On Mon, Mar 2, 2020 at 4:51 PM Michal Skrivanek <michal.skrivanek@redhat.com> wrote:
I have this cpu flag set: invpcid_single
Instead on the same host in 4.3.5 (eg kernel 3.10.0-1062.el7.x86_64) the
flag is not set.
sometimes there are kernel changes like that, but more usually it’s just the microcode version on each host (not bios), did you check that too?
I do think so too. The microcode update from 4.3.5 to 4.3.8 consists in microcode_ctl passing from microcode_ctl-2.1-53.el7.x86_64 to microcode_ctl-2.1-53.7.el7_7.x86_64. And in the mean time this solution has been created, that confirms the flag introduced for Meltdown mitigations: https://access.redhat.com/solutions/4866021
Now you can remove the "Pass-Through Host CPU" flag --> remove it
but then you’re losing probably the biggest differentiator for “high performance”, so then maybe not use that profile at all?
Yes, you are right ;-) I used it mainly for enabling I/O threads and testing on huge pages (and different icon display ...) Gianluca