Re: Preempt? (was Re: Cannot enable DMA on SATA drive (SCSI-libsata,VIA SATA))

[Nick Piggin]

Jeff Garzik wrote:
> Andrea Arcangeli wrote:
>
> > So I disagree with your claim that preempt risks to hide inefficient
> > code, there are many other (probably easier) ways to detect inefficient
> > code than to check the latencies.
>
>
>
> You're ignoring the argument :)
>
> If users and developers are presented with the _impression_ that long 
> latency code paths don't exist, then nobody is motivated to profile them 
> (with any tool), much less fix them.

But even without preempt you'd still have to profile the latency.

If anyone with !preempt notices unacceptable latency, then they can
report and/or profile and fix it. If not, then !preempt latency must
be acceptable.
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