Re: [PATCH1/2] Use spawn() on Cygwin

[Norbert Thiebaud]

On Tue, Jul 30, 2013 at 10:39 AM, Eli Zaretskii <address@hidden> wrote:
>> From: Pavel Fedin <address@hidden>
>> Date: Tue, 30 Jul 2013 14:42:23 +0400
>>
>>  Please take this patch, Cygwin team told that they would like to integrate
>> with upstream. I have already posted it some time ago but got no reply.
>>  The patch significantly improves performance of Make under Cygwin.
>
> Thanks.
>
> Is there any discussion we could read about that with the details of
> the problem and how/why does the proposed patch solves it?

fork() is a very expensive operation in cygwin.
we are seeing that in LibreOffice build a lot.
I will try to pick up that patch and report numbers on it (we have a
pretty big make, with 125K+ targets
http://skyfromme.wordpress.com/2013/02/28/one/ )

>
> In general, I feel it's wrong to do this: Cygwin is a Posix platform,
> so it should be using the Posix code, to be as compatible with other
> Posix platforms as possible.  EMX is not a Posix platform, so using
> its code will likely make the Cygwin Make deviate from Posix behavior
> at times.

in theory you are right... in practice Cygwin maybe be posix, but it's
underlying OS is not and the emulation layer can be very costly.

Norbert