Re: kernels and b0xen

[Michel Lanners <mlan@cpu.lu>]

On  22 Jan, this message from simon@nuit.ca echoed through cyberspace:

>> - check your hard disk speed: hdparm -tT /dev/<disk with kernel source>
>>   (is non-destructive; post the result to compare)
> 
> 1.  Timing buffer-cache reads:   128 MB in  3.73 seconds = 34.32 MB/sec
>  Timing buffered disk reads:  64 MB in 18.10 seconds =  3.54 MB/sec
> 
> 2. /dev/sda:
>  Timing buffer-cache reads:   128 MB in  3.68 seconds = 34.78 MB/sec
>   Timing buffered disk reads:  64 MB in 12.71 seconds =  5.04 MB/sec

34 MB/sec for buffered reads s essentially a measure of memory
bandwidth. And 34 MB/sec seems low for a 7500-class machine. I get 45
MB/sec (OK, on an interleaved memory config).

3.54 MB/sec for disk is low; 5.04 is about acceptable for an older SCSI
disk. Unfortunately Apple fitted those systems with _horrible_ disks
(like the Quantum Fireball TM's).

On my IDE disk in the 7600, connected to a Promise IDE controller, I get
12 MB/sec. That _does_ help a lot for kernel compiles.

Cheers

Michel

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