* William Lee Irwin III <[EMAIL PROTECTED]> wrote: > The performance relative to mutual exclusion is quantifiable and very > reproducible. [...]
yes, i dont doubt the results - my point is that it's not proven that the other, more read-friendly types of locking underperform rwlocks. Obviously spinlocks and rwlocks have the same cache-bounce properties, so rwlocks can outperform spinlocks if the read path overhead is higher than that of a bounce, and reads are dominant. But it's still a poor form of scalability. In fact, when the read path is really expensive (larger than say 10-20 usecs) an rwlock can produce the appearance of linear scalability, when compared to spinlocks. > As far as performance relative to RCU goes, I suspect cases where > write-side latency is important will arise for these. Other lockless > methods are probably more appropriate, and are more likely to dominate > rwlocks as expected. For instance, a reimplementation of the radix > trees for lockless insertion and traversal (c.f. lockless pagetable > patches for examples of how that's carried out) is plausible, where > RCU memory overhead in struct page is not. yeah. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/