cpu-passthrough Sent from my iPhone
On Mar 4, 2020, at 9:24 PM, rui zang <rui.zang@yandex.com> wrote:
Hi,
What is the value for the "cpu_mode" configuration option? https://docs.openstack.org/mitaka/config-reference/compute/hypervisor-kvm.ht...
Thanks, Zang, Rui
05.03.2020, 01:24, "Satish Patel" <satish.txt@gmail.com>: Folks,
We are running openstack with KVM and i have noticed kvm presenting wrong CPU Tolopoly to VM and because of that we are seeing bad performance to our application.
This is openstack compute:
# lstopo-no-graphics --no-io Machine (64GB total) NUMANode L#0 (P#0 32GB) + Package L#0 + L3 L#0 (25MB) L2 L#0 (256KB) + L1d L#0 (32KB) + L1i L#0 (32KB) + Core L#0 PU L#0 (P#0) PU L#1 (P#20) L2 L#1 (256KB) + L1d L#1 (32KB) + L1i L#1 (32KB) + Core L#1 PU L#2 (P#1) PU L#3 (P#21)
This is VM running on above compute
# lstopo-no-graphics --no-io Machine (59GB total) NUMANode L#0 (P#0 29GB) + Package L#0 + L3 L#0 (16MB) L2 L#0 (4096KB) + Core L#0 L1d L#0 (32KB) + L1i L#0 (32KB) + PU L#0 (P#0) L1d L#1 (32KB) + L1i L#1 (32KB) + PU L#1 (P#1) L2 L#1 (4096KB) + Core L#1 L1d L#2 (32KB) + L1i L#2 (32KB) + PU L#2 (P#2) L1d L#3 (32KB) + L1i L#3 (32KB) + PU L#3 (P#3)
if you noticed P#0 and P#1 has own (32KB) cache per thread that is wrong presentation if you compare with physical CPU.
This is a screenshot of AWS vs Openstack CPU Topology and looking at openstack its presentation is little odd, is that normal?
I am running CentOS7.6 with kvm 2.12 version.