Message-ID: <1344562886.6935.93.camel@gandalf.stny.rr.com>
Subject: Re: [RFC][PATCH] tracepoints: Move the work out of line from
 hotpath sections
From: Steven Rostedt <rostedt@goodmis.org>
To: David Daney <ddaney.cavm@gmail.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
        Avi Kivity <avi@redhat.com>, Christoph Hellwig <hch@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>
Date: Thu, 09 Aug 2012 21:41:26 -0400
In-Reply-To: <50244D9A.2070000@gmail.com>
References: <1344544823.6935.82.camel@gandalf.stny.rr.com>
	  <20120809205053.GB15109@Krystal>
	 <1344551131.6935.90.camel@gandalf.stny.rr.com>
	 <502444CC.8030906@linux.intel.com> <50244D9A.2070000@gmail.com>
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On Thu, 2012-08-09 at 16:54 -0700, David Daney wrote:
> On 08/09/2012 04:16 PM, H. Peter Anvin wrote:
> > On 08/09/2012 03:25 PM, Steven Rostedt wrote:
> >>>
> >>> It might be better to improve gcc to move really cold branches out of
> >>> line (really, really far away), and use the compiler to do this, rather
> >>> than to use an extra indirection that adds bloat and complexity to the
> >>> kernel.
> 
> Oh, you mean like: -freorder-blocks-and-partition

Actually, what would be really nice is to place a block in a section of
your choice. Something like:


	if (unlikely(x)) __attribute__((section(".unlikely"))) {
		/* code here will be in the ".unlikely" section */
	}

-- Steve


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