Re: [PATCH 2/5] kvmtrace: make cycle calculation architecture aware

[Avi Kivity <avi@qumranet.com>]

Yang, Sheng wrote:
> On Wednesday 09 July 2008 23:03:19 Hollis Blanchard wrote:
>   
>> On Wed, 2008-07-09 at 11:17 +0200, Christian Ehrhardt wrote:
>>     
>>> So the question that is left before changing that is, if the
>>> original author had something special in mind chosing cycles
>>> here. I added Eric on CC for that.
>>>
>>> I wait with my resubmission of the patch series until all
>>> architectures agree *hope* on using getnstimeofday() - after an
>>> ack from all sides I would revise my patch series and submit that
>>> changes alltogether.
>>>       
>> I got an email bounce from Eric the last time I tried to email him,
>> so I'm not sure he's still with Intel.
>>
>> However, I don't think he had any special intention; I think he was
>> just porting xentrace to KVM.
>>     
>
> Eric had completed his internship in Intel, so...
>
> I like the term "timestamp" too. I think he used "cycles" only because 
> there is a function called get_cycles().
>
> But instead of getnstimeofday(), I suggest using ktime_get() here. 
> It's little more precise than getnstimeofday(), and ktime_t is more 
> easily to be handled. And I think the overhead it brought can be 
> ignored too.
>   

What is the overhead of ktime_get()?

-- 
error compiling committee.c: too many arguments to function