Messages in this thread | | | From | Keith Owens <> | Subject | Re: [Lse-tech] 7.52 second kernel compile | Date | Sun, 17 Mar 2002 12:45:03 +1100 |
| |
On Sat, 16 Mar 2002 09:37:00 -0800, "Martin J. Bligh" <Martin.Bligh@us.ibm.com> wrote: >Are you still doing something like this? ># MAKE="make -j14" /usr/bin/time make -j14 bzImage > >I tried setting the MAKE variable as well as doing the -j, >but it actually made kernel compile time slower - what difference >does it make on your machine? Can somebody clarify what this >actually does, as opposed to the -j on the command line?
It depends on which version of make you are using. make 3.78 onwards has a built in job scheduler which shares the value of -j across its children, yea unto the nth generation. Earlier versions of make did a simplistic 'run -j copies of make at the top level' and did not propagate -j to the lower levels.
With the recursive makefiles and make < 3.78 you need MAKE="make -j" to get a decent speedup because of the lack of choices at the top level Makefile. With make >= 3.79 you do not need MAKE="make -j14", it can interfere with make's own scheduler. See also make -l LOAD.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |