topic Jithin, in Software Tuning, Performance Optimization & Platform Monitoring

Using PEBS facility

Jithin_Parayil_T_ — Sun, 01 Mar 2015 04:26:22 GMT

Hi,

I've been going through the documentation for the PEBS facility as described in the Intel software-developer manual vol 3b section 18.7.1.1

It is mentioned that, in order to use PEBS, software needs to initialize the DS_BUFFER_MANAGEMENT_AREA data structure in memory (in non-paged pool) and then store the beginning linear address of this data structure in the IA32_DS_AREA register.

Is there a sample piece of code that illustrates how this data structure initialization and setting of IA32_DS_AREA register needs to be done?

I'm a bit confused about using PEBS and haven't been able to find any useful examples of how PEBS is utilized either.

It would be quite helpful if I could refer to a piece of sample code that configures and utilizes PEBS?

I'm working on an IvyBridge machine.

Thanks in advance,

Jithin

Jithin,

Thomas_W_Intel — Mon, 02 Mar 2015 09:16:03 GMT

Jithin,

did you have a look at the pmu-tools that Andi has put on github? It contains the code to access raw PEBS information.

Best regards

Thomas

Thanks a lot Thomas!

Jithin_Parayil_T_ — Thu, 05 Mar 2015 04:51:40 GMT

Thanks a lot Thomas!

I went through the pebs-grabber module in the pmu-tools repo and it cleared a lot of doubts.

However, I ran into an issue while trying to use the module.

Following are the commands I used to build the code and use it (I followed these commands from the comments mentioned in pebs-grabber.c):

1. make [KDIR=/lib/modules/3.13.0-46-generic/build]

2. insmod pebs-grabber.ko

3. perf record -e cycles:p,pebs_v1,pebs\_v2 ../../a.out

The third command hits an error:

invalid or unsupported event: 'cycles:p,pebs_v1,pebs_v2'

Run 'perf list' for a list of valid events

Have I missed something?

Thanks,

Jithin

Mike_U_ — Thu, 10 Dec 2015 23:10:35 GMT

I am also trying to use this toolset.

I can get the simple-pebs driver compiled and installed.

when I try to follow the above instructions to get the pebs-grabber module installed, it fails.

dmesg says:

pebs-grabber: PEBS version 2

pebs-grabber: Cannot register kprobe: -2

this is with kernel linux-4.2.0-19