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Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage!

From "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Newsgroups linux.kernel
Subject Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage!
Date 2016-11-22 09:20 +0100
Message-ID <sGet4-4Fo-13@gated-at.bofh.it> (permalink)
References (5 earlier) <sG1ct-4DY-21@gated-at.bofh.it> <sG1vP-4LN-1@gated-at.bofh.it> <sG1Fw-4P0-21@gated-at.bofh.it> <sG2ii-5ho-3@gated-at.bofh.it> <sG3Hj-64o-7@gated-at.bofh.it>
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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

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Thread

[BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Jiri Olsa <jolsa@redhat.com> - 2016-11-21 02:00 +0100
  Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-21 10:10 +0100
    Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Peter Zijlstra <peterz@infradead.org> - 2016-11-21 10:50 +0100
      Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-21 12:10 +0100
  Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Peter Zijlstra <peterz@infradead.org> - 2016-11-21 10:30 +0100
    Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Jiri Olsa <jolsa@redhat.com> - 2016-11-21 10:40 +0100
      Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Peter Zijlstra <peterz@infradead.org> - 2016-11-21 10:50 +0100
        Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Jiri Olsa <jolsa@redhat.com> - 2016-11-21 12:30 +0100
          Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Peter Zijlstra <peterz@infradead.org> - 2016-11-21 12:40 +0100
            Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Jiri Olsa <jolsa@redhat.com> - 2016-11-21 13:50 +0100
      Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Peter Zijlstra <peterz@infradead.org> - 2016-11-21 14:00 +0100
        Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-21 15:30 +0100
          Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Peter Zijlstra <peterz@infradead.org> - 2016-11-21 15:40 +0100
            Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Borislav Petkov <bp@alien8.de> - 2016-11-21 16:40 +0100
              Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Peter Zijlstra <peterz@infradead.org> - 2016-11-21 16:50 +0100
                Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Borislav Petkov <bp@alien8.de> - 2016-11-21 17:10 +0100
        Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-21 15:30 +0100
    Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Andi Kleen <andi@firstfloor.org> - 2016-11-21 18:10 +0100
      Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Peter Zijlstra <peterz@infradead.org> - 2016-11-21 18:20 +0100
        Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Andi Kleen <andi@firstfloor.org> - 2016-11-21 18:50 +0100
          Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Andi Kleen <andi@firstfloor.org> - 2016-11-21 19:10 +0100
            Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-21 19:30 +0100
              Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Andi Kleen <andi@firstfloor.org> - 2016-11-21 19:40 +0100
                Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-21 20:10 +0100
                Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-21 20:20 +0100
                Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Andi Kleen <andi@firstfloor.org> - 2016-11-21 21:50 +0100
                Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-22 09:20 +0100
                Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-22 15:40 +0100
                Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Andi Kleen <andi@firstfloor.org> - 2016-11-22 20:10 +0100
                Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-24 03:10 +0100
          Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-21 19:10 +0100
        Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-21 19:00 +0100
          Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! Steven Rostedt <rostedt@goodmis.org> - 2016-11-21 19:30 +0100
            Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage! "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-21 21:20 +0100

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