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Re: Odd performance results

From Peter Zijlstra <peterz@infradead.org>
Newsgroups linux.kernel
Subject Re: Odd performance results
Date 2016-07-10 07:20 +0200
Message-ID <rTfjQ-4IO-5@gated-at.bofh.it> (permalink)
References <rTexs-4cA-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 10 July 2016 06:26:39 CEST, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
>Hello!
>
>So I ran a quick benchmark which showed stair-step results.  I
>immediately
>thought "Ah, this is due to CPU 0 and 1, 2 and 3, 4 and 5, and 6 and 7
>being threads in a core."  Then I thought "Wait, this is an x86!"
>Then I dumped out cpu*/topology/thread_siblings_list, getting the
>following:
>
>	cpu0/topology/thread_siblings_list: 0-1
>	cpu1/topology/thread_siblings_list: 0-1
>	cpu2/topology/thread_siblings_list: 2-3
>	cpu3/topology/thread_siblings_list: 2-3
>	cpu4/topology/thread_siblings_list: 4-5
>	cpu5/topology/thread_siblings_list: 4-5
>	cpu6/topology/thread_siblings_list: 6-7
>	cpu7/topology/thread_siblings_list: 6-7


I'm guessing this is an AMD bulldozer like machine?
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

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Thread

Odd performance results "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-07-10 06:30 +0200
  Re: Odd performance results Peter Zijlstra <peterz@infradead.org> - 2016-07-10 07:20 +0200
    Re: Odd performance results "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-07-10 16:50 +0200
      Re: Odd performance results Peter Zijlstra <peterz@infradead.org> - 2016-07-12 17:00 +0200
        Re: Odd performance results "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-07-12 17:10 +0200
          Re: Odd performance results "H. Peter Anvin" <hpa@zytor.com> - 2016-07-12 20:00 +0200
            Re: Odd performance results "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-07-12 20:30 +0200
            Re: Odd performance results Peter Zijlstra <peterz@infradead.org> - 2016-07-12 21:00 +0200
              Re: [CRM114spam]: Re: Odd performance results "Dr. David Alan Gilbert" <dave@treblig.org> - 2016-07-12 21:40 +0200
                Re: [CRM114spam]: Re: Odd performance results "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-07-12 22:10 +0200
                Re: [CRM114spam]: Re: Odd performance results Ingo Molnar <mingo@kernel.org> - 2016-07-13 09:30 +0200
              Re: Odd performance results Ingo Molnar <mingo@kernel.org> - 2016-07-13 09:20 +0200
                Re: Odd performance results Henrique de Moraes Holschuh <hmh@hmh.eng.br> - 2016-07-13 14:40 +0200
                Re: Odd performance results Peter Zijlstra <peterz@infradead.org> - 2016-07-13 14:40 +0200
                Re: Odd performance results "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-07-13 16:10 +0200

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