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Date: Thu, 10 Sep 2009 17:08:27 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] Re: [PATCH 05/26] Unexport ticks_per_sec variable.
	Create get_ticks_per_sec() function
References: <cover.1252543871.git.quintela@redhat.com>
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To: malc <av1474@comtv.ru>
Cc: qemu-devel@nongnu.org, Juan Quintela <quintela@redhat.com>

malc wrote:
> On Thu, 10 Sep 2009, Anthony Liguori wrote:
>
>   
>> malc wrote:
>>     
>>> My problem with this patch is that it is completely pointless, touches
>>> a gob of places and the fact that you apparently never seen what a
>>> function call entails on PPC64 (any ABI).
>>>   
>>>       
>> But there is nothing to suggest this variable is every in the fast path 
>> so any overhead argument is unfounded.
>>
>> More importantly, using a function to access this variable gives us the
>> ability to change how the behavior is implemented without touching a gob of
>> places.
>>
>>     
>
> Untill such an ability is needed, the patch adds nothing,

Except that it eliminates the possibility of misusing the interface and 
setting it somewhere it shouldn't be.

It makes the code more defensive because you cannot accidentally use it 
like it's a local variable.  The key bit of the patch is:

-int64_t ticks_per_sec;
+static int64_t ticks_per_sec;


That is *always* a worthwhile change to make.  We need more patches like 
this.

Regards,

Anthony Liguori