Official request: Please make GNU grep the default
Dimitry Andric
dimitry at andric.com
Wed Aug 18 21:12:33 UTC 2010
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. :)
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