From: Arjan van de Ven <arjanv@redhat.com>
To: Etienne Lorrain <etienne_lorrain@yahoo.fr>
Cc: linux-kernel@vger.kernel.org
Subject: Re: memset (was: Redundant memset in AIO read_events)
Date: 10 Jul 2003 12:19:21 +0200 [thread overview]
Message-ID: <1057832361.5817.2.camel@laptop.fenrus.com> (raw)
In-Reply-To: <20030710100417.83333.qmail@web11801.mail.yahoo.com>
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On Thu, 2003-07-10 at 12:04, Etienne Lorrain wrote:
> Note that using memset() is better reserved to initialise variable-size
> structures or buffers. Even if memset() is extremely optimised,
> it is still not as fast as not doing anything.
this is not always true....
memset can be used as an optimized cache-warmup, which can avoid the
write-allocate behavior of normal writes, which means that if you memset
a structure first and then fill it, it can be halve the memory bandwidth
and thus half as fast. This assumes an optimized memset which we
*currently* don't have I think... but well, we can fix that ;)
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next prev parent reply other threads:[~2003-07-10 10:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-10 10:04 Etienne Lorrain
2003-07-10 10:19 ` Arjan van de Ven [this message]
[not found] <20030710100417.83333.qmail@web11801.mail.yahoo.com.suse.lists.linux.kernel>
[not found] ` <1057832361.5817.2.camel@laptop.fenrus.com.suse.lists.linux.kernel>
2003-07-10 10:29 ` Andi Kleen
2003-07-10 10:33 ` Arjan van de Ven
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