Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes:
> I've found that "make -j64 test" does fairly well, bringing the cost down
> to something reasonable. Some of the SVN tests seem to sometimes randomly
> fail when done in parallel (I've not tried to debug it, I assume it's
> either some SVN bug, or just the test infrastructure having some shared
> SVN central repo thing), but it happens rarely enough that even if you
> have to run it twice, it's still worth it.
>
> [ Side note: the success output of "make test" makes it almost impossible
> to debug the error cases when you do that "make -j64" thing. Sad. It
> would be good to have the tests that fail clearly say exactly what test
> failed, because when you run 64 tests at the same time, having "case 9"
> fail is almost totally useless information - test 9 of _which_
> testsuite? ]
>
> I don't generally build docs, but they should run in parallel too, and at
> least your fedora build on kernel.org has a nice quad-core machine with
> lots of memory, so "-j8" or something is reasonable.
Thanks; unfortunately I already do all the tricks known to me, including
running make in parallel (I happen to use -j4) and maintaining a separate
build farm for each of the branches to avoid recompilation of programs and
reformatting docs. However, on a
model name : AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
stepping : 1
cpu MHz : 2004.185
cache size : 512 KB
with slow IDE disks, optimizing and cheating at the software level goes
only so far... For example, a typical cycle I just did looks like this:
$ /usr/bin/time Meta/Dothem --pedantic >:all.log 2>&1; tail -n 2 :all.log
2089.15user 1610.16system 45:56.91elapsed 134%CPU (0avgtext+0avgdata 0maxresident)k
220088inputs+3723296outputs (696major+305868883minor)pagefaults 0swaps
You have to remember that people use boxes that are a bit slower compared
to the boxes you are used to ;-)
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