Re: cygwin performance

[Igor Pechtchanski <pechtcha at cs dot nyu dot edu>]

On Tue, 21 Oct 2003, Linda W. wrote:

> Has anyone done any testing on performance of cygwin utils over their
> native win counterparts?  The one that bothers me the most is the
> performance of cygwin "Find" and the windows 'find'.  If I'm just
> looking for filenames (find /c/ -name \*.wav) vs. looking for *.wav in
> windows find GUI, the performance difference is very large (maybe
> 8-10x?).  Is this unavoidable because the way cygwin does emulation or
> can optimizations be performed that would benefit all programs (not just
> find).

I suspect you're not comparing apples to apples here.  Later Windows
versions run a file indexing service in the background, which makes
finding files faster.  You might get more relevant results if you tried
using "locate"  after an "updatedb".

> Even using 'perl' over combo's of cat|tr|sed|grep|more is significantly
> faster to almost make the old unix standard scripting commands near
> worthless (I've gotten more efficient at 1-line perl scripts ala (perl
> -e '....').

You can always run these things under strace to see where the time goes.
Many factors enter into these slowdowns, e.g., if your Cygwin is installed
on a network drive, spawning multiple programs is likely to be much slower
than spawning one, no matter how large.

> Perhaps it is unavoidable, but I see things like find doing 2 'opens' /
> file when it is searching for files...can't it just do a 'stat' of some
> nature?  does it need to do an open, let alone 2?

Which tool do you use see this?  FWIW, I see at least one ReadFile in the
Cygwin fstat implementation (fstat_helper in fhandler_disk_file.cc), for
reading magic numbers to determine the executable bit.

> Just wondering....
> tnx,
> -linda

As always, PTC.
	Igor
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