The content of this blog is my personal opinion only. Although I am an employee - currently of Nvidia, in the past of other companies such as Iagination Technologies, MIPS, Intellectual Ventures, Intel, AMD, Motorola, and Gould - I reveal this only so that the reader may account for any possible bias I may have towards my employer's products. The statements I make here in no way represent my employer's position, nor am I authorized to speak on behalf of my employer. In fact, this posting may not even represent my personal opinion, since occasionally I play devil's advocate.

See http://docs.google.com/View?id=dcxddbtr_23cg5thdfj for photo credits.

Thursday, June 21, 2012

recursive make can break parallel make -j

Recursive make is dangerously stupid.  There are better tools, but not everyone has realized.

In a system using recursive make, two rules invoke recursive make for different rulesof the same directory.
Unfortunately, these rukes are not parallelizable.  The nonrecursive makefile knows this, but the separate recursive make invocations do not.

I.e. recursive make can break parallel make -j.

No comments: