poorly either way =D

I like the change though because using the mutex here simplifies
the resize code; there's no guilt anymore attached to holding the lock
for some time (e.g. when allocating a new, possible quite large,
map), whereas with the spinlock we would allocate it before
acquiring the lock, without knowing whether the allocation would
be needed in the end.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]