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From: Ingo Molnar <mingo@elte.hu>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Li Zefan <lizf@cn.fujitsu.com>
Subject: Re: [RFC][PATCH] tracing/module: Move tracepoint out of module.h
Date: Tue, 31 Jan 2012 13:20:16 +0100	[thread overview]
Message-ID: <20120131122016.GF32010@elte.hu> (raw)
In-Reply-To: <87sjiwjzew.fsf@rustcorp.com.au>


* Rusty Russell <rusty@rustcorp.com.au> wrote:

> On Mon, 30 Jan 2012 06:52:13 -0500, Steven Rostedt <rostedt@goodmis.org> wrote:
> > On Fri, 2012-01-27 at 13:32 +1030, Rusty Russell wrote:
> > > On Thu, 26 Jan 2012 19:39:46 +0100, Ingo Molnar <mingo@elte.hu> wrote:
> > > > Ok, i like this one best. Rusty, does it look good to you too?
> > > 
> > > No, the if (module) test belongs in the inline wrapper (since gcc knows
> > > that at compile time).
> > 
> > For some reason though it still adds 5K when we keep the 
> > code as a static inline. Note, my test config does have all 
> > the necessary modules to boot the box as compiled in (not as 
> > modules). If necessary, I could compile with a distro config 
> > and see what the differences are with that.
> > 
> > Rusty, the final decision is yours. If you believe that the 
> > added code size is worth having the static inlines, then 
> > I'll go back to the previous version that had that.
> 
> Wow, we're really bikeshedding this!

Hey, I don't think this is bikesheddig: we are shedding 
*kilobytes* of code from pretty hot codepaths, that kind of 
topic does deserve some detailed attention :-)

> I was completely wrong with the "it's usually a constant" of 
> course; it's usually ->owner.
> 
> So let's just out-of-line the entire thing.  I changed the 
> type to bool and s/_THIS_IP_/_RET_IP_/ -- is that sufficient?
> 
> Doesn't save me much here, though.  What are your stats?

I suspect it depends on inlining options in the .config plus on 
event tracing?

> Saves only 400 bytes of text here, but I don't do preempt or 
> tracepoints.

Most distro kernels do tracepoints so I guess that's where the 
size delta comes from :-) In any case:

Acked-by: Ingo Molnar <mingo@elte.hu>

Thanks,

	Ingo

  reply	other threads:[~2012-01-31 12:20 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-16 22:57 [PATCH][GIT PULL][v3.3] tracing: Add header wrappers event_headers_start.h and event_headers_end.h Steven Rostedt
2012-01-17  9:54 ` Ingo Molnar
2012-01-17 13:32   ` Steven Rostedt
2012-01-18 12:07     ` Ingo Molnar
2012-01-18 17:56       ` Steven Rostedt
2012-01-22 22:59         ` Rusty Russell
2012-01-26  2:41           ` [RFC][PATCH] tracing/module: Move tracepoint out of module.h Steven Rostedt
2012-01-26  2:45             ` Steven Rostedt
2012-01-26 10:28             ` Ingo Molnar
2012-01-26 13:52               ` Steven Rostedt
2012-01-26 13:55                 ` Ingo Molnar
2012-01-26 14:04                   ` Steven Rostedt
2012-01-26 14:07                     ` Steven Rostedt
2012-01-26 14:36                     ` Steven Rostedt
2012-01-26 18:39                       ` Ingo Molnar
2012-01-27  3:02                         ` Rusty Russell
2012-01-30 11:52                           ` Steven Rostedt
2012-01-30 17:28                             ` Steven Rostedt
2012-01-31  3:58                             ` Rusty Russell
2012-01-31 12:20                               ` Ingo Molnar [this message]
2012-01-31 12:50                                 ` Steven Rostedt
2012-02-01  6:48                                   ` Rusty Russell
2012-02-01 13:27                                     ` Steven Rostedt
2012-02-01 13:49                                     ` Ingo Molnar
2012-02-01 14:25                                       ` Steven Rostedt
2012-03-29  4:22                                     ` Eric Dumazet
2012-03-29  5:24                                       ` Rusty Russell
2012-02-01  1:10                                 ` Rusty Russell
2012-02-01  7:09                                   ` Ingo Molnar
2012-01-30  6:40                       ` Li Zefan
2012-02-17 13:46       ` [tip:perf/core] tracing/softirq: Move __raise_softirq_irqoff() out of header tip-bot for Steven Rostedt

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