[Qemu-discuss] cpu socket/cores/threads nor extra flags not showing up in guest's cpuinfo

[Nelson, Bjorn]

Hi,

 

I am trying to use the -smp option to setup a couple different layouts for the cpu but am finding that it doesn’t respect them.  I can either go all cpus or all cores, but not some mix of the two. 

 

`> /ms/dist/fsf/PROJ/qemu/1.0/bin/qemu-system-x86_64 -version

QEMU emulator version 1.0, Copyright (c) 2003-2008 Fabrice Bellard

-smp cores=4,sockets=2,threads=1

-smp cores=2,sockets=2,threads=2

 

Results in /proc/cpuinfo output showing for all physical id: 0 but cores: 1 and siblings: 8

 

-smp 8

 

Results in /proc/cpuinfo output showing 8 with different physical ids which makes sense.

 

This is with version qemu 1.0 with cpu qemu64.  Also, for some reason using -cpu qemu64,+sse3,+sse4.1,+sse4.2, didn’t enable these cpu flags in the guest either.  I get the same behavior with -cpu Nehalem (which is the underlying hardware). 

 

I tried setting different -numa ids to see if that would help trigger something, but it didn’t help.  Also I tried this with the kvm binary version 0.12.1 where it seemed to work.  My guess is there isn’t much performance different between all cpus and all cores under a vm, but if someone can confirm that, I would appreciate it. 

 

-Bjorn   

---

NOTICE: Morgan Stanley is not acting as a municipal advisor and the opinions or views contained herein are not intended to be, and do not constitute, advice within the meaning of Section 975 of the Dodd-Frank Wall Street Reform and Consumer Protection Act. If you have received this communication in error, please destroy all electronic and paper copies and notify the sender immediately. Mistransmission is not intended to waive confidentiality or privilege. Morgan Stanley reserves the right, to the extent permitted under applicable law, to monitor electronic communications. This message is subject to terms available at the following link: http://www.morganstanley.com/disclaimers. If you cannot access these links, please notify us by reply message and we will send the contents to you. By messaging with Morgan Stanley you consent to the foregoing.