Messages in this thread | | | Subject | Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to 3.6-rc5 on AMD chipsets - bisected | From | Mike Galbraith <> | Date | Thu, 27 Sep 2012 15:38:20 +0200 |
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On Thu, 2012-09-27 at 12:20 +0200, Borislav Petkov wrote: > On Thu, Sep 27, 2012 at 12:17:22AM -0700, david@lang.hm wrote: > > It seems to me that trying to figure out if you are going to > > overload the L2 is an impossible task, so just assume that it will > > all fit, and the worst case is you have one balancing cycle where > > you can't do as much work and then the normal balancing will kick in > > and move something anyway. > > Right, and this implies that when the load balancer runs, it will > definitely move the task away from the L2. But what do I do in the cases > where the two tasks don't overload the L2 and it is actually beneficial > to keep them there? How does the load balancer know that?
It doesn't, but it has task_hot(). A preempted buddy may be pulled, but the next wakeup will try to bring buddies back together.
-Mike
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