Messages in this thread | | | Date | Thu, 04 Sep 2003 13:38:52 +1000 | From | Nick Piggin <> | Subject | Re: Scaling noise |
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Larry McVoy wrote:
>On Wed, Sep 03, 2003 at 06:12:53PM -0700, William Lee Irwin III wrote: > >>On Wed, Sep 03, 2003 at 02:51:35PM -0700, William Lee Irwin III wrote: >> >>>>This is only truly feasible when the nodes are homogeneous. They will >>>>not be as there will be physical locality (esp. bits like device >>>>proximity) concerns. >>>> >>On Wed, Sep 03, 2003 at 05:58:22PM -0700, Larry McVoy wrote: >> >>>Huh? The nodes are homogeneous. Devices are either local or proxied. >>> >>Virtualized devices are backed by real devices at some level, so the >>distance from the node's physical location to the device's then matters. >> > >Go read what I've written about this. There is no sharing, devices are >local or remote. You share in the page cache only, if you want fast access >to a device you ask it to put the data in memory and you map it. It's >absolutely as fast as an SMP. With no locking. >
There is probably more to it - I'm just an interested bystander - but how much locking does this case incur with a single kernel system? And what happens if more than one node wants to access the device? Through a filesystem?
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