linux-kernel - Re: [PATCH 00/10] jump label: introduce very

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Message-ID: <20120222080659.GA25318@elte.hu>
Date:	Wed, 22 Feb 2012 09:06:59 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Jason Baron <jbaron@...hat.com>, a.p.zijlstra@...llo.nl,
	rostedt@...dmis.org, mathieu.desnoyers@...icios.com,
	davem@...emloft.net, ddaney.cavm@...il.com,
	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 00/10] jump label: introduce very_[un]likely + cleanups +
 docs

* H. Peter Anvin <hpa@...or.com> wrote:

> Not arguing that, but the static aspect is still key... or 
> people will read it as another version of likely/unlikely.  

They can *read* it as such, that as is very much intentional! 

People reading such code should indeed treat it as a branch 
probability attribute (and ignore it in 99.9% of the cases).

The moment they *write* static_cond_slow_inc() in real code 
though they will be warned about the speciality and slowness of 
the update path. More so than they are warned by the current 
jump_label_inc() name, me thinks.

> I'd be fine with static_likely/unlikely for example; I wish 
> "static" wasn't such an overloaded word in C but I 
> can't.personally think of a better term.

Yeah, we considered static_likely()/unlikely() but it is indeed 
overloaded *way* too much, so we went for 
very_likely()/very_unlikely() which also fairly conveys the real 
meaning at the usage site ...

I think the naming scheme I suggested in the other mail 
sufficienty carries both the attribute, bias and update cost 
aspects.

Thanks,

	Ingo
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