On Sat, Sep 28, 2013 at 12:33:36PM -0700, Linus Torvalds wrote: > The old rwlock's really have been a disappointment - they are slower > than spinlocks, and seldom/never end up scaling any better. Their > main advantage was literally the irq behavior - allowing readers to > happen without the expense of worrying about irq's.
So in part that is fundamental to the whole rw-spinlock concept. Typically lock hold times should be short for spinlock type locks and if your hold times are short, the lock acquisition times are significant. And a read acquisition is still a RMW operation on the lock, thus read locks are still entirely bound by the cacheline transfer of the lock itself. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
