ovirt 4.1 - skylake - no avx512 support in virtual machines
Hi, I can't access avx512* instruction set from virtual machines. I have made a one server compute cluster to test new hardware: oVirt 4.1.9 CentOS 7 Cluster CPU Type: Intel Skylake Family Compatibility Version: 4.1 HOST: CPU Model Name:Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz Family: Family CPU Type: Intel Skylake Family Virtual Machine settings A) VM: Custom CPU Type: Use cluster default(Intel Skylake Family) General Tab shows: Guest CPU Type: Skylake-Client avx512: NO B) VM: Custom CPU Type: Skylake-Client General Tab shows: Guest CPU Type: Skylake-Client avx512: NO C) VM: Custom CPU Type: Use cluster default(Intel Skylake Family) [grey - cannot modify] Migration mode: Do not allow migration Pass-Through Host CPU General Tab shows: Guest CPU Type: Skylake-Client avx512: YES ( cat /proc/cpuinfo |grep avx512: avx512f avx512dq avx512cd avx512bw avx512vl ) Using pass-through host cpu (disabling vm migration) is the only way to access avx512 in a VM, is it a bug or am I missing something? Regards, -- Marco Crociani Prisma Telecom Testing S.r.l. via Petrocchi, 4 20127 MILANO ITALY Phone: +39 02 26113507 Fax: +39 02 26113597 e-mail: marcoc@prismatelecomtesting.com web: http://www.prismatelecomtesting.com
2018-02-26 17:49 GMT+01:00 Marco Lorenzo Crociani < marcoc@prismatelecomtesting.com>:
Hi, I can't access avx512* instruction set from virtual machines.
Added some relevant people.
I have made a one server compute cluster to test new hardware:
oVirt 4.1.9 CentOS 7 Cluster CPU Type: Intel Skylake Family Compatibility Version: 4.1
HOST: CPU Model Name:Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz Family: Family CPU Type: Intel Skylake Family
Virtual Machine settings A) VM: Custom CPU Type: Use cluster default(Intel Skylake Family) General Tab shows: Guest CPU Type: Skylake-Client
avx512: NO
B) VM: Custom CPU Type: Skylake-Client General Tab shows: Guest CPU Type: Skylake-Client
avx512: NO
C) VM: Custom CPU Type: Use cluster default(Intel Skylake Family) [grey - cannot modify] Migration mode: Do not allow migration Pass-Through Host CPU General Tab shows: Guest CPU Type: Skylake-Client
avx512: YES ( cat /proc/cpuinfo |grep avx512: avx512f avx512dq avx512cd avx512bw avx512vl )
Using pass-through host cpu (disabling vm migration) is the only way to access avx512 in a VM, is it a bug or am I missing something?
Regards,
-- Marco Crociani Prisma Telecom Testing S.r.l. via Petrocchi, 4 20127 MILANO ITALY Phone: +39 02 26113507 Fax: +39 02 26113597 e-mail: marcoc@prismatelecomtesting.com web: http://www.prismatelecomtesting.com _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
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On 27/02/2018 09:37, Sandro Bonazzola wrote:
Virtual Machine settings A) VM: Custom CPU Type: Use cluster default(Intel Skylake Family) General Tab shows: Guest CPU Type: Skylake-Client
avx512: NO
B) VM: Custom CPU Type: Skylake-Client General Tab shows: Guest CPU Type: Skylake-Client
avx512: NO
C) VM: Custom CPU Type: Use cluster default(Intel Skylake Family) [grey - cannot modify] Migration mode: Do not allow migration Pass-Through Host CPU General Tab shows: Guest CPU Type: Skylake-Client
avx512: YES ( cat /proc/cpuinfo |grep avx512: avx512f avx512dq avx512cd avx512bw avx512vl )
Using pass-through host cpu (disabling vm migration) is the only way to access avx512 in a VM, is it a bug or am I missing something?
Skylake-Client does _not_ have AVX512 (I tried now on a Kaby Lake Core i7 laptop). Only Skylake-Server has it and it will be in RHEL 7.5. Thanks, Paolo
Skylake-Client does _not_ have AVX512 (I tried now on a Kaby Lake Core i7 laptop). Only Skylake-Server has it and it will be in RHEL 7.5.
Thanks,
Paolo
Ok, we'll stay with pass-through until RHEL 7.5. Thanks, -- Marco Crociani Prisma Telecom Testing S.r.l. via Petrocchi, 4 20127 MILANO ITALY Phone: +39 02 26113507 Fax: +39 02 26113597 e-mail: marcoc@prismatelecomtesting.com web: http://www.prismatelecomtesting.com
On 27 Feb 2018, at 10:53, Marco Lorenzo Crociani <marcoc@prismatelecomtesting.com> wrote:
Skylake-Client does _not_ have AVX512 (I tried now on a Kaby Lake Core i7 laptop). Only Skylake-Server has it and it will be in RHEL 7.5. Thanks, Paolo
Ok, we'll stay with pass-through until RHEL 7.5.
Note that support for Skylake-Server is already in oVirt 4.2.2, once you’re running on a hypervisor which supports that(e.g. RHEL 7.5 beta) it should work, when you run on the exsiting 7.4 it just won’t work (the option is there though, and we separated the generic former “Skylake” to Skylake-Client and Skylake-Server) Thanks, michal
Thanks,
-- Marco Crociani Prisma Telecom Testing S.r.l. via Petrocchi, 4 20127 MILANO ITALY Phone: +39 02 26113507 Fax: +39 02 26113597 e-mail: marcoc@prismatelecomtesting.com web: http://www.prismatelecomtesting.com
participants (4)
-
Marco Lorenzo Crociani -
Michal Skrivanek -
Paolo Bonzini -
Sandro Bonazzola