Subject: Re: Slow crash dump performance
To: Matthias Scheler <tron@zhadum.de>
From: David Laight <david@l8s.co.uk>
List: port-sparc64
Date: 04/02/2005 17:13:37
On Sat, Apr 02, 2005 at 03:51:08PM +0000, Matthias Scheler wrote:
> 
> why does an ULTRA60 with 1GB of main memory need half an hour (estimated)
> to write a kernel crash dump? Solaris can do that a lot faster.

Solaris might only be writing the pages mapped into kernel space, not
the whole 1GB.

1GB in 30mins = 1GB in 1800 secs = 1MB in 1.8 secs ~= 550kB/s
Looks like slow PIO transfers or a lot of time waiting for the the
disk to rotate - possibly made worse by small transfers.

	David

-- 
David Laight: david@l8s.co.uk