PiMsimulation

PiM simulation with Gem5 & Ramulator

Introduction

This repository is for simulating PiM using Gem5 -the process simulator- and Ramulator -the memory simulator. PiM model simulated in this repository is quite simple. It receives the address, and increases the value stored in the given address by 1.

Environment

• Server environment: Ubuntu 20.04
• Simulated CPU architecture: RISCV
• Simulated Memory: DDR4

Directory / File info

Figure: Control & Data flow while simlating PiM using Gem5 & Ramulator

Ramulator

• Main.cpp: Receive parameter in ramulator runtime & execute get_dramtrace_request (Processor.cpp)
• Processor.cpp: determine the type of request (read / write / pim)
• Memory.h / Controller.h: execute memory.tick()
• DDR4.h: you can adjust the variable nPim here
  • nPim: Clocks taken for executing pim calculation.

Gem5

• src/arch/riscv/isa/
  • decoder.isa: decode instruction and generate request
  • mem.isa: definition for generating and operating request
• src/cpu/
  • simple/atomic.hh: definition for function of simple atomic CPU
  • simple/timing.cc: definition for function of simple timing CPU (definition for pimMem)
• src/mem/
  • abstract_memory.cc: abstraction layer for memory models
  • ramulator.cc: modified lines in recvTimingReq in order to send PIM type request
• progs/
  • mem_test.c, pim_test.c, nop_test.c: test files

Cross compiler

• xcompiler/riscv-opcodes/: allocating match and mask bits for custom instruction
• xcompiler/riscv-gnu-toolchain/: modify compiler and build it

Build

# Solve gem5 & ramulator Dependency
sudo apt install build-essential git m4 scons zlib1g zlib1g-dev \
libprotobuf-dev protobuf-compiler libprotoc-dev libgoogle-perftools-dev \ 
python3-dev python-is-python3 libboost-all-dev pkg-config


# Solve cross compiler Dependency
sudo apt-get install autoconf automake autotools-dev curl python3 libmpc-dev \
libmpfr-dev libgmp-dev gawk build-essential bison flex texinfo gperf libtool patchutils bc \
zlib1g-dev libexpat-dev device-tree-compiler


# Build PiM Simulator
git clone https://github.com/RohSiHyun/PiMsimulation.git
cd PiMsimulation/gem5
scons build/RISCV/gem5.opt -j 32


# Build Cross compiler
cd ../xcompiler
cd riscv-gnu-toolchain
./configure --prefix={absolute path for installing cross compiler}
make -j 32


# Execute simulation
./run.sh


# You can see more details by looking into run.sh
# run.sh builds debug_pim and debug_mem files and you can see the simulation results

Error Handling

If build fails with message "config/have_deprecated_namespace.hh: No such file or directory", please modify gem5/src/base/compiler.hh

1. delete line 46 (#include "config/have_deprecated_namespace.hh")
2. add new line (#define HAVE_DEPRECATED_NAMESPACE 1)

This version is uploaded on NSsolution branch