Very bad performance on Qemu/KVM
From: Nico Schottelius
Date: Tue Oct 16 2012 - 03:58:58 EST
Good morning LKML,
I see extremely slow virtual machines
running on qemu-kvm-0.12.1.2-2.295.el6_3.2.x86_64
on Centos 6.3 with Linux 2.6.32-279.5.2.el6.x86_64 on a
64 core machine using AMD Opteron(TM) Processor 6276 (dell r815).
The guests are Centos 6.3, Linux 2.6.32-220.13.1.el6.x86_64.
The disk images reside on local storage, ext4 filesystem.
I checked that kvm is loaded and enabled. I changed
-drive to use if=virtio, -net to use model=virtio.
>From the processes running it seems that cpu performance is the
bottleneck. I added -cpu host to skip the emulation, but this did
not fix the issue.
Comparing the performance to qemu running on a xenserver, performance is
at most half of it.
Does anyone of you have a good pointer how to debug this further or are
there any known issues with the given setup?
I'm happy for every pointer I get, as there seems to be no easy to spot
PGP key: 7ED9 F7D3 6B10 81D7 0EC5 5C09 D7DC C8E4 3187 7DF0
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/