TheRock/rocm-systems/projects/rocprofiler-systems/examples/shmem

SHMEM

Overview

This directory contains two OpenSHMEM examples. shmem-hello demonstrates basic SHMEM initialization, symmetric memory allocation, and remote read operations between processing elements (PEs). shmem-pingpong implements a latency microbenchmark that measures round-trip message passing time between two PEs using various SHMEM communication strategies (polling, shmem_wait_until, shmem_fence, shmem_quiet). These examples are useful for profiling one-sided communication patterns in PGAS (Partitioned Global Address Space) programming models.

Source Files

• shmem-hello.c - Initializes SHMEM, allocates symmetric memory with shmem_malloc(), performs shmem_int_get() from the next PE (circular), and prints the result.
• shmem-pingpong.c - Ping-pong latency benchmark with configurable message size, iteration count, and communication mode. Supports polling, shmem_wait_until(), shmem_fence(), shmem_quiet(), and global vs. heap data placement.

Prerequisites

• CMake 3.25+
• OpenSHMEM implementation with oshcc compiler wrapper

Building

Standalone build:

cmake -B <build_dir> -S <project_root>/examples/shmem
cmake --build <build_dir>

As part of the examples suite:

cmake -B <build_dir> -S <project_root>/examples/
cmake --build <build_dir> --target shmem-hello shmem-pingpong

Targets:

Target	Description
shmem-hello	Basic SHMEM hello world
shmem-pingpong	Ping-pong latency benchmark

Running

# Hello world (any number of PEs)
oshrun -np 4 ./shmem-hello

# Ping-pong (requires exactly 2 PEs)
oshrun -np 2 ./shmem-pingpong

shmem-pingpong flags:

Flag	Description	Default
-n	Number of iterations	10000
-s	Message size in bytes	4
-w	Use shmem_wait_until() instead of polling	off
-f	Send data and flag separately with shmem_fence()	off
-g	Use global data instead of heap	off
-q	Call shmem_quiet() after each put	off

Profiling with rocprofiler-systems

oshrun -np 2 rocprof-sys-run -- ./shmem-pingpong -n 1000

Recommended Configuration

Variable	Value	Purpose
ROCPROFSYS_TRACE	true	Generate Perfetto trace
ROCPROFSYS_PROFILE	true	Generate call-stack profile
ROCPROFSYS_USE_SAMPLING	ON	Enable statistical sampling
ROCPROFSYS_SAMPLING_FREQ	50	Sampling frequency (interrupts/sec)