Re: [libvirt] [PATCH v3 1/2] Fix nodeinfo output on PPC64 KVM hosts

On Mon, 2015-07-06 at 17:34 +0530, Shivaprasad bhat wrote: Hi Shivaprasad, while reworking the series to address Martin's comments, I have created a couple more test cases and I've run into a situation I'm not sure how to handle. Suppose we have the following situation on the host: 0* 1 2 3 4 5 6 7 8* 9 10 11 12 13 14 15 16* 17* 18* 19* 20 21 22 23 24* 25 26 27 28 29 30 31 32* 33 34 35 36 37 38 39 40* 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70* 71 72* 73 74 75 76 77 78 79 80* 81 82 83 84 85 86 87 88* 89* 90* 91* 92* 93* 94* 95* Basically the user has *really* messed up its configuration :) Nodes 0 (CPUs 0-23), 2 (CPUs 48-71) and 3 (CPUs 72-95) are easy: in all cases at least one of the secondary threads is online, so we should fallback to the subcore-unaware logic and just count the online CPUs. Node 1 (CPUs 24-47) is different, though: all the primary threads are online, and all the secondary threads are offline, just like they're supposed to. How should the threads in node 1 be counted, then? Should the subcore-aware logic be applied (resulting in 41 online CPUs overall) or should we use the fallback logic for all nodes because at least one of them is violating our expectations (resulting in 20 online CPUs overall)? I'm tending towards "it doesn't really matter", eg. if you mess with the configuration you can't expect the reported capacity to make any sense. I'd probably go with the former option (because it requires less changes to the code) and add a paragraph about it to the documentation, but I'd love to hear your opinion on the subject. Cheers. -- Andrea Bolognani Software Engineer - Virtualization Team