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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jason Baron <jbaron@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Koki Sanagi <sanagi.koki@jp.fujitsu.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@elte.hu>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	nhorman@tuxdriver.com, scott.a.mcmillan@intel.com,
	laijs@cn.fujitsu.com, LKML <linux-kernel@vger.kernel.org>,
	eric.dumazet@gmail.com, kaneshige.kenji@jp.fujitsu.com,
	David Miller <davem@davemloft.net>,
	izumi.taku@jp.fujitsu.com, kosaki.motohiro@jp.fujitsu.com,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	"Luck, Tony" <tony.luck@intel.com>
Subject: Re: [PATCH] tracing: Cleanup the convoluted softirq tracepoints
Date: Mon, 25 Oct 2010 18:01:05 -0400	[thread overview]
Message-ID: <20101025220105.GB26517@Krystal> (raw)
In-Reply-To: <4CC5FC99.8090203@zytor.com>

* H. Peter Anvin (hpa@zytor.com) wrote:
> On 10/20/2010 08:27 AM, Jason Baron wrote:
> > 
> > sure. The idea of the 'jmp 0' was simply to be an lcd for x86, if
> > there's a better lcd for x86, I'll update it. But note, that since the
> > 'jmp 0' is patched to a better nop at boot, we wouldn't see much gain.
> > And in the boot path we are using 'text_poke_early()', so avoiding that
> > isn't going to improve things much.
> > 
> 
> It's still a completely unnecessary waste of startup time some
> potentially significant fraction of the time.  Startup time matters,
> especially as the number of tracepoints grow.

We're still waiting for input for the best single-5-byte-instruction nop that
will work on all x86 variants. Please note that the GENERIC_NOP5 is actually two
instructions one next to each other, which is not appropriate here.

Thanks,

Mathieu

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

  reply	other threads:[~2010-10-25 22:01 UTC|newest]

Thread overview: 93+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-23  9:41 [PATCH v4 0/5] netdev: show a process of packets Koki Sanagi
2010-08-23  9:42 ` [PATCH v4 1/5] irq: add tracepoint to softirq_raise Koki Sanagi
2010-09-03 15:29   ` Frederic Weisbecker
2010-09-03 15:39     ` Steven Rostedt
2010-09-03 15:42       ` Frederic Weisbecker
2010-09-03 15:43     ` Steven Rostedt
2010-09-03 15:50       ` Frederic Weisbecker
2010-09-06  1:46         ` Koki Sanagi
2010-09-08  8:33   ` [tip:perf/core] irq: Add " tip-bot for Lai Jiangshan
2010-09-08 11:25     ` [sparc build bug] " Ingo Molnar
2010-09-08 12:26       ` [PATCH] irq: Fix circular headers dependency Frederic Weisbecker
2010-09-09 19:54         ` [tip:perf/core] " tip-bot for Frederic Weisbecker
2010-10-18  9:44       ` [sparc build bug] Re: [tip:perf/core] irq: Add tracepoint to softirq_raise Peter Zijlstra
2010-10-18 10:11         ` Peter Zijlstra
2010-10-18 10:26           ` Heiko Carstens
2010-10-18 10:48         ` Peter Zijlstra
2010-10-19 10:58           ` Koki Sanagi
2010-10-19 11:25             ` Peter Zijlstra
2010-10-19 13:00             ` [PATCH] tracing: Cleanup the convoluted softirq tracepoints Thomas Gleixner
2010-10-19 13:08               ` Peter Zijlstra
2010-10-19 13:22               ` Mathieu Desnoyers
2010-10-19 13:41                 ` Thomas Gleixner
2010-10-19 13:54                   ` Steven Rostedt
2010-10-19 14:07                     ` Thomas Gleixner
2010-10-19 14:28                       ` Mathieu Desnoyers
2010-10-19 19:49                         ` Thomas Gleixner
2010-10-19 20:55                           ` Steven Rostedt
2010-10-19 21:07                             ` Thomas Gleixner
2010-10-19 21:23                               ` Steven Rostedt
2010-10-19 21:48                                 ` H. Peter Anvin
2010-10-19 22:23                                   ` Steven Rostedt
2010-10-19 22:26                                     ` H. Peter Anvin
2010-10-19 22:27                                     ` Peter Zijlstra
2010-10-19 23:39                                       ` H. Peter Anvin
2010-10-19 23:45                                         ` Steven Rostedt
2010-10-20  0:43                                         ` Jason Baron
2010-10-19 22:41                                   ` Mathieu Desnoyers
2010-10-19 22:49                                     ` H. Peter Anvin
2010-10-19 23:05                                       ` Steven Rostedt
2010-10-19 23:09                                         ` H. Peter Anvin
2010-10-20 15:27                                         ` Jason Baron
2010-10-20 15:41                                           ` Mathieu Desnoyers
2010-10-25 21:54                                           ` H. Peter Anvin
2010-10-25 22:01                                             ` Mathieu Desnoyers [this message]
2010-10-25 22:12                                               ` H. Peter Anvin
2010-10-25 22:19                                                 ` H. Peter Anvin
2010-10-25 22:55                                                 ` Mathieu Desnoyers
2010-10-26  0:39                                                   ` Steven Rostedt
2010-10-26  1:14                                                     ` Mathieu Desnoyers
2010-10-19 22:04                                 ` Thomas Gleixner
2010-10-19 22:33                                   ` Steven Rostedt
2010-10-21 16:18                                     ` Thomas Gleixner
2010-10-21 17:05                                       ` Steven Rostedt
2010-10-21 19:56                                         ` Thomas Gleixner
2010-10-25 22:31                                           ` H. Peter Anvin
2010-10-19 21:45                             ` Thomas Gleixner
2010-10-19 22:14                               ` Steven Rostedt
2010-10-19 21:16                           ` David Daney
2010-10-19 21:32                             ` Jason Baron
2010-10-19 21:38                               ` David Daney
2010-10-19 21:47                             ` Steven Rostedt
2010-10-19 21:28                           ` Jason Baron
2010-10-19 21:55                             ` Thomas Gleixner
2010-10-19 22:17                               ` Thomas Gleixner
2010-10-20  1:36                                 ` Steven Rostedt
2010-10-20  1:52                                   ` Jason Baron
2010-10-25 22:32                                     ` H. Peter Anvin
2010-10-19 22:38                               ` Jason Baron
2010-10-19 22:44                                 ` H. Peter Anvin
2010-10-19 22:56                                   ` Steven Rostedt
2010-10-19 22:57                                     ` H. Peter Anvin
2010-10-19 14:46                       ` Steven Rostedt
2010-10-19 14:00                   ` Mathieu Desnoyers
2010-10-21 14:52               ` [tip:perf/core] " tip-bot for Thomas Gleixner
2010-08-23  9:43 ` [PATCH v4 2/5] napi: convert trace_napi_poll to TRACE_EVENT Koki Sanagi
2010-08-24  3:52   ` David Miller
2010-09-08  8:34   ` [tip:perf/core] napi: Convert " tip-bot for Neil Horman
2010-08-23  9:45 ` [PATCH v4 3/5] netdev: add tracepoints to netdev layer Koki Sanagi
2010-08-24  3:53   ` David Miller
2010-09-08  8:34   ` [tip:perf/core] netdev: Add " tip-bot for Koki Sanagi
2010-08-23  9:46 ` [PATCH v4 4/5] skb: add tracepoints to freeing skb Koki Sanagi
2010-08-24  3:53   ` David Miller
2010-09-08  8:35   ` [tip:perf/core] skb: Add " tip-bot for Koki Sanagi
2010-08-23  9:47 ` [PATCH v4 5/5] perf:add a script shows a process of packet Koki Sanagi
2010-08-24  3:53   ` David Miller
2010-09-07 16:57   ` Frederic Weisbecker
2010-09-08  8:35   ` [tip:perf/core] perf: Add a script to show packets processing tip-bot for Koki Sanagi
2010-08-30 23:50 ` [PATCH v4 0/5] netdev: show a process of packets Steven Rostedt
2010-09-03  2:10   ` Koki Sanagi
2010-09-03  2:17     ` David Miller
2010-09-03  2:55       ` Koki Sanagi
2010-09-03  4:46         ` Frederic Weisbecker
2010-09-03  5:12           ` Koki Sanagi

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