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

[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.

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

The application knows how it's going to use data/memory. It should
tell the kernel so the kernel can choose the best algorithm.

				Regards,

					Richard....
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