setscene and perl -- pathological case

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...)

--Mark

good job. in theory you could pythonise it even further using re module

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: [email protected]