[OE-core] setscene and perl -- pathological case

[Martin Jansa]

On Thu, May 10, 2012 at 05:20:31PM -0500, Mark Hatle wrote:
> We've discovered that perl seems to be a pretty bad pathological case for setscene.
> 
> Easy way to see what I mean:
> 
> bitbake perl
> bitbake -c clean perl
> time bitbake perl
> 
> The system isn't doing anything but running the setscene elements to bring perl 
> from the sstate-cache into the sysroot and related directories.. but it takes a 
> very long time to do this:
> 
> real    3m7.430s
> user    0m36.316s
> sys     2m46.742s
> 
> That is on my 8 core w/ 12 GB of ram system..  (standard SATA disks)
> 
> Digging into this, I found that the majority of the time is spent in 
> meta/classes/sstate.bbclass: sstate_installpkg
> 
> If you look for the three os.system("sed ...  calls, almost all of the 3 minutes 
> is there.  Perl has so many text files with embedded paths that a significant 
> amount of time is spent preparing these files and fixing paths.
> 
> I did a test and changed the three sed cases into a single sed operation:
> 
> -            os.system("sed -i -e s:FIXMESTAGINGDIRTARGET:%s:g %s" % 
> (staging_target, sstateinst + file))
> -            os.system("sed -i -e s:FIXMESTAGINGDIRHOST:%s:g %s" % 
> (staging_host, sstateinst + file))
> -            os.system("sed -i -e s:FIXMESTAGINGDIR:%s:g %s" % (staging, 
> sstateinst + file))
> +            os.system("sed -i -e s:FIXMESTAGINGDIRTARGET:%s:g -e 
> s:FIXMESTAGINGDIRHOST:%s:g -e s:FIXMESTAGINGDIR:%s:g %s " % (staging_target, 
> staging_host, staging, sstateinst + file))
> 
> The result:
> 
> real    1m20.979s
> user    0m19.400s
> sys     1m4.115s
> 
> This is a very significant performance improvement.  I'm not sure if it's 
> possible to speed this up even more, but it would be nice if we could get things 
> under a minute.
> 
> Does anyone see a way we could do this quicker or in a better way to boost 
> performance?  (One possibility is figure out how to thread the file processing 
> and use available processors...)

I guess it does process for all files in fixmepath file, so try to run
sed on all of them (or chunks) together with xargs like in:
http://git.openembedded.org/openembedded-core/commit/meta/classes/sstate.bbclass?id=94c52d68fc2ce258bcc5b0978ac73413480a1a93

Cheers,
-- 
Martin 'JaMa' Jansa     jabber: Martin.Jansa at gmail.com
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