From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Li Zefan <lizf@cn.fujitsu.com>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 1/7] ring-buffer: remove unneeded conditional in rb_reserve_next
Date: Thu, 7 May 2009 10:23:03 +0200 [thread overview]
Message-ID: <20090507082303.GE12285@elte.hu> (raw)
In-Reply-To: <20090507031433.562803300@goodmis.org>
* Steven Rostedt <rostedt@goodmis.org> wrote:
> From: Steven Rostedt <srostedt@redhat.com>
>
> The code in __rb_reserve_next checks on page overflow if it is the
> original commiter and then resets the page back to the original
> setting. Although this is fine, and the code is correct, it is
> a bit fragil. Some experimental work I did breaks it easily.
s/fragil/fragile
> The better and more robust solution is to have all commiters that
> overflow the page, simply subtract what they added.
>
> [ Impact: more robust ring buffer account management ]
it's a bit faster too (eliminates two branches) - so a
micro-optimization as well.
Ingo
next prev parent reply other threads:[~2009-05-07 8:23 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-07 3:13 [PATCH 0/7] [GIT PULL] tracing/ring-buffer: more updates for tip Steven Rostedt
2009-05-07 3:13 ` [PATCH 1/7] ring-buffer: remove unneeded conditional in rb_reserve_next Steven Rostedt
2009-05-07 8:23 ` Ingo Molnar [this message]
2009-05-07 3:13 ` [PATCH 2/7] ring-buffer: check for failed allocation in ring buffer benchmark Steven Rostedt
2009-05-07 3:13 ` [PATCH 3/7] ring-buffer: make moving the tail page a separate function Steven Rostedt
2009-05-07 8:27 ` Ingo Molnar
2009-05-07 13:26 ` Steven Rostedt
2009-05-07 13:56 ` Ingo Molnar
2009-05-07 3:13 ` [PATCH 4/7] ring-buffer: change test to be more latency friendly Steven Rostedt
2009-05-07 8:31 ` Ingo Molnar
2009-05-07 8:34 ` Ingo Molnar
2009-05-07 13:51 ` Steven Rostedt
2009-05-07 3:13 ` [PATCH 5/7] tracing: update sample with TRACE_INCLUDE_FILE Steven Rostedt
2009-05-07 3:13 ` [PATCH 6/7] tracing: reset ring buffer when removing modules with events Steven Rostedt
2009-05-07 3:51 ` Li Zefan
2009-05-07 16:24 ` Frederic Weisbecker
2009-05-07 3:13 ` [PATCH 7/7] tracing: add hierarchical enabling of events Steven Rostedt
2009-05-07 3:51 ` Li Zefan
2009-05-07 13:21 ` Steven Rostedt
2009-05-08 1:11 ` Li Zefan
2009-05-08 1:23 ` Steven Rostedt
2009-05-08 1:24 ` Steven Rostedt
2009-05-07 16:28 ` Frederic Weisbecker
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