On Mar 5, 7:11 pm, Toru Maesaka <[email protected]> wrote:


> As for the global stats_lock, I think its safe to assume that most of
> the operations are write related so read-write locking is definitely
> not the answer here. I think Facebook was dead-on with their solution
> on scaling this area up (use scoreboarding per thread basis and
> aggregate the results when needed).

  Trond's already done that per-thread work and pushed it, so it's
ready in that branch.  He's currently working on adding more locks to
a single hash table (a la java's ConcurrentHashMap).

  The read/write stuff sounds pretty interesting, though.

> To begin with I'm going to only experiment with using rw-locking for
> cache_lock. I'll test the performance with libmemcached's memslap and
> let you all know how it turned out... hopefully in not so distant
> future.

  Great.  Trond still doing some work to reduce contention, that might
be an alternative approach.  I think he was pretty far along with that
work, though.  The results would be useful for general mutex strategy
advice.

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