Re: [Fwd: [linux-audio-dev] info point on linux hdr]

[Stephen C. Tweedie]

Hi,

On Mon, Apr 17, 2000 at 01:45:15PM -0400, Paul Barton-Davis wrote:
> >> 2) Why am I not having any of these problems ? Unlike Benno's code, I
> >>    Seagate 4.5GB Cheetah U2W 10K rpm              IBM 9GB UltraStar U2W 10K rpm
> >>    Quantum 4.5GB Viking U2W 7.5K rpm              3 x IBM 18GB UltraStar
> >
> >Ahh --- SCSI.  The request queuing for SCSI is very different to 
> >that for non-SCSI devices.  
> 
> Different enough that you feel its likely to explain the significant
> difference between my experience and that of both Benno and Juhana
> when trying to record to disk ?

Potentially, yes.

> Is it different enough to explain why
> the buffer cache write-behind batching doesn't seem to show up as a
> problem for me ?

Again, yes.  It's definitely worth trying the elevator fix.

> Stephen - thanks for paying attention and giving us time on this. I
> know you have a lot to work on, and that HDR is not what most people
> consider to be a hot Linux application;

No problem.  Actually, many of the problems you are encountering
have parallels in high-end server systems too.  This is definitely
an area where there is a lot of potential for interesting optimisations.

--Stephen