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From: Erik Rull <erik.rull@rdsoftware.de>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Enabling Hyperthreading for Guest
Date: Thu, 22 Sep 2011 18:43:04 +0200	[thread overview]
Message-ID: <4E7B6598.307@rdsoftware.de> (raw)
In-Reply-To: <1316635372.4443.104.camel@bling.home>

Alex Williamson wrote:
> See the extended -smp options:
>
> -smp n[,maxcpus=cpus][,cores=cores][,threads=threads][,sockets=sockets]
>                  set the number of CPUs to 'n' [default=1]
>                  maxcpus= maximum number of total cpus, including
>                  offline CPUs for hotplug, etc
>                  cores= number of CPU cores on one socket
>                  threads= number of threads on one CPU core
>                  sockets= number of discrete sockets in the system
>
> Try something like:
>
> -smp 4,cores=2,threads=2,sockets=1
>
> Alex
>

Great - the correct combination made it :-)

But the SMP-Performance-Benchmark is horrible :-(
"Only" between 0.35 and 1.05 for the above combination.
I have the same architecture on the host (2 cores w/ ht enabled) so there 
are enough real cores available for computation.

Any idea what could slow down the performance here?

Best regards,

Erik

  reply	other threads:[~2011-09-22 16:42 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-21 13:02 [Qemu-devel] Enabling Hyperthreading for Guest erik.rull
2011-09-21 20:02 ` Alex Williamson
2011-09-22 16:43   ` Erik Rull [this message]
2011-09-22 17:15     ` Alex Williamson
2011-09-23 15:29       ` Erik Rull
2011-09-23 16:49         ` Alex Williamson

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