Allow choosing specific regions to measure via instrumentation API

pramodk commented 1 month ago

We have Caliper based instrumentation which allows to measure different phases like state updates, solver, current update, spike exchange etc. We also record the calls to each MOD file, e.g. state-hh, cur-hh.
If we have large number of MOD files and very few channel instances then such measurement could add significant measurement overhead.
E.g. In case of LIKWID, we see:

# without profiling
./x86_64/special -python test.py
NEURON RUN with 1 threads took 0.649262

# with likwid profiling
likwid-perfctr -C 0 -m -g FLOPS_DP x86_64/special -python test.py
NEURON RUN with 1 threads took 10.734261

i.e. 0.6 sec vs 10.73 sec

In such case, we want to selectively instrument a specific region. For example, the main psolve region or a specific mod file block like state-hh. This is now possible with a environmental variable NRN_PROFILE_REGIONS:

export NRN_PROFILE_REGIONS=psolve,state-hh
likwid-perfctr -C 0 -m -g FLOPS_DP x86_64/special -python test.py

....
NEURON RUN with 1 threads took 0.836292
...

Region psolve, Group 1: FLOPS_DP
+-------------------+------------+
|    Region Info    | HWThread 0 |
+-------------------+------------+
| RDTSC Runtime [s] |   0.835792 |
|     call count    |          1 |
+-------------------+------------+

+------------------------------------------+---------+------------+
|                   Event                  | Counter | HWThread 0 |
+------------------------------------------+---------+------------+
|             INSTR_RETIRED_ANY            |  FIXC0  | 5336280000 |
|           CPU_CLK_UNHALTED_CORE          |  FIXC1  | 1987773000 |
|           CPU_CLK_UNHALTED_REF           |  FIXC2  | 1523973000 |
| FP_ARITH_INST_RETIRED_128B_PACKED_DOUBLE |   PMC0  |     489202 |
|    FP_ARITH_INST_RETIRED_SCALAR_DOUBLE   |   PMC1  |  729407200 |
| FP_ARITH_INST_RETIRED_256B_PACKED_DOUBLE |   PMC2  |          0 |
| FP_ARITH_INST_RETIRED_512B_PACKED_DOUBLE |   PMC3  |      -     |
+------------------------------------------+---------+------------+
...
Region state-Nav1_6, Group 1: FLOPS_DP
+-------------------+------------+
|    Region Info    | HWThread 0 |
+-------------------+------------+
| RDTSC Runtime [s] |   0.167490 |
|     call count    |        400 |
+-------------------+------------+

+------------------------------------------+---------+------------+
|                   Event                  | Counter | HWThread 0 |
+------------------------------------------+---------+------------+
|             INSTR_RETIRED_ANY            |  FIXC0  | 1341566000 |
|           CPU_CLK_UNHALTED_CORE          |  FIXC1  |  505899600 |
|           CPU_CLK_UNHALTED_REF           |  FIXC2  |  387861900 |
| FP_ARITH_INST_RETIRED_128B_PACKED_DOUBLE |   PMC0  |          0 |
|    FP_ARITH_INST_RETIRED_SCALAR_DOUBLE   |   PMC1  |  224568600 |
| FP_ARITH_INST_RETIRED_256B_PACKED_DOUBLE |   PMC2  |          0 |
| FP_ARITH_INST_RETIRED_512B_PACKED_DOUBLE |   PMC3  |      -     |
+------------------------------------------+---------+------------+

i.e. only specified regions are enabled and with less overhead.

NOTE: I will document this in the developer docs in a separate PR including LIKWID

azure-pipelines[bot] commented 1 month ago

✔️ 2478ba880d67ecc22f3d638843f1dc4ae0f60249 -> Azure artifacts URL

codecov[bot] commented 1 month ago

Codecov Report

Attention: Patch coverage is 61.11111% with 7 lines in your changes missing coverage. Please review.

Project coverage is 67.28%. Comparing base (2ace814) to head (6578ba1).

Files	Patch %	Lines
src/coreneuron/utils/profile/profiler_interface.h	61.11%	7 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2983 +/- ## ========================================== - Coverage 67.29% 67.28% -0.01% ========================================== Files 572 572 Lines 104951 104967 +16 ========================================== + Hits 70626 70631 +5 - Misses 34325 34336 +11 ```

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