Messages in this thread | | | Date | Fri, 19 Mar 2004 10:50:47 +0100 | From | Ingo Molnar <> | Subject | Re: [BENCHMARKS] 2.6.4 vs 2.6.4-mm1 |
| |
* Nick Piggin <piggin@cyberone.com.au> wrote:
> volanomark (MPS): > This one starts getting huge mmap_sem contention at 150+ coming > from futexes. Don't know what is taking the mmap_sem for writing. > Maybe just brk or mmap.
are you sure it's down_write() contention? down_read() can create contention just as much, simply due to the fact that hundreds of threads and a dozen CPUs are pounding in on the same poor lock.
i do think there should be a rw-semaphore variant that is per-cpu for the read path. (This would also fix the 4:4 threading overhead.)
Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |