On Wed, Oct 22, 2014 at 02:09:35PM -0400, Joe Mario wrote: > >Yes, kernel memory is directly addresses, you basically have a static > >address->node mapping, it never changes. > > For kernel addresses, is there a reason not to have it available in perf, > especially when that knowledge is important to understanding a numa-related > slowdown?
Dunno why that isn't exposed in sysfs. > In our case, when we booted with one configuration, AIM ran fine. When we > booted another way, AIM's performance dropped 50%. It was all due to the > dentry > lock being located on a different (now remote) numa node. > > We used your dmesg approach to track down the home node in an attempt to > understand > what was different between the two boots. But the problem would have been > obvious > if perf simply listed the home node info. Or if you'd used more counters that track the node interconnect traffic ;-) There are a few simple ones that count local/remote type things (offcore), but using the uncore counters you can track way more. -- 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/
