Re: [PATCH 0/6] xen,xend,tools: Add NUMA support to Xen

[Ryan Harper <ryanh@us.ibm.com>]

* Tristan Gingold <Tristan.Gingold@bull.net> [2006-08-01 02:43]:
> Le Lundi 31 Juillet 2006 21:09, Ryan Harper a écrit :
> > I've respun the NUMA patches against 10874 and I'm re-submitting them
> > with the optimizations mentioned [1]previously on the list.  There was a
> > request to see the overhead on non-numa/single-node machines.  I've
> > re-run those benchmarks (ballooning up from small mem to multi-gig) as
> > well as timing the initially domain increase_reservation time to gauge
> > the overhead when allocating from the heap.
> Hi,
> 
> I am trying to use your patch on ia64.

Thanks for testing these out on ia64.

> 
> In asm-x86/topology.h, you wrote:
> 
> extern unsigned int cpu_to_node[];
> extern cpumask_t     node_to_cpumask[];
> 
> #define cpu_to_node(cpu)		(cpu_to_node[cpu])
> #define parent_node(node)		(node)
> #define node_to_first_cpu(node)  (__ffs(node_to_cpumask[node]))
> #define node_to_cpumask(node)    (node_to_cpumask[node])
> 
> I think cpu_to_node and node_to_cpumask must be either a variable or a macro, 
> but not both! (ia64 defines cpu_to_node as a macro).

I'm not sure about this, but the definition of both the variable and
macro come from Linux, for example in

linux/include/asm-x86_64/topology.h

extern unsigned char cpu_to_node[];
extern cpumask_t     node_to_cpumask[];

#ifdef CONFIG_ACPI_NUMA
extern int __node_distance(int, int);
#define node_distance(a,b) __node_distance(a,b)
/* #else fallback version */
#endif

#define cpu_to_node(cpu)      (cpu_to_node[cpu])
#define parent_node(node)     (node)
#define node_to_first_cpu(node)  (first_cpu(node_to_cpumask[node]))
#define node_to_cpumask(node)    (node_to_cpumask[node])

AFAIK, this isn't an issue.

-- 
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253   T/L: 678-9253
ryanh@us.ibm.com