On Fri, Jul 04, 2008 at 11:50:34AM -0400, Benji York wrote: > On Thu, Jul 3, 2008 at 5:22 PM, Benji York <[EMAIL PROTECTED]> wrote: > > I'm working on making the zope.testing test runner run tests in > > parallelized subprocesses. The option will likely be spelled -j N, > > where N is the maximum number of processes. > > The branch > (svn+ssh://svn.zope.org/repos/main/zope.testing/branches/benji-parallelize-subprocesses) > is feature complete. I basically did a very simple transformation that > resulted in the runner spawning subprocesses in threads, several at a > time, instead of spawning them serially. The patch is less than 250 > lines. Any critiques of the changes would be appreciated.
I'll try to take a look. > I found that to eliminate nearly all CPU idle time, I had to use -j4 on > my two core laptop. > > For a particular test corpus on a 4 core machine -j1 (the default) takes > about 7 minutes -j6 takes about 2 minutes 20 seconds. I tried this in a Zope 3.4 checkout I had handy on a Core 2 Duo machine (1.8 GHz, running 64-bit Ubuntu Hardy). One test module could not be loaded, which explains the slightly lower number of tests reported: Test-module import failures: Module: zope.app.twisted.ftp.tests.test_zopetrial Traceback (most recent call last): File "/home/mg/src/ivija-zope-3.4/Zope3.4/src/zope/app/twisted/ftp/tests/test_zopetrial.py", line 37, in ? orig_configure_logging = zope.testing.testrunner.configure_logging AttributeError: 'module' object has no attribute 'configure_logging' Here are the results: time # tests real user system reported old test runner 3m16.033s 2m44.670s 0m2.832s 6895 zope.testing trunk 2m27.816s 1m58.971s 0m2.196s 6890 new test runner -j0 2m37.322s 2m5.808s 0m2.944s 6890 new test runner -j1 2m32.249s 1m58.847s 0m2.652s 6890 new test runner -j2 2m22.287s 3m51.214s 0m13.457s 584 new test runner -j3 2m20.560s 3m46.990s 0m12.613s 584 new test runner -j4 2m30.026s 3m43.198s 0m13.241s 584 At the end of the experiment I discovered that I have CPU frequency scaling enabled. It only scales down to 1.6 GHz and quickly jumps back up to 1.87 GHz. I find the speedup by switching to a modern test runner somewhat unexpected. Can those 5 missing tests really account for 45 seconds? Zope 3 appears to be composed of a multitude of small tests. If my numbers are correct, the advantage of using both CPU cores is almost completely negated by the extra bookkeeping that the test runner has to do. Visual ogling of my CPU usage applet shows that -j0/1 use only one CPU, while -j2 and above use only one CPU for the first test layer (zope.app.apidoc.testing.APIDocLayer) and then use both CPUs for the rest. Bug? The total number of tests is misreported when you have -jN with N > 1. "Test-module import failures" is printed several times. test -j4 printed that message 37 times! test -j1 only did it once. -j2 and -j3 also did that a bit often (once per layer?) As far as I can understand, the granularity of the test distribution to CPUs is a test layer? If so, that's rather unfortunate for my application, which has only two layers (unit and functional). Especially given the quirk that the first test layer is run on one CPU while the other idles. Marius Gedminas P.S. Zope 3 is such a sweet little thing! All the tests finish in 3 minutes! Heaven. -- The planning fallacy is that people think they can plan, ha ha. -- Eliezer Yudkowsky, http://www.overcomingbias.com/2007/09/planning-fallac.html
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