Date: Sat, 9 Jul 2005 08:03:30 -0400
Reply-To: MC <supermario@MAC.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: MC <supermario@MAC.COM>
Subject: Re: SAS 9.1 XP not using RAM
Thanks for your reply. This option does look promising. I will post my
results after turning this on.
I am thinking on setting up the buffsize to 81920 (5x the data set page
size) and bufno of 20 to see if that helps with SGIO.
On Fri, 8 Jul 2005 15:29:59 -0400, Joe Whitehurst
>Take a look at the SGIO option as well as the features mentioned in the
>section of the V9 Companion for Windows entitled Windows features that
>SGIO is probably the single most important option to consider:
>The SGIO system option greatly improves I/O performance for SAS I/O files
>(data sets, catalogs, indexes, utility files, and other I/O files) when
>PC has a large amount of RAM. Scatter-read / gather-write bypasses
>intermediate buffer transfers between memory and disk.
>When SGIO is active, SAS uses the number of buffers that are specified by
>the BUFNO system option to transfer data between disk and RAM. I/O
>performance usually improves as the value for the BUFNO increases. Try
>different values of the BUFNO system option to tune each SAS job or DATA
>The scatter-read / gather-write feature is active only for SAS I/O files
>contain a 4K-multiple pagesize (for example, 4096 or 8192) on 32-bit
>contain a 8K-multiple pagesize (for example, 8192 or 16384) on 64-bit
>were not created by using Version 6 of the SAS System
>are accessed sequentially.
>If an I/O file does not meet these criteria, SGIO is inactive for that
>even though the SGIO option is specified.
>To use the SGIO system option on Windows NT, you must install Service Pack
>From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of MC
>Sent: Friday, July 08, 2005 2:00 PM
>Subject: SAS 9.1 XP not using RAM
>I was wondering if anyone has seen this before or could give me some ideas
>on how to fix it.
>The server has:
>Dual Xeon at 2.6GHZ
>4GB of RAM
>1 page file on the C drive 2GB
>1 page file on the E drive 4GB
>Running XP SP1.
>We are pulling a 20GB dataset from a network location using a data step.
>SAS, instead of using RAM, is doing everything by paging. No RAM is
>used except for system stuff (by looking at the Task Manager, only 252MB
>Looking at the "performance" app, the pc is doing about 2920 pages/sec.
>Available Mbyes is 3253MB.
>% usage of page file on C drive is 0.7
>% usage of page file on e drive is 0.4
>Any ideas what needs to be changed? Any options?
>The dat set page size is 16384
>number of data set pages is 1041784
>Observations is 8334252
>Variables is 294
>Observation length is 1824.
>I have tried setting the buffsize to 81920 and bufno to 10 but nothing
>to change in the performance.
>Thanks in advance,