Error in event mask for reading memory load latency information using PEBS on Haswell

sbhal1 — Fri, 08 Jul 2016 21:51:39 GMT

Hi,

I was trying to read the memory latency information for a program using the information in Intel Software Developer Manual Vol 3B Page 18-39 under "18.8.1.2 Load Latency Performance Monitoring Facility" published in April 2016 for Haswell.

It says that LATENCY_ABOVE_THRESHOLD event mask must be specified (IA32_PerfEvtSelX[15:0] = 100H), which is wrong and does not give you any output except 0.

You need to specify IA32_PerfEvtSelX[15:0] = 1CDH to get correct values out of the cores.

I am posting this here because I have already spent countless hours to figure this out and do not want anyone else to waste his/her time.

Hope this helps.

PS: It would be great if Intel could correct this in the future versions of the software manual.

Best,

Sridutt

topic Error in event mask for reading memory load latency information using PEBS on Haswell in Software Tuning, Performance Optimization & Platform Monitoring

Error in event mask for reading memory load latency information using PEBS on Haswell