Subject: Re: [PATCH] ppc44x: support for 256K PAGE_SIZE

From: Yuri Tikhonov <[email-masked]>
Date: Fri, 19 Oct 2007 19:37:23 +0400

On Friday 19 October 2007 03:21, Paul Mackerras wrote:
> Have you measured the performance using a 64kB page size?  If so, how
> does it compare with the 256kB page size?

 I measured the performance of the sequential full-stripe write operations to
a RAID-5 array (P values below are in MB per second) using the h/w accelerated
RAID-5 driver.

 Here are the comparative results for the different PAGE_SIZE values:

PAGE_SIZE = 4K:
 P = 66 MBps;

PAGE_SIZE = 16K:
 P = 145 MBps;

PAGE_SIZE = 64K:
 P = 196 MBps;

PAGE_SIZE = 256K:
 P = 217 MBps.

> The 64kB page size has the attraction that no binutils changes are
> required.

 That's true, but the additional performance is an attractive thing too.

> Paul.

-- 
Yuri Tikhonov, Senior Software Engineer
Emcraft Systems, www.emcraft.com