Message 134204 - Python tracker

Message134204

Author	lemburg
Recipients	lemburg, termim
Date	2011-04-21.09:30:22
SpamBayes Score	1.4824025e-10
Marked as misclassified	No
Message-id	<4DAFF92A.7090106@egenix.com>
In-reply-to	<1303356013.22.0.66518331753.issue11895@psf.upfronthosting.co.za>

Content
Mikhail Terekhov wrote: > > New submission from Mikhail Terekhov <termim@gmail.com>: > > For some time now my builds of python 3.2 on x86_64 platform in SuSE OBS are failing depending on the phase of the moon. The spec file for the python3-base package uses 'make profile-opt' command to build and Makefile.pre.in uses pybench.py for profile guided optimization. The pybench.py fails sometimes with the '* Internal Error (use --debug to display the traceback)' error. Adding --debug gives 'calibration setup did not work' i.e. some of the self.overhead_times values in the Test.calibrate_test method became negative. It happens for the NestedForLoops test. The source inspection shows that most probably it was forgotten to divide by CALIBRATION_LOOPS when calculating prep_times. The patch against current head is attached, it solves the problem. Good catch. Your analysis is correct. Interesting that it took more than 6 years to discover this bug... looks like CPUs got more than 20 times faster since back then.

Content

Mikhail Terekhov wrote:
> 
> New submission from Mikhail Terekhov <termim@gmail.com>:
> 
> For some time now my builds of python 3.2 on x86_64 platform in SuSE OBS are failing depending on the phase of the moon. The spec file for the python3-base package uses 'make profile-opt' command to build and Makefile.pre.in uses pybench.py for profile guided optimization. The pybench.py fails sometimes with the '* Internal Error (use --debug to display the traceback)' error. Adding --debug gives 'calibration setup did not work' i.e. some of the self.overhead_times values in the Test.calibrate_test method became negative. It happens for the  NestedForLoops test. The source inspection shows that most probably it was forgotten to divide by CALIBRATION_LOOPS when calculating prep_times. The patch against current head is attached, it solves the problem.

Good catch. Your analysis is correct.

Interesting that it took more than
6 years to discover this bug... looks like CPUs got more than
20 times faster since back then.

History
Date	User	Action	Args
2011-04-21 09:30:25	lemburg	set	recipients: + lemburg, termim
2011-04-21 09:30:22	lemburg	link	issue11895 messages
2011-04-21 09:30:22	lemburg	create