Re: [resent PATCH] Re: very slow parallel read performance

Oliver Neukum
2001-08-27T20:09:30Z

Am Montag, 27. August 2001 21:55 schrieb Richard Gooch:
> Daniel Phillips writes:
> > The quesion is, how do you know you're streaming? Some files are
> > read/written many times and some files are accessed randomly. I'm
> > trying to avoid penalizing these admittedly rarer, but still
> > important cases.
>
> I wonder if we're trying to do the impossible: an algorithm that works
> great for very different workloads, without hints from the process.

For streaming we should be able to detect consecutive reads.
If it's not that easy could we not measure hit/miss ratios ?

> Shouldn't we encourage use of madvise(2) more? And if needed, add
> O_DROPBEHIND and similar flags for open(2).

For symmetry rather fadvise. Besides usage patterns may change.

Regards
Oliver