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From: Andi Kleen <andi@firstfloor.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andi Kleen <andi@firstfloor.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Jiri Olsa <jolsa@redhat.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.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: Mon, 21 Nov 2016 12:44:45 -0800	[thread overview]
Message-ID: <20161121204445.GX26852@two.firstfloor.org> (raw)
In-Reply-To: <20161121141517.31936dbe@gandalf.local.home>

> > 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

-Andi

  reply	other threads:[~2016-11-21 20:44 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 [this message]
2016-11-22  8:19                     ` Paul E. McKenney
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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