Attendees
- Mike
- Arnd
- Massami
- Shashi
- Alex
- Bill
- Mathieu
- Matt (Arm)
- Stefano (Xilinx)
- Mark
- Joakim
- Jean-Phillip
- Illias
- Bill
- Randy
- Sumit
- Bogdan (NXP)
- Srivatsa (QC)
- Ruchika
- Souvick
- Diana (NXP)
- Ed Doxat (Arm)
- Pratik
- Vincent
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Update on the demo progress
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Please ping Joakim if you have questions
Some resourses
Kevin Brodsky's talk giving answers to many of Arnd's questions statements
- https://youtu.be/CFweo8YFevg?t=7214
- https://www.linuxplumbersconf.org/event/7/contributions/654/
The current state of VirtIO-MMU / Limited Memory Sharing
Slides: Widget Connector url https://docs.google.com/presentation/d/1uwP8iPFaPivS-5QU_0ZnuhUHgFCKjdTvJ-H9uygJOUQ/edit#slide=id.p
Arnd: discussed 3 different approaches - do they all suck? Which to start prototyping?
Option 1: host manages shared memory, use swiotlb to force use of shared memory
Option 2: guest uses IOMMU, signals pages meant for access, no copying, expensive transactions updating iommu?
Option 3: new virtquue design, shared memory part of queue (inline).
Steffano: can we increase the size of the queue? Arnd: it involves changing the binary layout of the queue
Steffano: had to increase ring size for 9pfs implementation - needed to go to 2Mb (up from 512K)
Arnd: having large queues risks cache thrashing.
Alex: Does swiotlb always imply copying Arnd: yes
Stefano: what about virtio managing page allocation?
Alex: sees the complexities with existing devices, talked about video - size it for "known" memory bandwidth
Stefano: what about expanding option 3 but allowing bigger sizes queus appropriate to the device?
Arnd: Option 3 has s simplicity, but offers a allocation per device.
Srivista: our implementation currently is closer to option 1
Arnd: so which option to implement, or do we see if QC can share their implementation
Alex: I'm leaning towards 3 which could then be expanded to larger queue sizes for given devices. We could then compare with QC swiotlb approach
What is the development platform ?
Action items