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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Jiri Olsa <jolsa@redhat.com>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Jan Stancek <jstancek@redhat.com>
Subject: Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage!
Date: Tue, 22 Nov 2016 00:19:25 -0800	[thread overview]
Message-ID: <20161122081925.GB3612@linux.vnet.ibm.com> (raw)
In-Reply-To: <20161121204445.GX26852@two.firstfloor.org>

On Mon, Nov 21, 2016 at 12:44:45PM -0800, Andi Kleen wrote:
> > > http://halobates.de/tracepoint-trace
> > 
> > There's a lot of push and pop regs due to function calling. There's
> > places that inlines can still improve things, and perhaps even some
> > likely unlikelys well placed.
> 
> Assuming you avoid all the push/pop and all the call/ret this would only be
> ~25% of the total instructions. There is just far too much logic and
> computation in there.
> 
> % awk ' { print $5 } '  tracepoint-trace | sort | uniq -c | sort -rn
>     222 mov
>      57 push
>      57 pop
>      35 test
>      34 cmp
>      32 and
>      28 jz
>      25 jnz
>      21 ret
>      20 call
>      16 lea
>      11 add

Hmmm...  It does indeed look like some performance analysis would be good...

							Thanx, Paul

  reply	other threads:[~2016-11-22  8:19 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-21  0:53 [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Jiri Olsa
2016-11-21  9:02 ` Paul E. McKenney
2016-11-21  9:43   ` Peter Zijlstra
2016-11-21 11:00     ` Paul E. McKenney
2016-11-21  9:28 ` Peter Zijlstra
2016-11-21  9:34   ` Jiri Olsa
2016-11-21  9:42     ` Peter Zijlstra
2016-11-21 11:22       ` Jiri Olsa
2016-11-21 11:31         ` Peter Zijlstra
2016-11-21 12:49           ` Jiri Olsa
2016-11-21 12:58     ` Peter Zijlstra
2016-11-21 14:15       ` Steven Rostedt
2016-11-21 14:37         ` Peter Zijlstra
2016-11-21 15:35           ` Borislav Petkov
2016-11-21 15:41             ` Peter Zijlstra
2016-11-21 16:06               ` Borislav Petkov
2016-11-29 13:16                 ` Borislav Petkov
2016-11-29 13:59                   ` Thomas Gleixner
2016-11-30  8:48                     ` Borislav Petkov
2016-11-30  8:54                       ` Thomas Gleixner
2016-11-30  9:07                         ` Borislav Petkov
2016-11-30  9:14                           ` Thomas Gleixner
2016-11-29 14:04                   ` Jiri Olsa
2016-11-21 14:20       ` Steven Rostedt
2016-11-21 17:06   ` Andi Kleen
2016-11-21 17:18     ` Peter Zijlstra
2016-11-21 17:45       ` Andi Kleen
2016-11-21 18:01         ` Steven Rostedt
2016-11-21 18:06           ` Andi Kleen
2016-11-21 18:22             ` Steven Rostedt
2016-11-21 18:37               ` Andi Kleen
2016-11-21 19:06                 ` Steven Rostedt
2016-11-21 19:15                 ` Steven Rostedt
2016-11-21 20:44                   ` Andi Kleen
2016-11-22  8:19                     ` Paul E. McKenney [this message]
2016-11-22 14:39                 ` Steven Rostedt
2016-11-22 19:05                   ` Andi Kleen
2016-11-24  2:06                 ` Steven Rostedt
2016-11-28 21:48                   ` Andi Kleen
2016-11-28 22:46                     ` Steven Rostedt
2016-11-28 23:10                       ` Andi Kleen
2016-11-21 17:55       ` Steven Rostedt
2016-11-21 18:24         ` Steven Rostedt
2016-11-21 20:12           ` Paul E. McKenney
2017-02-23 12:24   ` Jiri Olsa
2017-02-23 17:11     ` Andi Kleen
2017-02-23 17:28     ` Peter Zijlstra
2017-02-23 17:56       ` Borislav Petkov

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