Messages in this thread | | | Date | 16 Aug 2004 02:12:38 +0200 | Date | Mon, 16 Aug 2004 02:12:38 +0200 | From | Andi Kleen <> | Subject | Re: page fault fastpath: Increasing SMP scalability by introducing pte locks? |
| |
On Sun, Aug 15, 2004 at 04:55:57PM -0700, Christoph Lameter wrote: > On Mon, 16 Aug 2004, Andi Kleen wrote: > > > Christoph Lameter <clameter@sgi.com> writes: > > > > > On Sun, 15 Aug 2004, David S. Miller wrote: > > > > > >> > > >> Is the read lock in the VMA semaphore enough to let you do > > >> the pgd/pmd walking without the page_table_lock? > > >> I think it is, but just checking. > > > > > > That would be great.... May I change the page_table lock to > > > be a read write spinlock instead? > > > > That's probably not a good idea. r/w locks are extremly slow on > > some architectures. Including ia64. > > I was thinking about a read write spinlock not an readwrite > semaphore. Look at include/asm-ia64/spinlock.h.
I was also talking about rw spinlocks.
> The implementations are almost the same. Are you sure > about this?
Yes. Try the cat /proc/net/tcp test. It will take >100k read locks for the TCP listen hash table, and on bigger ppc64 and ia64 machines this can take nearly a second of system time.
-Andi - 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/
| |