https://bugs.kde.org/show_bug.cgi?id=492386
Bug ID: 492386
Summary: Found nondeterminism in Valgrind's BBV logs
Classification: Developer tools
Product: valgrind
Version: 3.18.1
Platform: Ubuntu
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: bbv
Assignee: vi...@csl.cornell.edu
Reporter: jo.al...@outlook.com
Target Milestone: ---
Created attachment 173111
--> https://bugs.kde.org/attachment.cgi?id=173111&action=edit
Red represents removals while green represents additions. This is a screenshot
of two Valgrind BBV logs for the same executable and configurations ran for two
runs.
Hi Valgrind Maintainers and Team!
I have been using Valgrind as a tool to check for nondeterministic behaviors
and I know that there are multiple subtools that Valgrind's suite comes with. I
would like to inquire about the BBV subtool in analyzing some of the reports
generated after each run against a binary. This nondeterminism concerns the
Valgrind-generated log as a result of running BBV on a binary. Our test
concluded that there was nondeterministic reporting in 37/41 repositories.
Would the team look into this matter and remedy the issue or provide a
potential explanation for this?
Thank you!!
STEPS TO REPRODUCE
1. Use a GitHub Actions runner with Ubuntu 22.04 + Valgrind 3.18.1 pulled from
the Ubuntu package manager
2. Run your executable with exp-bbv enabled.
3. Obtain the Valgrind reports
OBSERVED RESULT
Specifically, we noticed that the common category of these apparent flakiness
comes from Valgrind's performance metrics summaries (i.e - total instruction
counts and total/unique reps). The attached screenshot shows in red of missing
versus green of additions.
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