From: Yuri Tikhonov <yur@emcraft.com>
To: Kumar Gala <galak@kernel.crashing.org>
Cc: linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH] ppc44x: support for 256K PAGE_SIZE
Date: Fri, 19 Oct 2007 20:03:28 +0400 [thread overview]
Message-ID: <200710192003.28143.yur@emcraft.com> (raw)
In-Reply-To: <D3506DCC-01F5-48C1-900D-2D827AB6BE19@kernel.crashing.org>
On Friday 19 October 2007 19:48, Kumar Gala wrote:
> > PAGE_SIZE = 4K:
> > P = 66 MBps;
> >
> > PAGE_SIZE = 16K:
> > P = 145 MBps;
> >
> > PAGE_SIZE = 64K:
> > P = 196 MBps;
> >
> > PAGE_SIZE = 256K:
> > P = 217 MBps.
>
> Is this all in kernel space? or is there a user space aspect to the
> benchmark?
The situation here is that the Linux RAID driver does a lot of complex things
with the pages (strips of array) using CPU before submitting these pages to h/w.
Here is where the most time is spent. Thus, increasing the PAGE_SIZE value we reduce
the number of these complex algorithms calls needed to process the whole test (writing
the fixed number of MBytes to RAID array). So, there are no user space aspects.
--
Yuri Tikhonov, Senior Software Engineer
Emcraft Systems, www.emcraft.com
next prev parent reply other threads:[~2007-10-19 16:06 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-18 7:08 [PATCH] ppc44x: support for 256K PAGE_SIZE Yuri Tikhonov
2007-10-18 10:44 ` Josh Boyer
2007-10-18 11:45 ` Benjamin Herrenschmidt
2007-10-18 12:01 ` Josh Boyer
2007-10-18 12:12 ` Benjamin Herrenschmidt
2007-10-18 13:25 ` Yuri Tikhonov
2007-10-23 14:00 ` Segher Boessenkool
2007-10-18 13:18 ` Yuri Tikhonov
2007-10-18 13:25 ` Josh Boyer
2007-10-18 13:30 ` Yuri Tikhonov
2007-10-18 14:41 ` Josh Boyer
2007-10-18 23:21 ` Paul Mackerras
2007-10-19 13:24 ` Kumar Gala
2007-10-22 16:12 ` Yuri Tikhonov
2007-10-23 13:59 ` Segher Boessenkool
2007-10-23 23:08 ` Paul Mackerras
2007-10-23 23:15 ` Paul Mackerras
2007-10-19 15:37 ` Yuri Tikhonov
2007-10-19 15:48 ` Kumar Gala
2007-10-19 16:03 ` Yuri Tikhonov [this message]
2007-10-19 16:36 ` Josh Boyer
2007-10-19 19:04 ` Wolfgang Denk
-- strict thread matches above, loose matches on Subject: below --
2007-10-18 11:00 Yuri Tikhonov
2007-10-18 11:47 ` Benjamin Herrenschmidt
2007-10-18 13:20 ` Yuri Tikhonov
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