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
next prev parent 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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