Re: FastSCSI on WarpEngine
On Tue, Mar 04, 2003 at 02:23:07PM +0100, Richard Zidlicky wrote:
> > I would like to see around 4-6 MB/s coming out of the disks on that machine,
> > so I wonder how to achieve this. Maybe the mentioned change in the source
> > code from 50 to 25 would be a way. Instead of facing the frontier and risk
> > data corruption with 10 MHz transfer a value of 37 could mean 7.5 MHz
> > transfers... don't know whether this might work or not...
> Hm.. I get only 3.3 MB/s peak performance and perhaps 2 MB/s realistic
> performance on my 68060 with an IDE disk, would be interesting to see
> a few more datapoints. Iirc my IDE is on something like a 10 MHz bus.
Yeah, but it's IDE and when I saw IDE performance in crest (when I set it
up), it was awful... IDE speed was around 1-1.5 MB/s on the internal IDE bus
whereas SCSI was twice as fast with a really old Quantum LPS105...
> I remember a 68040 40 MHz had so little reserves im memory bandwidth
> and CPU power that even io buffered in RAM (not in disk buffer) had
> a maximum throughput of about 5.6 MB/s.
Well, when I would be able to reboot arrakis now, I could have a look at
that, but AFAIR memory bandwidth was much higher, something around 40
MB/s... (I usually tested this with bustest program on AmigaOS, see Aminet)
What could be is that memory bandwidth is limited under Linux due to some
restrains of memory protection and context switches or something like this,
which doesn't occur under AmigaOS...
--
Ciao... //
Ingo \X/
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