[PATCH] Cygwin: Speed up mkimport

Brian Inglis Brian.Inglis@SystematicSw.ab.ca
Sat Nov 28 02:33:32 GMT 2020

On 2020-11-27 11:37, Achim Gratz wrote:
> Mark Geisert writes:
>> Still faster than two system commands :-).  But thanks for the
>> comment;
> It still seems you are barking up the wrong tree.
>> I thought I was merely grouping args, to get around Perl's
>> greedy arg list building for the system command.
> Wot?  It just takes a list which you can build any which way you desire.
> The other option is to give it the full command line in a string, which
> does work for this script (but not on Windows).  If it finds shell
> metacharacters in the arguments it'll run a shell, otherwise the forked
> perl just does an execve.
> If it's really the forking that is causing the slowdown, why not do
> either of those things:
> a) Generate a complete shell script and fork once to run that.
> b) Open up two pipes to an "xargs -P $ncpu/2 L 1 …" and feed in the file
> names.
> Getting the error codes back to the script and handling the error is
> left as an exercise for the reader.

Use explicit binary paths to avoid path search overhead; for portability: /bin/ 
for base system, dir, file, and net utils including compressors, grep, and sed; 
/usr/bin/ otherwise; {/usr,}/sbin/ for some admin utils not elsewhere.

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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