David,
On 24.07.12 08:20:19, David Ahern wrote:On 7/23/12 12:13 PM, Arnaldo Carvalho de Melo wrote:Em Fri, Jul 20, 2012 at 05:25:53PM -0600, David Ahern escreveu:PEBS cannot be used with guest mode. If user adds :p modifier set
exclude_guest as well.
Is this something Intel specific? Or can someone think of an arch where
this limitation wouldn't exist?
Good point. So far precise_ip is used by arch/x86 only. I don't have an
AMD based server so I don't know if there is a conflict between
virtualization and IBS. Added Robert for advice.
thanks for this hint.
On AMD cpus precise_ip maps to IBS, which does not support hardware
options as perfctrs do. Thus, following attr flags are not supported:
exclude_user, exclude_kernel, exclude_host, exclude_guest
Counting in guest mode is possible with IBS, but not the exclusion of
a certain mode. If precise_ip counting is enabled on AMD we may not
set the exclude_guest flag.