add-counter

name	add-counter
description	Add a new statistics counter to GPGPU-Sim. Guides through declaring, initializing, incrementing, and registering metric counters.

When the user invokes this skill, help them add a new statistics counter to GPGPU-Sim.

Arguments: $ARGUMENTS

Overview

GPGPU-Sim uses a statistics framework in gpu-simulator/gpgpu-sim/src/statistics.h. Reference implementation: chiplet_queue_full.

Counter Types

Available in Statistics:: namespace:

• UInt64SingleStatsCounter - Single global counter
• UInt64MultiUnitStatsCounter - Per-unit counters (e.g., per sub-partition, per SM)
• Float32SingleStatsCounter / Float32MultiUnitStatsCounter - Float versions

Implementation Steps

Step 1: Declare the counter

Add to an appropriate stats header. Common locations:

• src/gpgpu-sim/mem_latency_stat.h - Memory system stats
• src/gpgpu-sim/shader.h (shader_core_stats class) - Shader/core stats

// Single global counter
Statistics::UInt64SingleStatsCounter my_global_counter;

// Per-unit counter (e.g., per sub-partition)
Statistics::UInt64MultiUnitStatsCounter my_per_unit_counter;

Step 2: Initialize in constructor

Add to the member initializer list in the corresponding .cc file:

// Single counter: (name, description, initial_value)
my_global_counter("my_global_counter", "Description of the metric", 0),

// Multi-unit counter: (name, description, num_units, initial_value)
my_per_unit_counter("my_per_unit_counter", "Per-unit description",
                    mem_config->m_n_mem_sub_partition, 0),

Step 3: Increment counter in code

Place increment at the appropriate location:

// Single counter
++m_mem_stats->my_global_counter;

// Per-unit counter (by index)
++m_mem_stats->my_per_unit_counter[m_sub_partition_id];

Step 4: Register for performance counters (optional)

To make the counter visible in perf sampling output (for hardware validation), add in gpu-sim.cc around line 1248:

perf_counters.add_statistics_counter(m_memory_stats->my_per_unit_counter);

Reference Files

File	Purpose
mem_latency_stat.h:165	Declaration example (chiplet_queue_full)
mem_latency_stat.cc:88-91	Initialization example
l2cache.cc:1123	Increment example
gpu-sim.cc:1248-1252	Perf counter registration

Workflow

When adding a counter:

1. Ask user: counter name, type (single/multi-unit), which stats class, where to increment
2. Make the edits in order: header declaration, constructor init, increment location
3. Optionally add perf counter registration if needed for HW validation