abel deuring wrote:
>
> Oliver Rauch wrote:
>
> > > Well, I think that the sanei_scsi_req_enter / sanei_scsi_req_wait
> > > mechanism should give similar results as command repeating, but the
> > > former is more flexible, because you can also sent some status inquiries
> > > or whatever between to "read data" commands.
> > >
> >
> > Any ideas how we can test if sanei_scsI-req_enter is as fast as multiple reads in
> > the kernel?
>
> Difficult question; I don't know, if or how it is possible to issue
> multiple reads for the Linux kernel. But my guess is, that those
> multiple reads would have to be queued just like several SCSI commands
> being sent via sanei_scsi_req_enter and a write to the SG device file.
> (Douglas, any comments?)
Queuing up commands to a scanner that doesn't support tagged queuing
will cause those commands to be queued in the SCSI adapter driver
(or its silicon). In this case the only benefit to doing this is
lower latency for sending out the following command. Testing which
technique is better (other than the gross metric of scan time)
is a bit difficult.
Doug Gilbert
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