linux-kernel - Re: [PATCH v2 2/4] perf: streamline append

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Date:	Mon, 21 Oct 2013 10:50:38 -0400
From:	Waiman Long <waiman.long@...com>
To:	Andi Kleen <andi@...stfloor.org>
CC:	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Jiri Olsa <jolsa@...hat.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	David Ahern <dsahern@...il.com>,
	Stephane Eranian <eranian@...gle.com>,
	linux-kernel@...r.kernel.org,
	Aswin Chandramouleeswaran <aswin@...com>,
	Scott J Norton <scott.norton@...com>
Subject: Re: [PATCH v2 2/4] perf: streamline append_chain() function

On 10/19/2013 08:29 PM, Andi Kleen wrote:
> Waiman Long<Waiman.Long@...com>  writes:
>
>> as well as
>> using ?: statement which can be more efficient than the regular if
>> statement in some architectures.
> I don't think that's true, the compiler does if conversion anyways for both.
>
> But change seems reasonable.
>
> -Andi
>
>

That may be true for a simple if statement. However, the condition was 
checked as the last of 3 tests. I doubt if the compiler is able to 
optimize that effectively.

-Longman
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