From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
"H. Peter Anvin" <hpa@zytor.com>, Dave Jones <davej@redhat.com>,
Andi Kleen <ak@linux.intel.com>, acme <acme@ghostprotocols.net>
Subject: Re: [PATCH 1/5] ftrace: Synchronize variable setting with breakpoints
Date: Thu, 31 May 2012 16:40:33 -0400 [thread overview]
Message-ID: <1338496833.13348.432.camel@gandalf.stny.rr.com> (raw)
In-Reply-To: <1338496676.13348.430.camel@gandalf.stny.rr.com>
On Thu, 2012-05-31 at 16:37 -0400, Steven Rostedt wrote:
> On Thu, 2012-05-31 at 22:26 +0200, Peter Zijlstra wrote:
>
> > Right, but when you loose stop-machine you could simply do 30k
> > kmap_atomic/kunmap_atomic's consecutively since you're not holding
> > anybody up.
>
> It requires 3 IPIs per update too. Thus that's 90,000 IPIs you are
> blasting^Wsending to all CPUs.
>
Note, currently ftrace adds breakpoints to all locations, sends out the
IPIs, modifies the code, sends out the IPIs and then removes the
breakpoint, sends out the IPIs.
Just three IPIs for those 30,000 updates.
-- Steve
next prev parent reply other threads:[~2012-05-31 20:40 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-31 1:28 [PATCH 0/5] [GIT PULL] ftrace: Fix bug with function tracing and lockdep Steven Rostedt
2012-05-31 1:28 ` [PATCH 1/5] ftrace: Synchronize variable setting with breakpoints Steven Rostedt
2012-05-31 11:06 ` Peter Zijlstra
2012-05-31 14:08 ` Steven Rostedt
2012-05-31 15:16 ` Masami Hiramatsu
2012-05-31 15:29 ` Steven Rostedt
2012-05-31 17:28 ` Peter Zijlstra
2012-05-31 18:42 ` Steven Rostedt
2012-05-31 17:40 ` Peter Zijlstra
2012-05-31 17:44 ` Peter Zijlstra
2012-05-31 17:53 ` Steven Rostedt
2012-05-31 18:03 ` Peter Zijlstra
2012-05-31 18:50 ` Steven Rostedt
2012-05-31 19:06 ` Peter Zijlstra
2012-05-31 19:55 ` Mathieu Desnoyers
2012-05-31 20:10 ` Steven Rostedt
2012-05-31 20:26 ` Peter Zijlstra
2012-05-31 20:37 ` Steven Rostedt
2012-05-31 20:40 ` Steven Rostedt [this message]
2012-05-31 20:40 ` Peter Zijlstra
2012-05-31 20:49 ` Steven Rostedt
2012-06-01 4:53 ` Masami Hiramatsu
2012-06-01 11:37 ` Steven Rostedt
2012-06-01 12:52 ` Masami Hiramatsu
2012-06-01 0:45 ` Arnaldo Carvalho de Melo
2012-05-31 1:28 ` [PATCH 2/5] ftrace: Use breakpoint method to update ftrace caller Steven Rostedt
2012-05-31 11:18 ` Peter Zijlstra
2012-05-31 14:19 ` Steven Rostedt
2012-05-31 1:28 ` [PATCH 3/5] x86: Reset the debug_stack update counter Steven Rostedt
2012-05-31 19:19 ` H. Peter Anvin
2012-05-31 19:26 ` Steven Rostedt
2012-05-31 1:28 ` [PATCH 4/5] x86: Allow nesting of the debug stack IDT setting Steven Rostedt
2012-05-31 18:44 ` H. Peter Anvin
2012-05-31 18:58 ` H. Peter Anvin
2012-05-31 19:25 ` Steven Rostedt
2012-05-31 19:27 ` H. Peter Anvin
2012-05-31 20:00 ` Steven Rostedt
2012-05-31 20:17 ` H. Peter Anvin
2012-05-31 20:35 ` Steven Rostedt
2012-05-31 20:39 ` H. Peter Anvin
2012-05-31 20:56 ` Steven Rostedt
2012-05-31 21:09 ` H. Peter Anvin
2012-05-31 21:37 ` Steven Rostedt
2012-05-31 21:38 ` Steven Rostedt
2012-06-01 2:30 ` Steven Rostedt
2012-05-31 1:28 ` [PATCH 5/5] ftrace/x86: Do not change stacks in DEBUG when calling lockdep Steven Rostedt
2012-05-31 2:13 ` [PATCH 0/5] (for 3.5)[GIT PULL] ftrace: Fix bug with function tracing and lockdep Steven Rostedt
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