Subject: devel-digest V2 #217
From: [email-masked] (devel-digest)
To: [email-masked]

devel-digest           Friday, July 9 1999           Volume 02 : Number 217

In this issue:

    Re: memory bandwidth problems
    Re: memory bandwidth problems

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Date: Thu, 08 Jul 1999 09:48:58 +0200
From: Jan Rinze <[email-masked]>
Subject: Re: memory bandwidth problems

"Andrew E. Mileski" wrote:

> Mark Lord wrote:
> > On a similar vein:
> >
> >         [root@windy /root]# hdparm -T /dev/hda
> >
> >         /dev/hda:
> >          Timing buffer-cache reads:   64 MB in  1.23 seconds =52.03 MB/sec
> >
> > Compare that with a P2-400/SDRAM system:
> >         Timing buffer-cache reads:   128 MB in  1.12 seconds =114.29 MB/sec
>
> Try that in PIO mode.
>
> --
> Andrew E. Mileski - Software Engineer
> Rebel.com  http://www.rebel.com/

The StrongARM does this with 16 k data cache and no secondary cache !
(Pentium II : 512 Kb)
it has only 278 Mhz clock , ( as opposed to 400 Mhz pentium II)
Also the StrongARM has a 32 bit wide bus running at 66 Mhz.

(just for comparison)

this configuration is exactly the same when you look at performance.
2*(100/66)*(400/278) *(52.03)= 113.5 .

Your system should be running at 30 Watt then ..........
( twice the power consumption of the Netwinder.)
Does it ?

Let's hope Intel's new StrongARM has 100 Mhz bus or more
and has 64 bit wide access. ( running at 600 Mhz.)
Do the calculations yourself for such a system .... ;-)

Jan Rinze.

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------------------------------

Date: Thu, 08 Jul 1999 22:19:03 -0400
From: Mark Lord <[email-masked]>
Subject: Re: memory bandwidth problems

"Andrew E. Mileski" wrote:
> 
> Mark Lord wrote:
> > On a similar vein:
> >
> >         [root@windy /root]# hdparm -T /dev/hda
> >
> >         /dev/hda:
> >          Timing buffer-cache reads:   64 MB in  1.23 seconds =52.03 MB/sec
> >
> > Compare that with a P2-400/SDRAM system:
> >         Timing buffer-cache reads:   128 MB in  1.12 seconds =114.29 MB/sec
> 
> Try that in PIO mode.

Irrelevant.  "-T" does not actually perform I/O.
It just measures memory bandwidth to/from the Linux buffer system.

Cheers
- -- 
[email-masked]

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