Bug 492386 - Found nondeterminism in Valgrind's BBV logs
Summary: Found nondeterminism in Valgrind's BBV logs
Status: REPORTED
Alias: None
Product: valgrind
Classification: Developer tools
Component: bbv (show other bugs)
Version: 3.18.1
Platform: Ubuntu Linux
: NOR normal
Target Milestone: ---
Assignee: Vince Weaver
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-08-30 03:33 UTC by jo.alen1@outlook.com
Modified: 2024-09-01 09:00 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
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. (311.30 KB, image/png)
2024-08-30 03:33 UTC, jo.alen1@outlook.com
Details

Note You need to log in before you can comment on or make changes to this bug.
Description jo.alen1@outlook.com 2024-08-30 03:33:01 UTC
Created attachment 173111 [details]
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.
Comment 1 Paul Floyd 2024-08-30 04:18:54 UTC
I don’t think anyone is maintaining BBV so don’t expect a quick response.
Comment 2 jo.alen1@outlook.com 2024-08-31 19:31:41 UTC
(In reply to Paul Floyd from comment #1)
> I don’t think anyone is maintaining BBV so don’t expect a quick response.

No worries! Anything helps from the Valgrind team!!