Re: Cygwin Performance and stat()

[Reini Urban <rurban at x-ray dot at>]

Christopher Wingert schrieb:
> I assume POSIX compatibility.  However, I bet there are cases where one
> can sacrifice compatibility for performance (configurable with an
> environment flag of course).
>
> See
> http://marc.info/?l=git&m=122278284210941
> for an example.

This git do_stat is for only meant for a 50% implementation of relative 
paths known before, and therefore onyl useful to certain apps, but it 
can never be useful for the cygwin1.dll layer, because cygwin has to 
provide the POSIX compat. layer, and not 50% cut-throughs for apps which 
don't need the other 50%. ACL, mounts, symlinks, inode.

A better chaching stat or an cygwin extension for relative deeper only 
would be possible, but a better caching stat would need more memory and 
sacrifice speed for the first stat.
A fast relative stat is very unlikely to be #IFDEF's in some apps just 
for us. So it's more likely that those apps which might need it, come up 
with their own 50% less, but 50% faster bits, as git did.

> > On Sun, May 30, 2010 at 08:54:10AM -0700, Christopher Wingert wrote:
> > > I was looking into speeding up stat() performance.  More specifically
> > > bash, ls, test, stat performance.  I've seen the subject come up before.
> > > Git recently implemented a native Win32 work around.  Are there any
> > > cygwin
> > > patches around?
> >
> > If there was a way to make stat() faster why wouldn't it be in the source
> > code already?
--
Reini Urban
http://phpwiki.org/  http://murbreak.at/

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