From: lee@dlpco.dlpco.COM (Lee Penn )
Subject: Performance issues revisited
Resent-From: mmdf@xenitec.on.ca
Submit-To: scogen@xenitec.on.ca
Organization: [resent by] The SCOGEN gateway and Propagation Society
Date: Mon, 21 Dec 1992 20:33:24 GMT
Precedence: bulk

This did not make it thru to mike via direct address, so thought I would
just shoot it back thru scogen.

Mike: There was a very long series of messages about machines being
upgraded to more than 16 Megs RAM and the secondary cache memory.  
Have your friend check to see if his machine as 64K of cache or 
256K.  He NEEDS 256k and I suspect that if he has only a 64k cache
that that is the problem as only the lover 16 megs are being cached
and the upper 16 megs are being accessed at a snail's pace.

On another machine that I worked with, we found out that the hard
drive was the bottleneck.  I used the following command as a quick 
test to see about the bytes/second off the drive and found it very
very slow.

        time dd if=/dev/rhd0a of=/dev/null bs=2048 count=8192

This is a 16 meg copy to /dev/null.  On a lively machine, I expect
to see 1 Megabyte/second or better.  On my customer's machine, we
were getting around 200 K/sec.  Replaced the drive and he came back
up to speed.

These are my two thoughts, good luck.


>This posting is on behalf of a friend of mine who is having a problem
>with an SCO UNIX upgrade.  A customer of his originally had a 486/33
>with 16M of memory and a 1G SCSI drive.  Recently, the system was upgraded
>to a 486/50 with 32M of memory and an additional 1G drive was added. The
>upgrade was principally done because the customer wanted to network their
>existing PCs with the UNIX box (using PC-Interface by Locus) so that
>their business could be put "under one roof". Unfortunately, the system
>is now crawling along at a snail's pace.

>Oh, yes, before I forget, it's a pretty standard box. UNIX 3.2v4.1,
>has a Bustek SCSI, and I believe a couple of Equinox 24-port boards.
>They currently have about 30 or so dumb terminals, about 15 PCs and
>around 8 printers (HPLJs and CI line printers).

>I've taken a brief look around, and things seem to be in order. They've
>got all of their UNIX stuff on one disk, and all of their DOS stuff on
>the other. The "standard" kernel paramters seem to be reasonable (NBUF,
>NHBUF, NINODE, etc.) and sar never seems to show anything outrageous
>(cpu time, cache hits, etc.) and the system has never swapped any processes
>out. However, users are complaining that when they start some applications
>(the most frequent complaint is about Lotus 123) -- even when there are
>very few people using the machine, such as on the weekend -- things will
>periodically slow to a crawl.  There haven't been any panics or warnings,
>just lethargy.  A reboot seems to clear things up temporarily.

>His next step is to "camp out" on the box, but I thought that I would
>ask you good folks for any and all suggestions. I seem to (fuzzily) recall
>a discussion about poor system performance when memory was increased, but
>I don't know if it applies here.  Your input is greatly appreciated, and
>may help Rob from getting any more gray hairs. :-)

>-- 
>Mike Stefanik  mike@pacsoft.com  ...!uunet!pacsoft!mike  (909) 681-2623
>Pacific Software Group, Riverside, CA
================================================================================
Lee Penn,  DLP Technologies, Inc.                     Voice: 513 232-7791
SCO Advanced Product Center                           FAX: (513) 232-7801
7444 Jager Ct.
Cincinnati, OH  45230-4344                           email: lee@dlpco.COM

================================================================================
Lee Penn,  DLP Technologies, Inc.                     Voice: 513 232-7791
SCO Advanced Product Center                           FAX: (513) 232-7801
7444 Jager Ct.
Cincinnati, OH  45230-4344                           email: lee@dlpco.COM