Does cygwin slow things down?

Does cygwin slow things down?

[David E Euresti]

Has anybody done any tests to see just how fast cygwin is?
Like how do networking applications behave and the like?
I just ported a pretty large project and I've been noticing that it's much
slower, and I was wondering if it was cygwin that did it.
So anybody compiled something like apache who can tell me if it runs much
slower?

Thanks,
David


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Re: Does cygwin slow things down

[Michael Hoffman]

On Fri, 26 Jul 2002, David E Euresti wrote:

> Has anybody done any tests to see just how fast cygwin is?

Read the archives.

> I just ported a pretty large project and I've been noticing that it's much
> slower, and I was wondering if it was cygwin that did it.

Yes, Cygwin did it. Let's try and convict it for meanness, put it in
jail and throw away the key.

Seriously though, nothing is free. The extra layer of portability Cygwin
provides costs something in performance even if it is gratis. Some
suggestions for speedups despite this:

* I find automated virus checkers slow Cygwin's performance a lot

* make your PATH as short as possible

* make sure it doesn't include network shares or double slashes at the
beginning which will cause it to try to access a network share

* use mount --executable to speed up checking for executables

> So anybody compiled something like apache who can tell me if it runs much
> slower?

It's available on Setup; try it yourself.
-- 
Michael Hoffman <grouse@mail.utexas.edu>
The University of Texas at Austin


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RE: Does cygwin slow things down?

[Gary R. Van Sickle]

> Has anybody done any tests to see just how fast cygwin is?
> Like how do networking applications behave and the like?

Sporadically people have posted some numbers.  Somebody a while back had some
pretty detailed ones about forking and network stuff compared to Linux IIRC.
Somebody, perhaps someone much like myself only not as lazy, should set up some
sort of automated script and get some gnuplots going showing Cygwin's
performance as a function of time.  But then people in hell want icewater too.

> I just ported a pretty large project and I've been noticing that it's much
> slower, and I was wondering if it was cygwin that did it.
> So anybody compiled something like apache who can tell me if it runs much
> slower?
>

Slower than... not running at all?  I don't follow.

--
Gary R. Van Sickle
Brewer.  Patriot.


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RE: Does cygwin slow things down?

[David E Euresti]

Actually I believe I have found my bottleneck, select.

Each select call in win32 takes 13usecs, while a select call in Cygwin
takes 970usecs.  Now I know that there's some extra magic inside select to
make it work with pipes and files and stuff, but I just thought I'd
mention that that was the problem I'm having.  What I plan to do is before
calling select check to see if they are all sockets, if they are I'll just
extract the handles and call win32 select, I'll see what happens when I
do that.

On Fri, 26 Jul 2002, Dennis McCunney wrote:

> > -----Original Message-----
> > From: cygwin-owner@cygwin.com
> > [mailto:cygwin-owner@cygwin.com]On Behalf
> > Of David E Euresti
> > Sent: Friday, July 26, 2002 9:57 AM
> > To: cygwin@cygwin.com
> > Subject: Does cygwin slow things down?
> >
> > Has anybody done any tests to see just how fast cygwin is?
> > Like how do networking applications behave and the like?
> > I just ported a pretty large project and I've been noticing
> > that it's much
> > slower, and I was wondering if it was cygwin that did it.
> > So anybody compiled something like apache who can tell me if
> > it runs much
> > slower?
>
> Do a search of the mailing list archives.  This topic has gotten a _lot_ of
> discussion.
>
> Bottom line: Cygwin _is_ slower than a native Unix/Linux app, sometimes by
> an order of magnitude.  This is expected and unavoidable.  After all, Cygwin
> is an emulator, inserting a POSIX compatibility layer between apps compiled
> using it and the underlying Win32 OS.  Some POSIX calls simply don't have a
> clean mapping to Win32 calls, and there will always be overhead in
> emulation.
>
> If you profile your code, you can probably tell where the slowdown is
> occuring.  You may be able to change your code to run faster.  You may also
> identify areas where Cygwin could do things better. Patches are always
> gratefully accepted.
>
> > Thanks,
> > David
> ______
> Dennis
>
>


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