From: Peter Zijlstra <peterz@infradead.org>
To: edwin <edwintorok@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>,
rml@tech9.net, Linux Kernel <linux-kernel@vger.kernel.org>,
"Thomas Gleixner mingo@redhat.com" <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: Quad core CPUs loaded at only 50% when running a CPU and mmap intensive multi-threaded task
Date: Mon, 25 Aug 2008 13:41:17 +0200 [thread overview]
Message-ID: <1219664477.8515.54.camel@twins> (raw)
In-Reply-To: <48B290E7.4070805@gmail.com>
On Mon, 2008-08-25 at 14:00 +0300, edwin wrote:
> Peter Zijlstra wrote:
> > Right - does it make sense to teach clamav about pread() ?
>
> If it is preferred over mmap, then maybe yes.
I would certainly consider this for small (< 1M?) files. With mmap the
faults and pte overhead aren't free either, and the extra memcpy from
pread() isn't that much.
next prev parent reply other threads:[~2008-08-25 11:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <48B1CC15.2040006@gmail.com>
2008-08-25 5:51 ` Quad core CPUs loaded at only 50% when running a CPU and mmap intensive multi-threaded task Peter Zijlstra
2008-08-25 7:04 ` edwin
2008-08-25 9:23 ` Peter Zijlstra
2008-08-25 9:49 ` Török Edwin
2008-08-25 10:02 ` Peter Zijlstra
2008-08-25 10:22 ` Török Edwin
2008-08-25 10:36 ` Peter Zijlstra
2008-08-25 11:00 ` edwin
2008-08-25 11:30 ` edwin
2008-08-25 11:41 ` Peter Zijlstra [this message]
2008-08-25 13:48 ` Theodore Tso
2008-08-26 8:12 ` Andi Kleen
2008-09-08 19:10 ` Török Edwin
2008-09-12 19:16 ` mmap/munmap latency on multithreaded apps, because pagefaults hold mmap_sem during disk read Török Edwin
2008-09-12 19:16 ` Török Edwin
2008-09-12 19:35 ` Mike Waychison
2008-09-12 19:35 ` Mike Waychison
2008-09-12 20:10 ` Török Edwin
2008-09-12 20:10 ` Török Edwin
2008-08-25 10:37 ` Quad core CPUs loaded at only 50% when running a CPU and mmap intensive multi-threaded task Peter Zijlstra
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