Bug 725268 - -smp 1,cores=2 has weird semantics
Summary: -smp 1,cores=2 has weird semantics
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: qemu-kvm
Version: 6.2
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Virtualization Maintenance
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2011-07-24 22:32 UTC by Cole Robinson
Modified: 2013-01-10 00:08 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2011-08-11 21:44:14 UTC
Target Upstream Version:


Attachments (Terms of Use)

Description Cole Robinson 2011-07-24 22:32:49 UTC
I'd expect -smp 1,cores=2 to give me a guest with a dual core socket == 2 logical CPUs exposed to the guest. Instead I see just 1 logical CPU in /proc/cpuinfo: a socket claiming 2 cores but only 1 core is listed.

Ideally I'd think that if any topology info is specified, old style -smp X is ignored, and the logical CPU number is just calculated, defaulting unspecified topology values to 1. Or have old style -smp X just be the old way of specifying sockets=X, and if sockets= is specified, -smp X is ignored.

And even if nothing is changed the docs should mention these semantics (which isn't really relevant for RHEL but still worth mentioning).

(see https://bugzilla.redhat.com/show_bug.cgi?id=708892#c2 for some more background)

Comment 2 Dor Laor 2011-08-11 21:44:14 UTC
(In reply to comment #0)
> I'd expect -smp 1,cores=2 to give me a guest with a dual core socket == 2
> logical CPUs exposed to the guest. Instead I see just 1 logical CPU in
> /proc/cpuinfo: a socket claiming 2 cores but only 1 core is listed.

I think the current syntax requires -smp 2, cores=2.
Agree it is not the easiest. I doubt we'll be able to change it now.
If the above does not work, please reopen the bug

> 
> Ideally I'd think that if any topology info is specified, old style -smp X is
> ignored, and the logical CPU number is just calculated, defaulting unspecified
> topology values to 1. Or have old style -smp X just be the old way of
> specifying sockets=X, and if sockets= is specified, -smp X is ignored.
> 
> And even if nothing is changed the docs should mention these semantics (which
> isn't really relevant for RHEL but still worth mentioning).
> 
> (see https://bugzilla.redhat.com/show_bug.cgi?id=708892#c2 for some more
> background)


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