Performance optimization in av::fixup - use buffered IO, not mapped file

Corinna Vinschen corinna-cygwin@cygwin.com
Wed Dec 12 17:28:00 GMT 2012


On Dec 12 18:15, Corinna Vinschen wrote:
> On Dec 12 12:11, Christopher Faylor wrote:
> > On Wed, Dec 12, 2012 at 12:06:08PM -0500, Ryan Johnson wrote:
> > >It's painfully reproducible. It takes nearly two hours for a gcc 
> > >bootstrap compiler to configure the various bits of the next stage. It's 
> > >the same for emacs unexec (as OP reported).
> > 
> > I'd like to see a small controlled test case which demonstrates the
> > problem.  If the claims here are all true then it should be very easy to
> > demonstrate without resorting to bootstrapping the compiler.
> > 
> > And, given my comment about setup.exe, I suspect that this isn't going
> > to be as alarming an issue for the normal Cygwin user as it is for
> > people who, e.g., rebuild their own compilers.
> 
> Which would speak for adding a "nosparse" mount option.

...or not.  The problem is not to add the mount option, but to make sure
people know that option and use it when "cygwin is slow".  This rather
speaks for making nosparse the default and "sparse" the option, I guess.


Corinna

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



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