App-services November 2020

app-services@lists.openampproject.org

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2020-10-27 OpenAMP App-services call recording, notes, slides, and action items (fwd)

by Stefano Stabellini

Hi Alex, Arnd, Jean-Philippe, and all, During the OpenAMP App-services call this week WindRiver gave a couple of extremely interesting presentations, see attached slides. Dan Milea discussed the usage of virtio between heterogeneous clusters, i.e. virtio frontends on the Cortex-R cluster and virtio backends on the Cortex-A cluster. They used a setup based on pre-shared memory to make it work, which I believe is similar to the swiotlb approach we discussed in Stratos. They noted that the last version of the virtio spec on github had something in regards to virtio and pre-shared memory regions that might help us cover this use-case from a spec perspective. Dan, would you be able to share a pointer to it for clarity? So far, we acted on the assumption that the virtio spec doesn't allow for this architecture today; it would be fantastic if it turns out that it already does. The other very interesting presentation by Joshua Pincus was about virtio-mmio and MSIs. They did excellent measurements on the performance of virtio-mmio and they found out that the single source of notifications (one interrupt) is the bottleneck. Adding MSIs vastly improved performance. You can see the detailed breakdown on slide #8 of "OpenAMP Virt I/O MMIO w/ MSI". This analysis really points in the direction of adding MSIs to virtio-mmio. Cheers, Stefano ---------- Forwarded message ---------- Date: Wed, 28 Oct 2020 18:41:09 +0000 From: Nathalie Chan King Choy via App-services <app-services(a)lists.openampproject.org> Reply-To: Nathalie Chan King Choy <nathalie(a)xilinx.com> To: "app-services(a)lists.openampproject.org" <app-services(a)lists.openampproject.org> Subject: [App-services] 2020-10-27 OpenAMP App-services call recording, notes, slides, and action items Hi all, The notes from yesterday’s OpenAMP App-services call can be found at: https://github.com/OpenAMP/open-amp/wiki/OpenAMP-Application-Services-Subgr… The link to the Webex recording is in the notes. I am not sure how long before the recordings expire or I will hit my storage limit, so if you need to catch up by watching the recording, please download it in the next couple weeks. Please find attached the slides from Dan & Josh. Action items: * Dan & Josh to send slides (DONE) * Stefano to start a thread w/ the folks who are working on shared memory & VirtIO Best regards, Nathalie C. Chan King Choy Program Manager focused on Open Source and Community -- App-services mailing list App-services(a)lists.openampproject.org https://lists.openampproject.org/mailman/listinfo/app-services

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App-services November 2020