topic yes in Software Tuning, Performance Optimization & Platform Monitoring

Offcore\Uncore events in Intel PCM

Max_R_ — Thu, 07 Feb 2013 13:53:32 GMT

Hello everybody.

Recently I have started using Intel Performance Counters Monitor tool, version 2.3. As far as i understood, I may cutomize it a bit in order to measure the desired metrics. However, one question appeared:

Does PCM support uncore\offcore events of SandyBridge\IvyBridge processors? (usual ones, not EP) The ones I need are:

OFFCORE_RESPONSE_0:ANY_DATA:LLC_MISS_LOCAL
OFFCORE_RESPONSE_0:ANY_RFO:LLC_MISS_LOCAL
UNC_CBO_CACHE_LOOKUP:STATE_I:ANY
UNC_ARB_TRK_REQUEST:WRITES
UNC_ARB_TRK_REQUEST:EVICTIONS

Also, when I launch ./pcm-x it shows "N/A" in the Read / Write columns.

Thanks in advance.

I've been told that this

David_Cherkus — Thu, 07 Feb 2013 16:27:50 GMT

I've been told that this support requires support from the BIOS, so it may or may not work on a given platform.

This is true for the PCM tool as well as many other tools/libraries that want to get this information.

I've been told the "Romley" Sandy Bridge reference platform does not have such support, and have not been told of plans to add such support.

I can't find the threads that say this, but they are on software.intel.com.

HTH,

Dave

Some of the threads I was

David_Cherkus — Thu, 07 Feb 2013 16:37:00 GMT

Some of the threads I was thinking of are:

Not sure if these map 100% to what you are trying to accomplish...

Dave

>>>I've been told that this

Bernard — Fri, 08 Feb 2013 06:29:17 GMT

>>>I've been told that this support requires support from the BIOS, so it may or may not work on a given platform>>>

Uncore PMU registers both control and counters can be accessed by kernel mode driver (Windows platform).

You get N/A for READ/WRITE

Shailen_Sobhee — Thu, 31 Jul 2014 11:52:29 GMT

You get N/A for READ/WRITE for the cores because this measurement is not available at the core level, but at the socket level.

David was referring to the

Thomas_W_Intel — Thu, 31 Jul 2014 13:12:19 GMT

David was referring to the counters for the QPI traffic. Especially on Intel Xeon E5-2600 processors, these counters are often hidden by the BIOS. Please see this article for details.

I am reviewing performance

Jack_C_ — Wed, 10 Sep 2014 07:19:51 GMT

I am reviewing performance counter these days. I found that the number of counter is less than total events.

I want to know if there is any solution to monitor most of the events.

Or I only can select 4 or 8 events to monitor.

Thanks

Jack

Jack,

Roman_D_Intel — Wed, 10 Sep 2014 08:36:58 GMT

Jack,

the technique to monitor more events than the number of hardware counters is called "event multiplexing". The performance tool monitors different subsets of events for short periods of time and then extrapolates the event counts to the whole measurement period. This works well for steady state workloads but not for workloads with rapidly changing characteristics. Intel PCM does not support multiplexing but there are other PMU tools that do: for example Intel VTune Amplifier XE.

Roman

Hi Roman,

Jack_C_ — Wed, 10 Sep 2014 09:04:04 GMT

Hi Roman,

It's very appreciate. So you mean if I want to monitor more events. I need to re-program counter and event select to monitor another group of events. Right ?

Jack

yes

Roman_D_Intel — Wed, 10 Sep 2014 09:05:15 GMT

yes