Does cache memory size 512K over 256K matter?

Does cache memory size 512K over 256K matter?

Post by Dan Crome » Wed, 17 Jul 1996 04:00:00



Hello,
     Our organization ordered a machine with 512K 2nd-level cache.  Our
supplier, S.A.G. Electronics, substituted the Tyan motherboard we ordered
with an Intel Triton II motherboard, with 256K cache.  Will the smaller
2nd-level cache have a significant impact when running FreeBSD or Linux
with 64MB RAM?

Dan

 
 
 

Does cache memory size 512K over 256K matter?

Post by BOFH » Thu, 18 Jul 1996 04:00:00


: Hello,
:      Our organization ordered a machine with 512K 2nd-level cache.  Our
: supplier, S.A.G. Electronics, substituted the Tyan motherboard we ordered
: with an Intel Triton II motherboard, with 256K cache.  Will the smaller
: 2nd-level cache have a significant impact when running FreeBSD or Linux
: with 64MB RAM?

Significant? Probably not.. As far as the board, I've got Triton's in
use and they're not that bad. They support higher cache levels if you
really feel the need.

 
 
 

Does cache memory size 512K over 256K matter?

Post by Ken Bigelo » Sun, 21 Jul 1996 04:00:00



> Hello,
>      Our organization ordered a machine with 512K 2nd-level cache.  Our
> supplier, S.A.G. Electronics, substituted the Tyan motherboard we ordered
> with an Intel Triton II motherboard, with 256K cache.  Will the smaller
> 2nd-level cache have a significant impact when running FreeBSD or Linux
> with 64MB RAM?

> Dan

I doubt if size will make too much difference, but speed very definitely
will. I hope you're running no more than 15 ns chips (12 would be better
with high-speed motherboards). I've had major problems with 20 ns cache
chips until I slowed down the cache read cycle. FreeBSD seems to be more
efficient than DOS or Windoze, so it tries to access the cache before the
data is necessarily stable.   :-(
--

Ken

Are you interested in   |
byte-sized education    |   http://www.play-hookey.com
over the Internet?      |

 
 
 

Does cache memory size 512K over 256K matter?

Post by Brian Some » Wed, 24 Jul 1996 04:00:00


[relevent stuff deleted]
: I doubt if size will make too much difference, but speed very definitely
: will.
[The rest of the relevent stuff delted]

I wouldn't let your partner hear that ! ;-)

--

Don't _EVER_ lose your sense of humour....

 
 
 

Does cache memory size 512K over 256K matter?

Post by Don Yunisk » Thu, 25 Jul 1996 04:00:00





>[relevent stuff deleted]
>: I doubt if size will make too much difference, but speed very definitely
>: will.
>[The rest of the relevent stuff delted]

>I wouldn't let your partner hear that ! ;-)

(grin)

Seriously, I think you're getting to the point of diminishing returns
when cache size gets up there.  I don't *think* (OK, flame me *here* :>)
that any of these OS's particularly try to load the kernel and lock
the cache (etc.) or other similar *potential* optimizations (it's
doubtful whether any such broad-brush optimization would be the most
efficient use of the cache, anyway).  It would be possible to
make such refinements for a particular "kernel" in a particular
set of circumstances, etc.

Of course, if money is no object (email and I'll send you the address
of my PO Box!  :>), more is "always" better...

 
 
 

Does cache memory size 512K over 256K matter?

Post by James Rayna » Thu, 25 Jul 1996 04:00:00




>Seriously, I think you're getting to the point of diminishing returns
>when cache size gets up there.  I don't *think* (OK, flame me *here* :>)
>that any of these OS's particularly try to load the kernel and lock
>the cache (etc.) or other similar *potential* optimizations (it's

This is getting dangerously off-topic, but the QNX microkernel fits
neatly into the cache on a 486 (all 8k of it).

Obviously, trying to trim the FreeBSD kernel down to 8kB is perhaps a
little extreme, but 256k or 512k may not be totally impossible and
might be of interest to the embedded controller world.  Has anyone
ever tried this?

(I've taken comp.os.linux.hardware out of follow-ups to reduce the
risk of a "mine's smaller than yours" flamewar ;-)

--
James Raynard, Edinburgh, Scotland

http://www.freebsd.org/~jraynard/

 
 
 

Does cache memory size 512K over 256K matter?

Post by Rob( » Fri, 26 Jul 1996 04:00:00





><useful stuff about cache sizes cut so I can interject a snide remark>

>;
>; Of course, if money is no object (email and I'll send you the
address
>; of my PO Box!  :>), more is "always" better...

>My boss used to tell me:

>    If some is good, and more is better, then too much is just
enough.

>clint

>--
>Underscores added to return address to defeat advertising engines.


>/* The gene pool could use a little chlorine. */
>668: The Neighbor of the Beast  -- Emo Phillips

Yes it does. Go to the intel homepage and look at the processor specs.

It seems that up to a p5 133 , 256k works good ,
then when they have a p5 150 with 512k then the speed increase
for the 150 is very small over the 133, the extra cache was needed to
get the little bump in extra speed. Which implies that the motherboard
has trouble keeping up with the chip. Or that the Pentium at that speed
is outgrowing the speed of the motherboard.

Anyhow anything after a p150 requires 512k of cache  to get the
necessary jump in system speed over the lower speed processor.
However, for all practical purposes the p133 and p150 will have the
same performance.

For instance , from the Intel graph it is a no-brainer to infer
that a p150 with 256k cache would probably be slower than a p133,
probably due to the p133 system board running at 66mhz and the
p150's at 60mhz.

It seems that even a 200mhz Pentium is pushing the motherboard a little
too much, and that getting anything over a p166 is probably and
currently spending too much money.

It you have plans to get a 200mhz Pentium , it may be in your interest
to get a barnyard door cheap Pentium Pro instead.

 
 
 

Does cache memory size 512K over 256K matter?

Post by Clint Wolf » Fri, 26 Jul 1996 04:00:00


<useful stuff about cache sizes cut so I can interject a snide remark>

;
; Of course, if money is no object (email and I'll send you the address
; of my PO Box!  :>), more is "always" better...

My boss used to tell me:

        If some is good, and more is better, then too much is just enough.

clint

--
Underscores added to return address to defeat advertising engines.


/* The gene pool could use a little chlorine. */
668: The Neighbor of the Beast  -- Emo Phillips

 
 
 

1. 256k cache vs 512k cache

I'm currently running Linux on a 386/20 with 8 megs RAM.
I'm thinking about buying a Pentium 166 or 200 with either
16 Megs or 32 Megs of RAM to run Linux on.  I will be working
on a personal project adding another IPC mechanism that will
cluster several Linux boxes together.  I will be using X
extensively, and recompiling the kernel often.

A mail order vendor I have found sells the P200 for a great
price, but the cache is 256k and not upgradable to 512k.
With the type of work I'll be doing, will it make much of
a difference?

On a similar note regarding monitors ... is .27 dot pitch
hard on the eyes?  I don't seem to notice a great difference
when looking at them at Fry's.  The price difference between
.25 and .27 seems to be a lot, but I don't want to
strain my eyes for the sake of saving a few bucks.  
I don't know what the pitch is on my Sun monitor at work is,
but it is acceptable to me.

Thanks in advance!

Jeff

2. How good is linux on a alpha (axp)

3. Pentium 120 MHz+512K cache, or 133+256K cache??

4. ksh-awk script problem

5. 512K cache vs. 256K cache

6. getch() function in AIX

7. People with 32MB of RAM, how much cache do you have (256k/512k)??

8. UUCP Snag

9. 256k -> 512k cache upgrade is it worth $$?

10. 256K v. 512K cache

11. 256k cache vs 512k?

12. PPro 256K L2 cache and memory > 64M

13. ???---RAM vs cache : is 256k cache enough for 24M RAM ---???