Re: [RFC] NUMA futex hashing

Nick Piggin
2006-08-08T16:34:57Z

Eric Dumazet wrote:

> We certainly can. But if you insist of using mmap sem at all, then we have a
> problem.
>
> rbtree would not reduce cacheline bouncing, so :
>
> We could use a hashtable (allocated on demand) of size N, N depending on
> NR_CPUS for example. each chain protected by a private spinlock. If N is well
> chosen, we might reduce lock cacheline bouncing. (different threads fighting
> on different private futexes would have a good chance to get different
> cachelines in this hashtable)

See other mail. We already have a hash table ;)

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SUSE Labs, Novell Inc.
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