pybench prep_times calculation error

[termim]

BPO	11895
Nosy	@malemburg, @jcea, @termim, @sandrotosi
Files	pybench.patch: divide prep_times by CALIBRATION_LOOPS

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2011-06-26.13:30:27.298>
created_at = <Date 2011-04-21.03:20:12.482>
labels = ['expert-installation', 'type-crash']
title = 'pybench prep_times calculation error'
updated_at = <Date 2011-06-26.13:30:27.297>
user = 'https://github.com/termim'

bugs.python.org fields:

activity = <Date 2011-06-26.13:30:27.297>
actor = 'sandro.tosi'
assignee = 'none'
closed = True
closed_date = <Date 2011-06-26.13:30:27.298>
closer = 'sandro.tosi'
components = ['Demos and Tools', 'Installation']
creation = <Date 2011-04-21.03:20:12.482>
creator = 'termim'
dependencies = []
files = ['21745']
hgrepos = []
issue_num = 11895
keywords = ['patch']
message_count = 3.0
messages = ['134192', '134204', '134366']
nosy_count = 5.0
nosy_names = ['lemburg', 'jcea', 'termim', 'sandro.tosi', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'accepted'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue11895'
versions = ['Python 3.2']

[termim]

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.

[malemburg]

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.

[python-dev]

New changeset e4fcfb8066ff by Jesus Cea in branch '2.7':
pybench prep_times calculation error (closes bpo-11895)
http://hg.python.org/cpython/rev/e4fcfb8066ff

New changeset 7569870a8236 by Jesus Cea in branch '3.1':
pybench prep_times calculation error (closes bpo-11895)
http://hg.python.org/cpython/rev/7569870a8236

New changeset 66ef5e844e6c by Jesus Cea in branch '3.2':
pybench prep_times calculation error (closes bpo-11895)
http://hg.python.org/cpython/rev/66ef5e844e6c

New changeset 8a277949d904 by Jesus Cea in branch 'default':
pybench prep_times calculation error (closes bpo-11895)
http://hg.python.org/cpython/rev/8a277949d904