> Why would it make sense here? There may be cases were switching all read locks to unfair may make concerete workloads slower.
The effect is very visible in (non kernel) lock micro benchmarks, especially with HyperThreading. With very high contention or long enough critical sections the ordered lock usually wins, but it loses with lower contention. Unfortunately the "small critical section" case (even though it's really bad for any contended lock) is reasonably common :-/ [IMHO all of these should be fixed or "batched" somehow, but in some cases it is quite hard] However ordered locks definitely have more consistent performance. If prioritizing consistency over potential slow down in some cases is fine only having the ordered option is ok. -Andi -- 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/
