[M3devel] possible cygwin createprocess/fork cost measurements..

[Olaf Wagner]

Quoting Jay <jayk123 at hotmail.com>:

>  spawn(nowait) + waitpid is about the same as spawn(wait), and is   
> close to system() in inflexibility, but system() has an implicit   
> shell wrapper and so is slow.

To eliminate the shell wrapper you could use System.ExecuteList
from package sysutils in M3 and

   q_exec( cmd ) --> int (since CM3 d5.6.0)

in quake (see quake manual on WWW), or does any Process.Create
on Windows invoke a shell on NT386GNU? I wouldn't think so
(but haven't checked).

> It seems that spawn is faster than CreateProcess at running .exes   
> that use cygwin1.dll. That is a little odd. It must be something to   
> do with the child startup code talking to its parent or something   
> and doing so more efficiently when the immediate parent uses Cygwin.  
>  I might dig into that. Like, a dynamic choice between CreateProcess  
>  and spawn could be more efficient, but so far I'm not sure even   
> using CreateProcess here is "easy enough".
>
> Is there anywhere in the cm3 tree appropriate to checkin such   
> experimental code?
> I can put it in my private svn...

Yes, just create a branch:

   cvs tag -b devel_process_perf_opt m3core ...
   cvs up -r devel_process_perf_opt m3core ...

and you are then working on the branch, until you issue

   cvs up -A m3core ...

Hope this helps,

Olaf
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