On 15/12/19 15:43, Prarit Bhargava wrote: >>> Oh, I wasn't pointing out that it wasn't just lost, I was pointing out >>> that NO_HZ_IDLE is not set because we run NO_HZ_FULL. We were one of >>> the first distros to do so, and it has worked well for us. I have a >>> fairly strong opinion about not dropping back to IDLE without good >>> reason. >> >> This wasn't a proposal to change anything here at all, sorry if that >> was the way it read. I was purely wondering, while digging through >> stuff around cpu idle, for the difference between arches. >> >> With the hit around NO_HZ_IDLE vs NO_HZ_FULL I dug some more and >> basically it seems the reason we don't have the later on the non >> x86_64 arches is because for some reason we unset >> VIRT_CPU_ACCOUNTING_GEN for all except x86_64, it looks to be >> historical, all our current architectures now look to support that >> option. Anyone aware of any reason we shouldn't use the >> NO_HZ_FULL/VIRT_CPU_ACCOUNTING_GEN as standard across all arches? > > I don't know of a reason -- pbonzini? Have any input here?
No reason I know of, though note that VIRT_CPU_ACCOUNTING has nothing to do with virtualization so my opinion may not count much. :) IIRC there is no overhead for VIRT_CPU_ACCOUNTING unless context tracking is enabled, is that correct? It should be all hidden behind a static key. Paolo _______________________________________________ kernel mailing list -- [email protected] To unsubscribe send an email to [email protected] Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/[email protected]
