gem5 Developers' Monthly Meeting - July 10th 2025, 1600 UTC

[BobbyRBruce]

Meeting Link

https://teams.microsoft.com/l/meetup-join/19%3ameeting_ZTAxYmYzN2UtZWZiNC00MTQ5LWEyMDAtNjJlMzY2NWJlYzUx%40thread.v2/0?context=%7b%22Tid%22%3a%22a8046f64-66c0-4f00-9046-c8daf92ff62b%22%2c%22Oid%22%3a%223058c8c1-4bfd-455e-878e-43f1fa6ea2d1%22%7d

Meeting ID: 262 758 737 690
Passcode: Mo679wh2

[BobbyRBruce]

(meeting notes --- AI generated)

gem5 Developers Meeting Notes – July 20, 2025

Release Recap: gem5 25.0

• gem5 version 25.0 was released last month and is considered one of the most stable releases to date.
• The stability is attributed to more rigorous and sustained testing efforts during the release cycle.
• No major regressions or angry user feedback has been received.
• Developers were encouraged to continue testing and report issues, even post-release.

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Hotfixes for gem5 25.0

• A hotfix release (tentatively versioned 25.0.0.1) is in progress.

• Fixes currently planned for this hotfix include:

  • PR arch-vega: GPU TLB Multi Page Size Support #2436: A GPU-related issue (clarified to not have been pushed by Matt).
  • A fix for looppoint capabilities.
  • A soon-to-be-submitted fix from Giacomo, expected within a day of the meeting.

• Bobby emphasized a preference for bundling fixes into fewer hotfix releases to minimize overhead.

Hotfix Action Items

• 🔧 Merge PR arch-vega: GPU TLB Multi Page Size Support #2436.
• 🔧 Include the looppoint fix.
• ⏳ Receive and review Giacomo's hotfix submission.
• 📦 Publish 25.0.0.1 once these are merged.
• 🔁 Remain open to future hotfixes if necessary but aim for bundling.

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Workshop Recap: gem5 at ISCA (Jamf Live)

• The gem5 workshop at ISCA was successfully held.
• The event was well-attended and received positive feedback from participants.
• All talks were recorded and are now available on the gem5 YouTube channel.
• Slide decks are still being gathered from presenters.
• Several attendees agreed to write blog posts about their presentations for the gem5 website.

Workshop Action Items

• 📺 Promote video recordings.
• 📄 Finalize and upload slide decks.
• 📝 Coordinate and collect blog post writeups from presenters.

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Planning for gem5 25.1

Following the hotfix discussion, Bobby initiated planning for the next feature release: gem5 25.1.

• Community Solicitation:

  • Developers were asked to notify the team of any big-ticket items expected to land in the next 3–4 months.
  • The goal is to coordinate early and avoid surprise merges near release time.

• clang-format PR Discussion:

  • The PR authored by Richard is meant to introduce an agreed-upon style format tool for gem5 code.
  • It enables local auto-formatting using a shared configuration.
  • Concerns were raised about merge conflicts, rebase difficulties, and how formatting will interact with long-lived branches.
  • The team agreed that clarity around workflows will be essential for widespread adoption.

• Modularization Effort:

  • A major goal for 25.1 is to modularize the gem5 codebase, improving separation of components into better-defined libraries or layers.
  • This would benefit external tool developers, improve build system hygiene, and enhance testability.
  • No rigid architecture plan was presented in this meeting, but the effort was framed as a multi-month initiative.

25.1 Planning Action Items

• 🧱 Finalize and review the clang-format PR, clarify rebasing and workflow implications.
• 🧩 Begin implementation or at least architectural planning for modularization.
• 📬 Reach out to contributors for expected major PRs over the coming quarter.
• 📋 Draft initial 25.1 roadmap ahead of the next developer meeting.

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Meeting Scheduling

• Apologies were issued for the timing confusion of this month’s meeting.
• Starting in August, developer meetings will follow a rotating time schedule to improve accessibility for global contributors.
• The next meeting is expected to be late evening California time to accommodate East Asia.

Scheduling Action Items

• 🕒 Finalize and announce August meeting time.
• 📅 Implement and publicize monthly time rotation policy.

[BobbyRBruce]

Recording of the meeting: https://youtu.be/LFgGsnPahLE

Slides:
gem5-dev-meeting-20250710.pptx