EasySHM

High-Performance Shared Memory IPC for Python.

EasySHM is a low-latency communication library that allows Python processes to share data directly through RAM.

Features

• Zero-Socket IPC: No open ports, no network overhead.
• Kernel-Level Signaling: Uses a futex (Linux), POSIX semaphores (macOS) or Win32 Events (Windows) to wake every waiting process at once.
• Auto-Grow: Dynamic memory segment resizing without stopping the system.
• NumPy Zero-Copy: Share large arrays at RAM speeds (Giga-octets per second).
• Thread-Safe & Process-Safe: Built-in locking mechanism.

Installation

pip install py-easyshm

Quick Start

from easyshm import EasySHM
import ctypes

# Create or join a shared segment
shm = EasySHM("my_data", size=1024)

# 1. Use it as a NumPy array (Zero-Copy)
arr = shm.as_view("numpy", shape=(10,), dtype='float32')
arr[0] = 42.0

# 2. Use it as a C-Structure (Zero-Copy)
class Point(ctypes.Structure):
    _fields_ = [("x", ctypes.c_int), ("y", ctypes.c_int)]

p = shm.as_view("struct", type=Point)
p.x = 100

# 3. Use it as a PyTorch Tensor
import torch
t = shm.as_view("torch", shape=(10,))

Architecture

EasySHM is platform-agnostic:

• Windows: Uses CreateFileMapping and session-scoped Named Events (Local\).
• Linux/Unix: Uses POSIX mmap and Semaphores in /dev/shm.

Advanced Views

EasySHM now supports an extensible View Registry. You can map any typed structure directly over shared bytes without copies.

• as_view("numpy", shape, dtype)
• as_view("struct", type=MyCtypesStruct)
• as_view("torch", shape, dtype)

Performance

Measured with python benchmarks/latency.py (two processes, thousands of round trips; Linux/WSL2, Python 3.12):

Latency is dominated by Python itself, so a localhost socket is still faster for tiny messages. EasySHM is useful when several processes share the same (large) state without resending it, with no port to open. Run the benchmark on your own machine for real numbers.

Part of the EasySync ecosystem. Created by GalTechDev.