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Windows: build with "build_pgo.bat -2" fails to optimize python.dll #61867
Description
| BPO | 17667 |
|---|---|
| Nosy | @loewis, @tjguk, @zware, @akruis |
| Files |
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 2019-09-10.13:01:34.261>
created_at = <Date 2013-04-08.18:10:34.607>
labels = ['build', 'OS-windows']
title = 'Windows: build with "build_pgo.bat -2" fails to optimize python.dll'
updated_at = <Date 2019-09-10.13:01:34.261>
user = 'https://github.com/akruis'bugs.python.org fields:
activity = <Date 2019-09-10.13:01:34.261>
actor = 'steve.dower'
assignee = 'none'
closed = True
closed_date = <Date 2019-09-10.13:01:34.261>
closer = 'steve.dower'
components = ['Build', 'Windows']
creation = <Date 2013-04-08.18:10:34.607>
creator = 'anselm.kruis'
dependencies = []
files = ['29739']
hgrepos = []
issue_num = 17667
keywords = ['patch']
message_count = 4.0
messages = ['186322', '223474', '229061', '229221']
nosy_count = 4.0
nosy_names = ['loewis', 'tim.golden', 'zach.ware', 'anselm.kruis']
pr_nums = []
priority = 'low'
resolution = 'out of date'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'compile error'
url = 'https://bugs.python.org/issue17667'
versions = ['Python 2.7']
Activity
akruis commentedon Apr 8, 2013
Version: 2.7.4 (and any prior 2.7-version. not tested with 3.x)
Compiler: VS 2008 Professional
If I compile Python using the batch
Visual Studio fails to correctly collect profile information for the project "python27.dll". As a result, no real optimisation takes place.
The command "build_pgo.bat -2" runs the full test suite (..\lib\test\regrtest.py) to collect profile data. Experiments show, that several test cases (i.e. test_os and test_subprocess) break the collection of profile data. Probably the failure is related to the creation of sub-processes. I consider it a Visual Studio bug.
To work around this issue I created a list of good test cases and patched build_pgo.bat to run only the tests from this list.
BreamoreBoy commentedon Jul 19, 2014
See also bpo-21907.
zware commentedon Oct 11, 2014
I think I'd rather see a blacklist than a whitelist; it should be much shorter and can be passed to regrtest with the "-x" option within build_pgo.bat.
Since we officially discourage PGO with VS 2008 and 2010 (due to compiler bugs) anyway, marking this as low priority.
akruis commentedon Oct 13, 2014
It's indeed a very low priority issue.
You mention VS2008 and VS2010 PGO compiler bugs. I'm aware of the VS 2010 bugs, but I didn't observe any VS 2008 PGO bug with Python 2.7. Are you aware of any publicly available bug reports?
About the black/white list. I started with a black list, but then I switched to a white list for the following reason: the goal of running the test suite is to generate a reasonable profile. It is not a goal to test anything. Therefore both white list and black listing is possible.
I consider it more likely that a newly added test breaks the PGO build than that an existing test will be modified in a breaking way. Therefore I consider the while list superior for this particular application.
But as you already stated, it is low prio.