Re: [PATCH v2 5/6] KVM: trace kvm_ple_window

From: Paolo Bonzini <pbonzini@redhat.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Gleb Natapov <gleb@kernel.org>,
	Raghavendra KT <raghavendra.kt@linux.vnet.ibm.com>,
	Vinod Chegu <chegu_vinod@hp.com>, Hui-Zhi <hui-zhi.zhao@hp.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>
Subject: Re: [PATCH v2 5/6] KVM: trace kvm_ple_window
Date: Thu, 21 Aug 2014 15:22:50 +0200	[thread overview]
Message-ID: <53F5F2AA.7060600@redhat.com> (raw)
In-Reply-To: <20140821115637.GE20546@potion.brq.redhat.com>

Il 21/08/2014 13:56, Radim Krčmář ha scritto:
> 2014-08-21 10:29+0200, Paolo Bonzini:
>> Il 20/08/2014 22:53, Radim Krčmář ha scritto:
>>> Tracepoint for dynamic PLE window, fired on every potential change.
>>>
>>> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
>>> ---
>>>  arch/x86/kvm/trace.h | 25 +++++++++++++++++++++++++
>>>  arch/x86/kvm/vmx.c   |  8 +++++---
>>>  arch/x86/kvm/x86.c   |  1 +
>>>  3 files changed, 31 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
>>> index e850a7d..4b8e6cb 100644
>>> --- a/arch/x86/kvm/trace.h
>>> +++ b/arch/x86/kvm/trace.h
>>> @@ -848,6 +848,31 @@ TRACE_EVENT(kvm_track_tsc,
>>>  		  __print_symbolic(__entry->host_clock, host_clocks))
>>>  );
>>>  
>>> +TRACE_EVENT(kvm_ple_window,
>>> +	TP_PROTO(int grow, unsigned int vcpu_id, int new, int old),
>>
>> s/int grow/bool grow/ (and similarly in TP_STRUCT__entry).
> 
> Ok.
> (We are using 'int' for this in other tracepoints, so I guessed there is
>  some hate agains bool.)

Yeah, there are many ints, but there are also some bools. :)

Of course "bool" is only a no-brainer if there is a clear direction to
use (e.g. "bool has_error"), and indeed this case is less obvious.  But
there are some like this one (e.g. bool gpa_match).

Keep the int if you prefer it that way.

Paolo

>>> +	TP_ARGS(grow, vcpu_id, new, old),
>>> +
>>> +	TP_STRUCT__entry(
>>> +		__field(                 int,      grow         )
>>> +		__field(        unsigned int,   vcpu_id         )
>>> +		__field(                 int,       new         )
>>> +		__field(                 int,       old         )
>>> +	),
>>> +
>>> +	TP_fast_assign(
>>> +		__entry->grow           = grow;
>>> +		__entry->vcpu_id        = vcpu_id;
>>> +		__entry->new            = new;
>>> +		__entry->old            = old;
>>> +	),
>>> +
>>> +	TP_printk("vcpu %u: ple_window %d %s %d",
>>> +	          __entry->vcpu_id,
>>> +	          __entry->new,
>>> +	          __entry->grow ? "<+" : "<-",
>>
>> ? "grow" : "shrink"
> 
> Can't say I haven't expected comment about that :)
> 