Mail Archives: cygwin/2001/11/13/13:15:32
On Tue, Nov 13, 2001 at 12:48:24PM +0100, Ralf Habacker wrote:
>>
>> Seen on the XEmacs list:
>>
>> > In general the cygwin build is slower, I think this is for 3 main
>> > reasons:
>> >
>> > 1) gcc optimization is not as good as MSVC
>> > 2) The cygwin portability layer adds a lot of overhead especially
>> > wrt file handling.
>> > 3) The cygwin implementation of fork-and-exec doesn't jive well with
>> > the VM size of xemacs. Supposedly a real vfork is in the works for
>> > cygwin but I can't attest to its functionality.
>>
>> Does #3 make any sense? I thought we *had* a real vfork...perhaps it
>> doesn't work well with large apps?
>>
>Can you explain this a little bit more ? I'm asking because in
>http://sources.redhat.com/ml/cygwin-xfree/2001-q4/msg00276.html I have described
>some problems with kde2 on cygwin relating performance and I'm very interested
>in getting more informations how to fix these problems. In short, loading the
>full kde2 desktop needs about 4 minutes and the reaction time for starting apps
>are > 1 minute. This seems to be unusable.
>My assumption are that these problems depends on application loading (vfork is
>used on every app), file and socket io.
You can't make an assumption like this. It's possible that there is
something in your app which is short-circuiting cygwin's vfork. There
are some pathological cases in which it will give up and revert to fork.
It's unlikely that gcc's optimization is so very bad that you'd see orders
of magnitude slowdowns. So, something else is going on. You'd have to
debug the application to figure out what that is.
cgf
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