On Mon, Jun 27, 2005 at 12:42:44PM -0700, Chen, Kenneth W wrote: > Christoph Lameter wrote on Monday, June 27, 2005 12:23 PM > > On Mon, 27 Jun 2005, Chen, Kenneth W wrote: > > > I don't recall seeing tree_lock to be a problem for DSS workload either. > > > > I have seen the tree_lock being a problem a number of times with large > > scale NUMA type workloads. > > I totally agree! My earlier posts are strictly referring to industry > standard db workloads (OLTP, DSS). I'm not saying it's not a problem > for everyone :-) Obviously you just outlined a few ....
I'm a bit late to the party here (was gone on vacation), but I do have profiles from DSS workloads using page-cache rather than O_DIRECT and I do see spin_lock_irq() in the profiles which I'm pretty certain are locks spinning for access to the radix_tree. I'll talk about it a bit more up in Ottawa but here's the top 5 on my profile (sorry don't have the number of ticks at the momement): 1. dedicated_idle (waiting for I/O) 2. __copy_tofrom_user 3. radix_tree_delete 4. _spin_lock_irq 5. __find_get_block So, yes, if the page-cache is used in a DSS workload then one will see the tree-lock. BTW, this was on a PPC64 machine w/ a fairly small NUMA factor. Sonny - 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/