lkml.org 
[lkml]   [2012]   [Jul]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 08/11] perf tool: precise mode requires exclude_guest
    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.

    -Robert

    --
    Advanced Micro Devices, Inc.
    Operating System Research Center



    \
     
     \ /
      Last update: 2012-07-24 19:21    [W:4.257 / U:0.248 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site