Am 08.01.2018 um 23:07 schrieb Eric Blake: > On 01/08/2018 02:03 PM, Stefan Priebe - Profihost AG wrote: >> Hello, >> >> for meltdown mitigation and performance it's important to have the pcid >> flag passed down to the guest (f.e. >> https://groups.google.com/forum/m/#!topic/mechanical-sympathy/L9mHTbeQLNU). > > Indeed; you are still waiting on the qemu patch mentioned here: > https://www.qemu.org/2018/01/04/spectre/ > > which is still undergoing the review process, but should be up (in the > form of 2.11.1) "in the next few days".
OK thanks as the performance difference is significant: no pcid: # time for i in $(seq 1 1 50); do du -sx /; done ... real 0m26.614s user 0m17.548s sys 0m9.056s kvm started with +pcid: # time for i in $(seq 1 1 50); do du -sx /; done ... real 0m14.734s user 0m7.755s sys 0m6.973s Greets, Stefan
