Re: Warning - running *really* short on DMA buffers while doing file transfers

Matthew Jacob
2002-09-27T07:29:04Z

The issue here is not whether it's appropriate to oversaturate the
'standard' SCSI drive- it isn't- I never suggested it was.

I'd just suggest that it's asinine to criticise an HBA for running up to
reasonable limits when it's the non-toy OS that will do sensible I/O
scheduling. So point your gums elsewhere.

On Fri, 27 Sep 2002, Matthew Jacob wrote:

>
>
> On Fri, 27 Sep 2002, Jens Axboe wrote:
>
> > On Fri, Sep 27 2002, Matthew Jacob wrote:
> > > >
> > > > So I think the 'more tags the better!' belief is very much bogus, at
> > > > least for the common case.
> > >
> > > Well, that's one theory.
> >
> > Numbers talk, theory spinning walks
> >
> > Both Andrew and I did latency numbers for even small depths of tagging,
> > and the result was not pretty. Sure this is just your regular plaino
> > SCSI drives, however that's also what I care most about. People with
> > big-ass hardware tend to find a way to tweak them as well, I'd like the
> > typical systems to run fine out of the box though.
> >
>
> Fair enough.
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