[mythtv-users] Must make recent myth trunk with "-j 1"

Michael T. Dean mtdean at thirdcontact.com
Mon Feb 2 17:47:16 UTC 2009

On 02/02/2009 03:20 AM, Allan Stirling wrote:
> James Purl wrote:
>> Good evening/night.
>> I am sending this to -users first as a "any one else getting this" 
>> and not troubling the devs (as I don't have all the exact error message).

Thank you.

>>   I custom compile myth SVN trunk using some home-grown debian 
>> packaging (ie the "debian" directory) for mythbuntu. I do all the 
>> package creation on a Core i7 system.  I have done probably 8-10 
>> weekly-ish builds of myth svn, but sometime between r19816 and 
>> r19900, something in  the Myth source causes the build to fail if I 
>> use "too many" CPUs.  My build process uses the "-j" option with the 
>> make command, and this used to work (and fly) on the i7.  As of some 
>> version > 19816 and <=19900, something in the libavcodec area causes 
>> the parallel build to fail.  I was wondering if anyone more in the 
>> know might know what changes I would need to make to my source to 
>> enable parallel builds?  I've since just changed my process to do the 
>> make with "-j 1" in the meantime, which works fine (albeit much slower).
>> I apologize in advance for lack of information (exact error message, 
>> etc.), but I put this out there in case it is a lightbulb moment for 
>> someone... Next time I do a build I'll try to get the exact point 
>> that compilation stops.  Oh yeah, if I just issue another make after 
>> it stops, compilation completes, so I presume its a matter of needing 
>> a makefile dependency so that filex.so or filex.a exists before it is 
>> needed by source filey.cpp.
> You need a lot of memory to compile Myth. I've seen gcc take over 
> 1.5Gb on some files. If you hit the wrong combination, this could mean 
> over 3Gb used. Post the error message and check your dmesg for an OOM 
> condition. 

And, yes, there are reports of "-j x" where x > 1 failing to work 
properly recently, so, just use "-j 1" until using "-j 2" or "-j 4" 
works for you.  :)  (I.e. when you see the commit that says something 
about fixing multiple-job compilation or whatever, then try increasing 
x, again.)


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