Subject: Re: NetBSD 1.4.1 - Clock stops when doing I/O
To: Paul Sander <paul@wakawaka.com>
From: Chas Williams <chas@cmf.nrl.navy.mil>
List: port-mac68k
Date: 01/04/2000 08:09:56
In message <200001042148.NAA13766@bugs.wakawaka.com>,Paul Sander writes:
>>	1. Is there something broken on the Q840 that would slow down
>>	the CPU and/or I/O?  any options that I should be setting?
>
>>	2. Why does the clock behave so badly?  If this is a known
>>	problem in 1.4.1, will it be fixed in the (soon to be releaed??)
>>	1.4.2?

the timer interrupts dont have priority over the i/o interrupts.  since
the disk driver needs to disable interrupts you tend to 'lose time'
the 840 is paritcularly bad in this respect (if i remember right) since
the disk driver for the 840 doesnt support dma at this time.  i was
running an 840 for a while but switched back to my 800 since heavy
disk i/o would just cripple the system.