On 2010-08-18 22:52, Peter Jeremy wrote: >> 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?
This is all on the same filesystem, and the test file is ~370MB, so eventually all data will be in RAM, most likely. E.g. normal mmap() seems to add a bit of overhead that explains the slower result. > Which filesystem (and does it change for different filesystems > (particularly between UFS and ZFS))? I only checked on UFS2. > And one trial is not statistically valid - especially given the small > differences. How about multiple multiple trials with ministat. The result were averages of three trials; they were fairly close to each other, but I didn't calculate the standard deviation. I was not aware of ministat, which looks like a real handy program. :) _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
