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

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Message-ID: <20120222133404.GA14085@elte.hu>
Date:	Wed, 22 Feb 2012 14:34:05 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	"H. Peter Anvin" <hpa@...or.com>, Jason Baron <jbaron@...hat.com>,
	a.p.zijlstra@...llo.nl, 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


* Steven Rostedt <rostedt@...dmis.org> wrote:

> I like the blue shed, but anyway...
> 
> On Wed, 2012-02-22 at 09:06 +0100, Ingo Molnar wrote:
> > * 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! 
> 
> I mentioned this thread on irc and the first comment I received was:
> 
> "is that a new attempt at trying to guide the compiler?"

It essentially is, implemented partly via compiler help, 
combined with runtime code patching, as an extended run-time arm 
of the compiler in essence, to make out of line slowpaths even 
cheaper to have around - to make the fast-path even faster.

> I personally find the very_unlikely() confusing, but then 
> again I like the blue shed over the pink one.

Confusing in what way?

Thanks,

	Ingo
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