Cygwin Filesystem Performance degradation 1.7.5 vs 1.7.7, and methods for improving performance

Corinna Vinschen corinna-cygwin@cygwin.com
Thu Oct 7 13:25:00 GMT 2010


On Oct  7 15:17, Yoni Londner wrote:
> Hi,
> 
> Sorry for my prev email (I noticed your 2 emails only after I sent
> it) and for top posting.

No worries.

> > Actually, I can't reproduce it at all.  I just created a patch which
> > drops the GENERIC_READ and only opens the symlinks with it, just as
> > proposed.  The results between the two versions are statistically
> > identical.
> 
> I did a little investigation to find out why you can't reproduce it.
> I found that the cause it is so slow on my computer is NOD32 AV (as
> all the computers in my company).
> When i disable it, I got the results you got.
> 
> So, I looked for computers with different AV software and found two,
> one with Symantec, and one with Mcafee.
> Symantec was even slower:
>   3592 files stat() 4023ms, per file: 1.1201ms
> Mcafee more or less was the same:
>   3592 files stat() 3425ms, per file: 0.9535ms
> My computer (NOD32):
>   3592 files stat() 3353ms, per file: 0.9333ms

So, there's a good reason I hate virus scanners.  I'll check in my
patch then since it seems to be a good idea for all users which are
forced to use them.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat



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