Re: SLUB: Support for statistics to help analyze allocator behavior

[Eric Dumazet]

Pekka J Enberg a écrit :
> Hi Christoph,
>
> On Mon, 4 Feb 2008, Christoph Lameter wrote:
> > The statistics provided here allow the monitoring of allocator behavior
> > at the cost of some (minimal) loss of performance. Counters are placed in
> > SLUB's per cpu data structure that is already written to by other code.
>
> Looks good but I am wondering if we want to make the statistics per-CPU so 
> that we can see the kmalloc/kfree ping-pong of, for example, hackbench 
> better?

AFAIK Christoph patch already have percpu statistics :)


+#define STAT_ATTR(si, text) 					\
+static ssize_t text##_show(struct kmem_cache *s, char *buf)	\
+{								\
+	unsigned long sum  = 0;					\
+	int cpu;						\
+								\
+	for_each_online_cpu(cpu)				\
+		sum += get_cpu_slab(s, cpu)->stat[si];		\
+	return sprintf(buf, "%lu\n", sum);			\
+}								\

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