On 2010-Aug-17 22:29:46 +0200, Dimitry Andric <dimi...@andric.com> wrote: >On 2010-08-17 18:29, Alan Cox wrote: >> Try it again on a memory resident file with the MAP_PREFAULT_READ option >> that is provided by this patch: >> >> http://www.cs.rice.edu/~alc/MAP_PREFAULT_READ.patch > >A time trial gives: > > grep with normal mmap() 1396s > grep with prefault mmap() 1354s > grep with regular read() 1354s
Is this with uncached (ie remount the filesystem on each test) or cached data? Which filesystem (and does it change for different filesystems (particularly between UFS and ZFS))? And one trial is not statistically valid - especially given the small differences. How about multiple multiple trials with ministat. -- Peter Jeremy
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