Re: [PATCH] memblock, numa: Binary search node id

[Russ Anderson]

On Fri, Aug 16, 2013 at 12:15:21PM -0700, Yinghai Lu wrote:
> On Fri, Aug 16, 2013 at 12:01 PM, Russ Anderson <rja@xxxxxxx> wrote:
> > On Thu, Aug 15, 2013 at 01:43:48PM -0700, Andrew Morton wrote:
> >> On Wed, 14 Aug 2013 22:46:29 -0700 Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> >>
> >> > Current early_pfn_to_nid() on arch that support memblock go
> >> > over memblock.memory one by one, so will take too many try
> >> > near the end.
> >> >
> >> > We can use existing memblock_search to find the node id for
> >> > given pfn, that could save some time on bigger system that
> >> > have many entries memblock.memory array.
> >>
> >> Looks nice.  I wonder how much difference it makes.
> >
> > Here are the timing differences for several machines.
> > In each case with the patch less time was spent in __early_pfn_to_nid().
> >
> >
> >                         3.11-rc5        with patch      difference (%)
> >                         --------        ----------      --------------
> > UV1: 256 nodes  9TB:     411.66          402.47         -9.19 (2.23%)
> > UV2: 255 nodes 16TB:    1141.02         1138.12         -2.90 (0.25%)
> > UV2:  64 nodes  2TB:     128.15          126.53         -1.62 (1.26%)
> > UV2:  32 nodes  2TB:     121.87          121.07         -0.80 (0.66%)
> >                         Time in seconds.
> >
> 
> Thanks.
> 
> 9T one have more entries in memblock.memory?

Yes.  It is older hardware with smaller DIMMs and more of them.

-- 
Russ Anderson, OS RAS/Partitioning Project Lead  
SGI - Silicon Graphics Inc          rja@xxxxxxx
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