Re: Official request: Please make GNU grep the default

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. :)