Re: System performance with more RAM than can be cached

Dietmar Braun (dietmar@highway.bertelsmann.de)
Fri, 4 Jul 1997 21:53:40 +0200

From: Nigel Metheringham <Nigel.Metheringham@ThePLAnet.net>
I have access to a batch of P120 boxes that are available for me to use up
as servers - I aim to run news or squid web cache on them...
They can physically take 128MB RAM.
They have 256KB L2 cache soldered onto the motherboard - this cannot be
upgraded.
*Only* 64MB can be cached by the L2.

[The motherboards are 8500TVX if that makes a difference]

Normally I would throw as much RAM at the problem as I can.
However would increasing the RAM above the 64MB cachable area cause
performance to go down the toilet?

Hi,

when i upgraded my machine to 128MB, i had to upgrade the tag-ram too
and did some measurements and found
that complete kernel build took 30% longer without tag-ram.

I think 30% is tolerable and it might be even less with 256k (i have 512k)
cache. For squid or news 128 MB will be badly needed.

I dunno how comparable these numbers are between motherboards.

regards
Dietmar

-- 
Reporter (to Mahatma Gandhi): Mr Gandhi, what do you think of Western
Civilization?  Gandhi: I think it would be a good idea.
Dietmar Braun, E-Mail: braun@highway.bertelsmann.de;