Messages in this thread | | | Date | Mon, 20 Feb 2006 16:09:24 -0800 | From | Ravikiran G Thirumalai <> | Subject | Re: [patch] Cache align futex hash buckets |
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On Mon, Feb 20, 2006 at 03:34:19PM -0800, Andrew Morton wrote: > Andrew Morton <akpm@osdl.org> wrote: > > > > > @@ -100,9 +100,10 @@ struct futex_q { > > > struct futex_hash_bucket { > > > spinlock_t lock; > > > struct list_head chain; > > > -}; > > > +} ____cacheline_internodealigned_in_smp; > > > > > > -static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS]; > > > +static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS] > > > + __cacheline_aligned_in_smp; > > > > > > > How much memory does that thing end up consuming? > > I think a megabyte?
On most machines it would be 256 * 128 = 32k. or 16k on arches with 64B cachelines. This looked like a simpler solution for spinlocks falling on the same cacheline. So is 16/32k unreasonable?
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