Messages in this thread | | | Subject | Re: [PATCH] KVM: Disable wake-affine vCPU process to mitigate lock holder preemption | From | Dario Faggioli <> | Date | Thu, 01 Aug 2019 14:57:50 +0200 |
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On Tue, 2019-07-30 at 17:33 +0800, Wanpeng Li wrote: > However, in multiple VMs over-subscribe virtualization scenario, it > increases > the probability to incur vCPU stacking which means that the sibling > vCPUs from > the same VM will be stacked on one pCPU. I test three 80 vCPUs VMs > running on > one 80 pCPUs Skylake server(PLE is supported), the ebizzy score can > increase 17% > after disabling wake-affine for vCPU process. > Can't we achieve this by removing SD_WAKE_AFFINE from the relevant scheduling domains? By acting on /proc/sys/kernel/sched_domain/cpuX/domainY/flags, I mean?
Of course this will impact all tasks, not only KVM vcpus. But if the host does KVM only anyway...
Regards -- Dario Faggioli, Ph.D http://about.me/dario.faggioli Virtualization Software Engineer SUSE Labs, SUSE https://www.suse.com/ ------------------------------------------------------------------- <<This happens because _I_ choose it to happen!>> (Raistlin Majere)
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