Races and Barriers

Initialization

• An "auto-load safe-path" should be set in ~/.gdbinit, either / or a path to this directory:

echo "set auto-load safe-path /" >> ~/.gdbinit

• Install libraries required for Qemu and Buildroot:

# Fedora
sudo dnf install \
  ncurses-devel perl-ExtUtils-MakeMaker ninja-build \
  glib2-devel pixman-devel libslirp-devel \
  perl-IPC-Cmd perl-open lz4 gawk make gcc \
  libmpc-devel gmp-devel

# Ubuntu
sudo apt install \
  libncurses-dev libextutils-makemaker-cpanfile-perl ninja-build \
  libglib2.0-dev libpixman-1-dev libslirp-dev
  libipc-run-perl lz4 gawk make gcc \
  libmpc-dev libgmp-dev

• Build everything:

./init_build.sh

---

Running Optimization Demo

• Start Qemu

./8_run.sh

• Enter login root (without password)
• Run the compiler barriers demo

/opt/compiler_opts

• Run the CPU barriers demo

/opt/cpu_opts

• Read and edit the code

$EDITOR demo_races/compiler_opts.c
$EDITOR demo_races/cpu_opts.c

• Rebuild and re-run

./rebuild_rerun.sh

• Exit Qemu with key combination Ctrl + A, X or poweroff

• Run on a local machine:

% ./output/cpu_opts
without barriers: !A!B    942, !AB     24, A!B     33, AB      0
with barriers: !A!B      0, !AB      2, A!B      4, AB    993
%