Re: [patch] perf_event_open.2: Exclude_host/exclude_guest clarification

[Michael Kerrisk (man-pages)]

Hi Joerg,

Would you be willing to review/comment on Vince's patch, please.

Cheers,

Michael

On 02/11/2015 08:06 PM, Vince Weaver wrote:
> 
> This patch relates to the exclude_host and exclude_guest bits added 
> by the  following commit:
> 
>    exclude_host, exclude_guest; Linux 3.2
>         commit a240f76165e6255384d4bdb8139895fac7988799
>         Author: Joerg Roedel <joerg.roedel@xxxxxxx>
>         Date:   Wed Oct 5 14:01:16 2011 +0200
> 
>             perf, core: Introduce attrs to count in either host or guest mode
> 
>             Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
>             Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
>             Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
>             Link: http://lkml.kernel.org/r/1317816084-18026-2-git-send-email-gleb@xxxxxxxxxx
>             Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> 
> The updated manpage text clarifies that the "exclude_host" and
> "exclude_guest" perf_event_open() attr bits only apply in the 
> context of a KVM environment and are currently x86 only.
> 
> This is a resend of the patch; the previous time I sent it
> (http://thread.gmane.org/gmane.linux.man/7500) it did not
> receive any comments.
> 
> Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
> 
> diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
> index 39c8d8c..1ea56c9 100644
> --- a/man2/perf_event_open.2
> +++ b/man2/perf_event_open.2
> @@ -1006,11 +1006,25 @@ struct sample_id {
>  .TP
>  .IR "exclude_host" " (since Linux 3.2)"
>  .\" commit a240f76165e6255384d4bdb8139895fac7988799
> -Do not measure time spent in VM host.
> +When conducting measurements that include processes running
> +VM instances (i.e. have executed a
> +.I KVM_RUN
> +.BR ioctl (2)
> +) only measure events happening inside a guest instance.
> +This is only meaningful outside the guests; this setting does
> +not change counts gathered inside of a guest.
> +Currently this functionality is x86 only.
>  .TP
>  .IR "exclude_guest" " (since Linux 3.2)"
>  .\" commit a240f76165e6255384d4bdb8139895fac7988799
> -Do not measure time spent in VM guest.
> +When conducting measurements that include processes running
> +VM instances (i.e. have executed a
> +.I KVM_RUN
> +.BR ioctl (2)
> +) do not measure events happening inside guest instances.
> +This is only meaningful outside the guests; this setting does
> +not change counts gathered inside of a guest.
> +Currently this functionality is x86 only.
>  .TP
>  .IR "exclude_callchain_kernel" " (since Linux 3.7)"
>  .\" commit d077526485d5c9b12fe85d0b2b3b7041e6bc5f91
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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