Xen Maintainer, Committer and Developer Meeting/June 2012 Minutes
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Agenda:
- Call membership (new organisations to invite, +/- representatives from existing organisations, etc.
- Review outstanding ACTION items.
- Current technical challenges.
- Latency of physical interrupts to Hypervisor
- Coordination on current and future work, e.g. planned development activities for next release(s), roadmap items
- Xen 4.2 release status (Ian C)
- Xen 4.3 planning, time lines, what people are working on (Ian C)
- Community news, activities.
- XenSummit CFP deadline (Lars)
- Security process lessons learned (Ian C)
- Should we be more public about the meeting outcome (i.e. do we have public minutes somewhere) (Lars)
Attendance
- Chair: Ian Campbell (committer)
- Secretary: Lars Kurth
- Boris Ostrovsky, Ian Pratt (Xen.org chairman), Jan Beulich (committer), Jason Douglas, Jun Nakajama, Konrad Rzeszutek Wilk, Olaf Hering, Sheri Flores, Simon Rowe (standing in for James Bulpin)
- Others: excused this time
Technical challenges
Latency of physical interrupts to Hypervisor (Jun N)
- The interrupt path in Xen has a higher latency compared to vanilla Linux
- This is independent of PVOPS Kernel or classic Xen Kernel
- Order of magnitude is about 20-30 microseconds
- It appears that there is room for optimization and that we should have a discussion about this. Intel is planning to look into whether there is too much code on the codepath as part of debugging.
- Simon: IRQs & MSIs - Legacy has rather bad latency. Andy Cooper is currently investigating
- Konrad: PVOPS is not doing a fast ACK - an area of extra improvements for PVOPS (note: was fixed after meeting)
Coordination on current and future work
Xen 4.2 release status (Ian C)
- Release candidates should be starting in 2-3 weeks. No hypervisor blockers currently, only tools blockers
- Typically we get 6-9 RC's: this would give us a release date of August (close to XenSummit)
- We are in good enough shape to start cleaning up the feature list of http://wiki.xen.org/wiki/Xen_4.2 - Lars start doing this
- We all agreed that the release cycle was too long
- Generally the consensus was that the 4.2 release cycle was too long. This happened due to lack of ownership.
- The consensus was that we need a discussion on how to do this better: should have a discussion with agreements at the dev meeting before XenSummit. The Linux model was briefly raised but doesn't sound right. Ideally we’d have 9 month release cadence (maybe less). We probably need to be more formal about this and have owners for a release (as well as maintenance releases). We will need volunteers though: Jan and George volunteered
- Jan: Maintenance releases should follow a fixed heartbeat of 3 months. Have not quite achieved this: we had no predictable cadence
Xen 4.3 planning, time lines, what people are working on (Ian C)
- George Dunlap volunteered to act as "release manager/owner" for Xen 4.3
- Lars to schedule a session at the Dev meeting at XenSummit
- George will start reaching out to collect bigger TODO items after RC's and start planning
Community news, activities
XenSummit CFP deadline (Lars)
Reminder: XenSummit CFP ends on June 15th, see http://xen.org/community/xensummit.html Lars secured space for invite owner Developer meeting before XenSummit. Send out instructions and communicate.
Security process lessons learned (Ian C)
- Ian reminded everybody that the lessons learned for the security process will start the week of June 18th. See http://lists.xen.org/archives/html/xen-devel/2012-06/msg00675.html
Should we be more public about the meeting outcome
- Need to balance open and frank discussion amongst the group vs. need for transparency
- Lars put the following motion to a vote:
- Send meeting notes to the group first **Group is allowed to request for areas not to be published publicly (as to not stifle important discussion)
- Result of vote: motion agreed
ACTION items
Owner | Description | Status |
---|---|---|
Simon | Discuss IRQ's and MSIs with MSIs and get Andy Cooper talking to Jun on xen-devel | |
Lars | Start cleaning up Xen 4.2 feature list such that it is in good shape when we go into Xen 4.2 RC's | |
Ian | Ping Keir re maintenance releases. The last RC's of maintenance releases is a few weeks old. | Done, RC2's published 18/6 |
Lars | Schedule discussion on Xen Release and Maintenance cycle for Xen Dev Meeting at XenSummit | Done, see (1) |
Konrad | How do we evolve blkback? Raise on xen-devel and set up a meeting on how to approach this problem | |
Lars | Communicate info re dev meeting at XenSummit and put together invite list | Done, see [1] |
Don | Future X32 work: Don to make a more detailed proposal on the mailing list. Also need to engage distros to gage impact. | |
Konrad | Performance tooling: Konrad to summarize what is available on xen-devel. Lars to summarize on wiki. | Done, see [2] & Xen Profiling: oprofile and perf |