[parisc-linux] Re: tag starvation

[Richard Hirst]

On Fri, Jan 25, 2002 at 10:28:33PM -0700, Grant Grundler wrote:
> Ah ok...does "starvation" properly described by the following scenario?
> 
> While the drive is completing IO requests as fast as it can,
> *some* IO's don't complete because they never become the most
> optimal one to complete. This is an inherent "unfairness"
> in the normal SCSI  Queue tag. (Two other types of tags exist but
> are never used by Unix OS's AFAICT: ordered, Head)

Yes, that sums it up nicely.

> hmmm...could we just replace the following constant with
> a MODULE_PARAM() variable?
> 
> 53c700.h:#define NCR_700_MAX_TAGS               16

That sounds like a good idea; I think James was planning to add some
options like that to the driver, so we should check with him before
doing anything.

Richard