Hi Peter Thanks. Yes, I believe (Sockets,Cores,Threads) = (1,16,1) should be the best performance, as the VM does not need to access the memory of another NUMA node.
So, is it a bug that Virt Manager uses more Sockets by default, when i choose "Copy host CPU Configuration" ? regards, Rajesh A Engineering Media Movement Media Services Direct +91 44 66674575 | Mobile +91 9043011101 | IP 564575 rajes...@tatacommunications.com<mailto:rajes...@tatacommunications.com> [cid:image001.jpg@01D86AAD.F02877A0] <http://tatacommunications.com/> www.tatacommunications.com<http://www.tatacommunications.com/> [cid:image002.jpg@01D86AAD.F02877A0]<https://twitter.com/#!/tata_comm> @tata_comm<https://twitter.com/#!/tata_comm> From: Peter Zay <peterz...@gmail.com> Sent: 18 May 2022 01:33 AM To: Rajesh A <rajes...@tatacommunications.com> Cc: qemu-disc...@nongnu.org; qemu-devel@nongnu.org; Ramya R (GIMEC) <ramy...@tatacommunications.com>; V G ASHWINI . <ashwini...@contractor.tatacommunications.com> Subject: Re: QEMU cpu socket allocation CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe. Hi Rajesh, Would the more intuitive CPU setting of (Sockets,Cores,Threads) = (1,16,1) be ok? Thanks. On Tue, May 17, 2022 at 10:03 AM Rajesh A <rajes...@tatacommunications.com<mailto:rajes...@tatacommunications.com>> wrote: Hi QEMU dev Virt Manager is able to configure a QEMU VM with more CPU sockets than the physical host has. For example, in the below VM, when I request 16 vCPU cores, by default it takes as 16 Sockets with 1 core each. The host itself has only 2 Sockets. 1. How does QEMU allow this and how the VM works? 2. What is the recommended configuration of Sockets/Cores/Threads for best VM performance of a 16 core VM running on a 2 sockets host ? [cid:image003.png@01D86AAD.F02877A0] regards, Rajesh A Engineering Media Movement Media Services Direct +91 44 66674575 | Mobile +91 9043011101 | IP 564575 rajes...@tatacommunications.com<mailto:rajes...@tatacommunications.com> [cid:image001.jpg@01D86AAD.F02877A0] <https://apc01.safelinks.protection.outlook.com/?url=http%3A%2F%2Ftatacommunications.com%2F&data=05%7C01%7Crajesh.a%40tatacommunications.com%7C34740206d7594bd2c2cc08da38405798%7C202104622c5e4ec8b3e20be950f292ca%7C0%7C0%7C637884146402124571%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=RwEq2mM%2FD6EPV3weUzP1i87N7n%2Fxe619qWQzJjSYpVg%3D&reserved=0> www.tatacommunications.com<https://apc01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.tatacommunications.com%2F&data=05%7C01%7Crajesh.a%40tatacommunications.com%7C34740206d7594bd2c2cc08da38405798%7C202104622c5e4ec8b3e20be950f292ca%7C0%7C0%7C637884146402124571%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=CeVSNB1CC9Dn%2BRvtUdQAH13eTvPhjyYhk%2FVaW66yy3o%3D&reserved=0> [cid:image002.jpg@01D86AAD.F02877A0]<https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftwitter.com%2F%23!%2Ftata_comm&data=05%7C01%7Crajesh.a%40tatacommunications.com%7C34740206d7594bd2c2cc08da38405798%7C202104622c5e4ec8b3e20be950f292ca%7C0%7C0%7C637884146402124571%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=Kqv3RAl3ZhDXSkPJeSJV2IRwewLPsoOf5fdVE%2BPm8iw%3D&reserved=0> @tata_comm<https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftwitter.com%2F%23!%2Ftata_comm&data=05%7C01%7Crajesh.a%40tatacommunications.com%7C34740206d7594bd2c2cc08da38405798%7C202104622c5e4ec8b3e20be950f292ca%7C0%7C0%7C637884146402124571%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=Kqv3RAl3ZhDXSkPJeSJV2IRwewLPsoOf5fdVE%2BPm8iw%3D&reserved=0> -- Peter
