Adding performance counter via EventSel and UMask

[Joshua Kalyanapu]

I want to collect raw performance counters, no derived ones. I am using Intel's list of performance counters for my architecture, documented here: 

https://perfmon-events.intel.com/platforms/sapphirerapids/core-events/core/#core-events. 

I have found most of these performance counters work just fine using 

PAPI_event_name_to_code(name, &code); 
PAPI_add_event(eventset, code). 

However, there are some (around 40 of them) that do not have PAPI_event_name_to_code return PAPI_OK so I can't use them in this manner. 

One such example is L1D.HWPF_MISS. The perfmon-events page specifies that this counter's EventSel is 51H and UMask is 20H. I have confirmed with perf that this counter returns nonzero values without error, so I know it's possible to program this counter. Is there a way to program an event in PAPI using only EventSel and UMask? I am using PAPI 7.1.0.0. 

[Daniel Barry]

Hi Joshua,

I indeed see the event L1D.HWPF_MISS listed in the published events list: https://github.com/intel/perfmon/blob/main/SPR/events/sapphirerapids_core.json

It appears that this event is missing from the latest libpfm4 (lib/events/intel_spr_events.h).

I have CCed Stephane, who maintains libpfm4.

@Stephane Is there a reason that this event is not in libpfm4? If there are no technical limitations to this event being added, then I can provide a patch that adds this (and other) events to libpfm4.

Thank you,
Daniel Barry

[Joshua Kalyanapu]

Great! If it helps, I've included a full list from that page of the core events I am unable to program with PAPI at the bottom of this message. I am in a bit of a rush though, so in the meantime is there a way to add an event using just EventSel and UMask?

    'BACLEARS.ANY',
    'CORE_SNOOP_RESPONSE.I_FWD_FE',
    'CORE_SNOOP_RESPONSE.I_FWD_M',
    'CORE_SNOOP_RESPONSE.I_HIT_FSE',
    'CORE_SNOOP_RESPONSE.MISS',
    'CORE_SNOOP_RESPONSE.S_FWD_FE',
    'CORE_SNOOP_RESPONSE.S_FWD_M',
    'CORE_SNOOP_RESPONSE.S_HIT_FSE',
    'CYCLE_ACTIVITY.STALLS_L3_MISS',
    'EXE_ACTIVITY.2_3_PORTS_UTIL',
    'EXE_ACTIVITY.EXE_BOUND_0_PORTS',
    'HW_INTERRUPTS.MASKED',
    'HW_INTERRUPTS.PENDING_AND_MASKED',
    'HW_INTERRUPTS.RECEIVED',
    'ICACHE_DATA.STALL_PERIODS',
    'IDQ_UOPS_NOT_DELIVERED.CYCLES_0_UOPS_DELIV.CORE',
    'L1D.HWPF_MISS',
    'L2_RQSTS.ALL_HWPF',
    'L2_RQSTS.HWPF_MISS',
    'L2_RQSTS.MISS',
    'L2_RQSTS.REFERENCES',
    'L2_TRANS.L2_WB',
    'MEM_LOAD_L3_HIT_RETIRED.XSNP_FWD',
    'MEM_LOAD_L3_HIT_RETIRED.XSNP_MISS',
    'MEM_LOAD_L3_HIT_RETIRED.XSNP_NO_FWD',
    'MEM_LOAD_L3_HIT_RETIRED.XSNP_NONE',
    'MEM_LOAD_L3_MISS_RETIRED.LOCAL_DRAM',
    'MEM_LOAD_L3_MISS_RETIRED.REMOTE_DRAM',
    'MEM_LOAD_L3_MISS_RETIRED.REMOTE_FWD',
    'MEM_LOAD_L3_MISS_RETIRED.REMOTE_HITM',
    'MEM_LOAD_L3_MISS_RETIRED.REMOTE_PMM',
    'MEM_TRANS_RETIRED.LOAD_LATENCY_GT_1024',
    'MEM_TRANS_RETIRED.LOAD_LATENCY_GT_128',
    'MEM_TRANS_RETIRED.LOAD_LATENCY_GT_16',
    'MEM_TRANS_RETIRED.LOAD_LATENCY_GT_256',
    'MEM_TRANS_RETIRED.LOAD_LATENCY_GT_32',
    'MEM_TRANS_RETIRED.LOAD_LATENCY_GT_4',
    'MEM_TRANS_RETIRED.LOAD_LATENCY_GT_512',
    'MEM_TRANS_RETIRED.LOAD_LATENCY_GT_64',
    'MEM_TRANS_RETIRED.LOAD_LATENCY_GT_8',
    'OFFCORE_REQUESTS.DEMAND_CODE_RD',
    'OFFCORE_REQUESTS.DEMAND_RFO',
    'OFFCORE_REQUESTS.L3_MISS_DEMAND_DATA_RD',
    'OFFCORE_REQUESTS_OUTSTANDING.CYCLES_WITH_DEMAND_CODE_RD',
    'OFFCORE_REQUESTS_OUTSTANDING.CYCLES_WITH_DEMAND_DATA_RD',
    'OFFCORE_REQUESTS_OUTSTANDING.DEMAND_CODE_RD',
    'OFFCORE_REQUESTS_OUTSTANDING.DEMAND_DATA_RD',
    'OFFCORE_REQUESTS_OUTSTANDING.L3_MISS_DEMAND_DATA_RD',
    'RS.EMPTY_RESOURCE',
    'SW_PREFETCH_ACCESS.ANY',
    'UOPS_ISSUED.CYCLES',

[Daniel Barry]

Hi Joshua,

There is indeed a way to do this using the "perf_raw" event in PAPI. I will walk through how to use this, using the event "FP_ARITH_INST_RETIRED.SCALAR_DOUBLE" from the link you provided.

This event has the following:

EventSel=C7H

UMask=01H

We add this to an event set using the event name "perf_raw::r01C7", so when using the utility papi_command_line:
> $> papi_command_line perf_raw::r01C7

>
>This utility lets you add events from the command line interface to see if they work.
>
>Successfully added: perf_raw::r01C7
>
>perf_raw::r01C7 :       40000000
>
>----------------------------------

This event count is correct because the utility performs precisely 40000000 double-precision FLOPs.

> The perfmon-events page specifies that this counter's EventSel is 51H and UMask is 20H.

In your case, the event "L1D.HWPF_MISS" corresponds to "perf_raw::r2051", which can be used in PAPI.

Thank you,
Daniel Barry