From: Avi Kivity <avi@redhat.com>
To: David Ahern <dsahern@gmail.com>
Cc: Gleb Natapov <gleb@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: perf with precise attribute kills all KVM based VMs
Date: Sun, 15 Jul 2012 16:03:23 +0300 [thread overview]
Message-ID: <5002BF9B.8090306@redhat.com> (raw)
In-Reply-To: <5002BEE3.5060506@gmail.com>
On 07/15/2012 04:00 PM, David Ahern wrote:
> On 7/15/12 2:07 AM, Avi Kivity wrote:
>> On 07/12/2012 07:06 PM, Gleb Natapov wrote:
>>>>
>>>> Note the :pH this time.
>>> I am not sure what perf kvm does with :pH modifier, but H modifier does
>>> not make sense with perf kvm and should be reported as an error by
>>> perf tool.
>>
>> Maybe it should refer to the guest vs. the nested guest...
>
> :H = host mode; you are thinking of :h for hypervisor mode. From
> perf-list documentation:
>
> "Modifiers allow the user to restrict when events are
> counted with 'u' for user-space, 'k' for kernel, 'h' for hypervisor.
> Additional modifiers are 'G' for guest counting (in KVM guests) and 'H'
> for host counting (not in KVM guests)."
No, it's an additional distinction. A kvm guest can be in kernel mode,
user mode, or in a nested guest mode (which has its own user mode and
kernel mode). Currently we have no way of distinguishing between guest
kernel mode and nested guest kernel mode.
I assume 'h' means profiling the hypervisor from a guest (i.e. xen dom0)?
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-07-15 13:03 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-09 14:12 perf with precise attribute kills all KVM based VMs David Ahern
2012-07-09 14:19 ` Gleb Natapov
2012-07-09 14:24 ` Peter Zijlstra
2012-07-09 14:36 ` Gleb Natapov
2012-07-09 14:39 ` Avi Kivity
2012-07-09 14:47 ` David Ahern
2012-07-09 14:49 ` Peter Zijlstra
2012-07-09 14:51 ` Avi Kivity
2012-07-09 14:54 ` Gleb Natapov
2012-07-09 14:57 ` Gleb Natapov
2012-07-09 14:59 ` Peter Zijlstra
2012-07-10 23:38 ` David Ahern
2012-07-11 7:10 ` Gleb Natapov
2012-07-11 9:49 ` Peter Zijlstra
2012-07-11 9:53 ` Gleb Natapov
2012-07-11 13:34 ` David Ahern
2012-07-12 4:11 ` David Ahern
2012-07-12 4:29 ` Gleb Natapov
2012-07-12 15:20 ` David Ahern
2012-07-12 16:06 ` Gleb Natapov
2012-07-12 16:13 ` Gleb Natapov
2012-07-12 16:58 ` Peter Zijlstra
2012-07-16 1:51 ` David Ahern
2012-07-15 8:07 ` Avi Kivity
2012-07-15 13:00 ` David Ahern
2012-07-15 13:03 ` Avi Kivity [this message]
2012-07-16 1:52 ` David Ahern
2012-07-16 2:19 ` David Ahern
2012-07-20 23:34 ` David Ahern
2012-07-22 9:52 ` Avi Kivity
2012-07-09 14:52 ` David Ahern
2012-07-09 14:58 ` David Ahern
2012-07-09 15:18 ` David Ahern
2012-07-09 14:47 ` Peter Zijlstra
2012-07-20 23:35 ` David Ahern
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