On Mon, Jan 18, 2010 at 5:31 PM, Jon Haslam <jonathan.has...@sun.com> wrote: > Hi Aubrey, > >> NUMAtop will focus on NUMA-related characteristic. Yes, the information is >> collected from memory-related hardware counters. Some of these counters >> are >> already supported in kcpc and libcpc, while some of them are not. We >> probably >> need to use Precise Event Based Sampling(PEBS), which seems not in the >> current >> solaris kernel and libcpc implementation. > > No, we don't support PEBS or any other sampling implementation > at the moment. The engineer who looks after cpc has some good > thoughts on a new sampling infrastructure but that's a whole > bunch of work. Not sure where he's up to with this but any > PEBS usage would need to fit in with that stream of work. Maybe > he's lurking here. > PEBS is important in our NUMAtop design to measure memory access latency for application. We will enhance kcpc to support PEBS and uncore events. If we can talk with CPC engineers and get their help, it will be great.
>> A good combined view is a part of our goal. It will show how effective the >> application is using the local memory. And we expect NUMAtop is able to >> help >> the user to figure out where is not effective and why. What's more, if >> NUMAtop >> can make a better memory placement strategy suggestion to the user, it >> would be >> great. >> >> We are trying to make NUMAtop to be a useful tool to diagnose NUMA-related >> memory >> placement problems and help to find solutions. We certainly need help from >> you >> experts, :) > > I'm sure sampling is probably what you need to get the job done > properly. However, don't forget about the DTrace cpc provider > as it may well be of use to you here. > We have considered CPC provider in our design to help user locate what function caused most of remote memory access, but this feature will not be in current implementation. Both NUMAtop and CPC provider need access performance counters, they can not program performance counter simultaneously. When customer identifys that his application may be impacted by remote memory access through NUMAtop. If he want to know the top functions which leads to remote memory access, NUMAtop can enter into CPC provider mode for sampling and provides such information. > Jon. > _______________________________________________ > perf-discuss mailing list > perf-discuss@opensolaris.org > Thanks Zhihui _______________________________________________ perf-discuss mailing list perf-discuss@opensolaris.org
