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


On Oct  6 14:37, Yoni Londner wrote:
> The difference in huge. while opening the file with GENERIC_READ
> took almost 1ms per file, opening with FILE_READ_ATTRIBUTES only
> took 0.027ms per file:
> testing /bin QIFR 3588 files stat() 3312ms, per file: 0.9229ms
> testing /bin QIF 3588 files stat() 97.66ms, per file: 0.02722ms

I can't reproduce any noticable difference:

  0.2093ms  <= QIF  <= 0.3153ms
  0.2112ms  <= QIFR <= 0.3306ms

> I will start working on a patch doing this, and hope to post it soon.

Did anybody of you notice the license problem which has been mentioned at
leats three times now?  Please read http://cygwin.com/contrib.html.

If it's really as easy as dropping the GENERIC_READ, then I can do that
in symlink_info::check easily.  That's basically what is different
between 1.7.5 and 1.7.7.  "It seemed to be a good idea at the time".

> Currently we have nothing to do with the driver, but maybe in the
> future we will find better ways to improve performance, that will
> require a kernel driver.

I'd prefer to stick to user space.


Corinna

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


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