Messages in this thread | | | From | Kevin Puetz <> | Subject | RE: Industry db benchmark result on recent 2.6 kernels | Date | Sun, 03 Apr 2005 20:40:12 -0500 |
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Linus Torvalds wrote:
> > > On Fri, 1 Apr 2005, Chen, Kenneth W wrote: >> >> Paul, you definitely want to check this out on your large numa box. I >> booted a kernel with this patch on a 32-way numa box and it took a long >> .... time to produce the cost matrix. > > Is there anything fundamentally wrong with the notion of just initializing > the cost matrix to something that isn't completely wrong at bootup, and > just lettign user space fill it in?
Wouldn't getting rescheduled (and thus having another program trash the cache on you) really mess up the data collection though? I suppose by spawning off threads, each with a fixed affinity and SCHED_FIFO one could hang onto the CPU to collect the data. But then it's not (a lot) different than doing it in-kernel.
> Then you couple that with a program that can do so automatically (ie > move the in-kernel heuristics into user-land), and something that can > re-load it on demand.
This part seems sensible though :-)
> Voila - you have something potentially expensive that you run once, and > then you have a matrix that can be edited by the sysadmin later and just > re-loaded at each boot.. That sounds pretty optimal, especially in the > sense that it allows the sysadmin to tweak things depending on the use of > the box is he really wants to. > > Hmm? Or am I just totally on crack? > > Linus
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