Messages in this thread | | | From | Eric.Schenk@dna ... | Subject | Re: mmap/write vs read/write supprise | Date | Fri, 11 Jul 1997 15:26:28 +0200 |
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mcculley@iag.net <mcculley@iag.net> writes: >If we had madvise, the responsibility for determining the access >pattern could be put on the application. We could still use a better >default access pattern for mmap'd pages, though. Is the VM code >sophisticated enough yet to take advantage of an madvise syscall?
Another approach to this would be to use a predictive algorithm to determine which pages to prefetch. There was a neat article on doing this in JACM recently. The idea is to use the core of a good compression algorithm as the predictor. Apparently this can be proved to be within a constant of the optimal prefect strategy (i.e. the one that knows all future fetches in advance). I don't know off hand what the real performance of this would be like for kernel VM, but someone ambitious with a lot of time on their hands may want to play :)
-- Eric Schenk www: http://www.dna.lth.se/~erics Dept. of Comp. Sci., Lund University email: Eric.Schenk@dna.lth.se Box 118, S-221 00 LUND, Sweden fax: +46-46 13 10 21 ph: +46-46 222 96 38
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