1. 14 Oct, 2009 2 commits
    • Peter Zijlstra's avatar
      sched: Do less agressive buddy clearing · 92f6a5e3
      Peter Zijlstra authored
      Yanmin reported a hackbench regression due to:
      
       > commit de69a80b
       > Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
       > Date:   Thu Sep 17 09:01:20 2009 +0200
       >
       >     sched: Stop buddies from hogging the system
      
      I really liked de69a80b, and it affecting hackbench shows I wasn't
      crazy ;-)
      
      So hackbench is a multi-cast, with one sender spraying multiple
      receivers, who in their turn don't spray back.
      
      This would be exactly the scenario that patch 'cures'. Previously
      we would not clear the last buddy after running the next task,
      allowing the sender to get back to work sooner than it otherwise
      ought to have been, increasing latencies for other tasks.
      
      Now, since those receivers don't poke back, they don't enforce the
      buddy relation, which means there's nothing to re-elect the sender.
      
      Cure this by less agressively clearing the buddy stats. Only clear
      buddies when they were not chosen. It should still avoid a buddy
      sticking around long after its served its time.
      Reported-by: default avatar"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      CC: Mike Galbraith <efault@gmx.de>
      LKML-Reference: <1255084986.8802.46.camel@laptop>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      92f6a5e3
    • Peter Zijlstra's avatar
      sched: Disable SD_PREFER_LOCAL for MC/CPU domains · 799e2205
      Peter Zijlstra authored
      Yanmin reported that both tbench and hackbench were significantly
      hurt by trying to keep tasks local on these domains, esp on small
      cache machines.
      
      So disable it in order to promote spreading outside of the cache
      domains.
      Reported-by: default avatar"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      CC: Mike Galbraith <efault@gmx.de>
      LKML-Reference: <1255083400.8802.15.camel@laptop>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      799e2205
  2. 12 Oct, 2009 1 commit
  3. 09 Oct, 2009 2 commits
  4. 08 Oct, 2009 35 commits