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Message #46975
[Bug 1550317] [NEW] 'hw:cpu_thread_policy=isolate' does not schedule on non-HT hosts
Public bug reported:
The 'isolate' policy is supposed to function on both hosts with
HyperThreading (HT) and those without. The former works, but the latter
does not. This appears to be a regression. Results below.
---
# Platform
Testing was conducted on two single-node, Fedora 23-based
(4.3.5-300.fc23.x86_64) OpenStack instances (built with devstack). The systems
are a dual-socket, ten core, systems with HT enabled on one and disabled
on the other (2 sockets * 10 cores * 1/2 threads
= 20/40 "pCPUs". 0-9/0-9,20-29 = node0, 10-19/10-19,30-39 = node1).
Commit `8bafc9` of Nova was used.
# Steps
## Create flavors
$ openstack flavor create pinned.isolate \
--id 103 --ram 2048 --disk 0 --vcpus 4
$ openstack flavor set pinned.isolate \
--property "hw:cpu_policy=dedicated" \
--property "hw:cpu_thread_policy=isolate"
## Validate a HT-enabled node
This should match the expectations of the spec and provide a single thread
to guests while avoiding other guests scheduling on the other host
sibling threads. Therefore, the guest should see four sockets, one core
per socket, and one thread per core.
$ openstack server create --flavor=pinned.isolate \
--image=cirros-0.3.4-x86_64-uec --wait test1
$ sudo virsh list
Id Name State
----------------------------------------------------
3 instance-00000003 running
$ sudo virsh dumpxml 3
<domain type='kvm' id='3'>
<name>instance-00000003</name>
...
<vcpu placement='static'>4</vcpu>
<cputune>
<shares>4096</shares>
<vcpupin vcpu='0' cpuset='1'/>
<vcpupin vcpu='1' cpuset='0'/>
<vcpupin vcpu='2' cpuset='25'/>
<vcpupin vcpu='3' cpuset='8'/>
<emulatorpin cpuset='0-1,8,25'/>
</cputune>
<numatune>
<memory mode='strict' nodeset='0'/>
<memnode cellid='0' mode='strict' nodeset='0'/>
</numatune>
...
<cpu>
<topology sockets='4' cores='1' threads='1'/>
<numa>
<cell id='0' cpus='0-3' memory='2097152' unit='KiB'/>
</numa>
</cpu>
...
</domain>
$ openstack server delete test1
No problems here.
## Validate a HT-disabled node
This should work exactly the same here as it did on the HT-enabled host,
minus the reservation of any thread sibling (there aren't any)
$ openstack server create --flavor=pinned.isolate \
--image=cirros-0.3.4-x86_64-uec --wait test1
Error creating server: test1
Error creating server
$ openstack server list
+--------------------------------------+-------+--------+----------+
| ID | Name | Status | Networks |
+--------------------------------------+-------+--------+----------+
| 1f212d45-585e-41df-abd7-6abb12ca86a1 | test1 | ERROR | |
+--------------------------------------+-------+--------+----------+
** Affects: nova
Importance: Undecided
Status: New
--
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to OpenStack Compute (nova).
https://bugs.launchpad.net/bugs/1550317
Title:
'hw:cpu_thread_policy=isolate' does not schedule on non-HT hosts
Status in OpenStack Compute (nova):
New
Bug description:
The 'isolate' policy is supposed to function on both hosts with
HyperThreading (HT) and those without. The former works, but the
latter does not. This appears to be a regression. Results below.
---
# Platform
Testing was conducted on two single-node, Fedora 23-based
(4.3.5-300.fc23.x86_64) OpenStack instances (built with devstack). The systems
are a dual-socket, ten core, systems with HT enabled on one and disabled
on the other (2 sockets * 10 cores * 1/2 threads
= 20/40 "pCPUs". 0-9/0-9,20-29 = node0, 10-19/10-19,30-39 = node1).
Commit `8bafc9` of Nova was used.
# Steps
## Create flavors
$ openstack flavor create pinned.isolate \
--id 103 --ram 2048 --disk 0 --vcpus 4
$ openstack flavor set pinned.isolate \
--property "hw:cpu_policy=dedicated" \
--property "hw:cpu_thread_policy=isolate"
## Validate a HT-enabled node
This should match the expectations of the spec and provide a single thread
to guests while avoiding other guests scheduling on the other host
sibling threads. Therefore, the guest should see four sockets, one core
per socket, and one thread per core.
$ openstack server create --flavor=pinned.isolate \
--image=cirros-0.3.4-x86_64-uec --wait test1
$ sudo virsh list
Id Name State
----------------------------------------------------
3 instance-00000003 running
$ sudo virsh dumpxml 3
<domain type='kvm' id='3'>
<name>instance-00000003</name>
...
<vcpu placement='static'>4</vcpu>
<cputune>
<shares>4096</shares>
<vcpupin vcpu='0' cpuset='1'/>
<vcpupin vcpu='1' cpuset='0'/>
<vcpupin vcpu='2' cpuset='25'/>
<vcpupin vcpu='3' cpuset='8'/>
<emulatorpin cpuset='0-1,8,25'/>
</cputune>
<numatune>
<memory mode='strict' nodeset='0'/>
<memnode cellid='0' mode='strict' nodeset='0'/>
</numatune>
...
<cpu>
<topology sockets='4' cores='1' threads='1'/>
<numa>
<cell id='0' cpus='0-3' memory='2097152' unit='KiB'/>
</numa>
</cpu>
...
</domain>
$ openstack server delete test1
No problems here.
## Validate a HT-disabled node
This should work exactly the same here as it did on the HT-enabled host,
minus the reservation of any thread sibling (there aren't any)
$ openstack server create --flavor=pinned.isolate \
--image=cirros-0.3.4-x86_64-uec --wait test1
Error creating server: test1
Error creating server
$ openstack server list
+--------------------------------------+-------+--------+----------+
| ID | Name | Status | Networks |
+--------------------------------------+-------+--------+----------+
| 1f212d45-585e-41df-abd7-6abb12ca86a1 | test1 | ERROR | |
+--------------------------------------+-------+--------+----------+
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