Getting no. of PCIe reads to LLC (PCIeRdCur) inside my c++ program

[Berry_sh]

I want to get PCIRdCur (no. of reads to LLC) in my .cpp file, so what I did was using programPCIeEventGroup() and passed to it a vector of events that I want to monitor, more specifically PCIRdCur_miss (uint_64 of {0x00043c33}) and PCIRdCur_hit (uint_64 of {0x00043c37}).

1- First of all, is that the correct way to determine which events to monitor? And given that my CPU's microarchitecture is cascaded lake (CLX), can I program more than 1 event to monitor? The reason I am asking is that I found inside CPUCounters.cpp the following sentence: "//JKT through СLX generations allow programming only one required event at a time"

Then, I called getPCIeCounterData(socket_no, ctr). The thing is that I am not sure what to specify as ctr. My understanding is that ctr ranges from 0 to 3 (otherwise, it gives segmentation fault).

2- The question is if the 0-3 range of the ctr variable corresponds to (0)PCIRdCur(RFO/CRd/DRd), and (1)ItoM, and (2)PRd, and (3)WiL, respectively. The reason I guessed so is because in pcm-pcie.h, it loops from ctr = 0 to ctr = eventGroup.size(), so I assumed ctr is used to represent these events. Is this right?

3- If that is the case, why does getPCIeCounterData function still displays values when ctr = 1 (monitoring ItoM) while I have already programmed the event group to only monitor PCIRdCur?

4- Finally, why does the output given by getPCIeCounterData never match the PCIRdCur column when I run pcm-pcie command from that terminal? I understand that they are not printed exactly at the same exact time (I ran my c++ that keeps printing  getPCIeCounterData (0, 0) while(true) and then I ran pcm-pcie) but I assume they should display similar order of magnitude.

Thanks for your help in advance.

[IsaacQ_Intel]

Dear Berry_sh,

Thank you for your post on the Intel® communities. We appreciate your engagement, and we are here to provide assistance with your concern.

Based on the nature of your issue, it appears you are involved in software development. Our dedicated team will promptly review your inquiry and respond accordingly.

Kind regards,

Isaac Q.

Intel Customer Support Technician

[Berry_sh]

Thanks for your reply.

Is someone still looking into the issue?

[shivani19]

Hi! Thank you for posting your query. Could you let us know if you are using any Intel Compiler/Intel Software to run the program? We will be happy to investigate your queries. 

Have a nice day!

[shivani19]

Beatrice, unfortunately we were unable to hear back from you. If you have any further query, please post a new question as this thread will no longer be monitored by Intel®.