On Tue, Nov 05, 2013 at 12:18:05AM +0000, Jasen Betts wrote:
> On 2013-11-01, Ian Eiloart <iane@???> wrote:
>
> > On my machines, `ls /var/spool/exim/input |wc -l` is about an order
> > of magnitude faster than `exiqgrep -c`.
> >
>
> on my machines `exim -bpc` is faster by a factor of approximately 3
Measurements are extremely sensitive to file-system cache effects.
Which ever measurement you run first (ls, or a custom queue scanning
tool) will generally be slower than the one you run right after
with all the directory inodes and blocks in core.
The other thing to keep in mind is that avoding a stat of every
file is a major savings. On many systems find(1) will not stat
files in directories with a link-count of 2 when the find pattern
does not depend on file metadata.
So generally you can't beat "find /path -name '<glob>' -print",
everything else is as slow or slower. But order of execution
matters, and measurements must be taken well spaced in time.
--
Viktor.
