Add a benchmark configuration script

setup/bench_conf.py

@@ -0,0 +1,131 @@
+import subprocess
+from pprint import pprint
+from collections import namedtuple
+
+run = subprocess.check_output
+srun = run
+
+CPUInfo = namedtuple('CPUInfo', ['processor', 'physical_id', 'core_id'])
+
+def get_cpus():
+    with open('/proc/cpuinfo', 'r') as f:
+        raw_out = f.read()
+    relevant_lines = [l for l in raw_out.split('\n')
+                    if 'processor' in l or 'physical id' in l or 'core id' in l]
+    assert len(relevant_lines) % 3 == 0
+    line_data = [int(l[l.index(':') + 1:].strip()) for l in relevant_lines]
+
+    cpus = [CPUInfo(*line_data[i:i + 3]) for i in range(0, len(line_data), 3)]
+    assert len(cpus) % 2 == 0
+    return cpus
+
+
+def set_cpu_state(cpu, enabled):
+    with open('/sys/devices/system/cpu/cpu{}/online'.format(cpu.processor), 'w') as f:
+        f.write('1' if enabled else '0')
+
+
+################################################################################
+# HyperThreading
+################################################################################
+
+def disable_ht():
+    print('> Disabling HyperThreading...')
+
+    cpus = get_cpus()
+
+    seen_phys_cores = set()
+    cpus_to_disable = set()
+    for cpu in cpus:
+        key = (cpu.physical_id, cpu.core_id)
+        if key in seen_phys_cores:
+            cpus_to_disable.append(cpu)
+        else:
+            seen_phys_cores.add(key)
+
+    if len(cpus_to_disable) == 0:
+        print('    No cores with HyperThreading enabled found.')
+    elif len(cpus_to_disable) == (len(cpus) // 2):
+        print('    Disabling {} CPUs.'.format(len(cpus_to_disable)))
+    else:
+        raise RuntimeError('Expected to disable either exactly half or no CPUs. This might be a bug.')
+
+    return
+
+    for cpu in cpus_to_disable:
+        set_cpu_state(cpu, False)
+
+    return [cpu for cpu in cpus if cpu not in cpus_to_disable]
+
+
+def enable_ht():
+    for cpu in get_cpus():
+        set_cpu_state(cpu, True)
+
+
+################################################################################
+# cpusets
+################################################################################
+
+def shield_cpus(bench_cpus, bg_cpus):
+    return
+    bench_cpuspec = ','.join(str(cpu.processor) for cpu in bench_cpus)
+    bg_cpuspec = ','.join(str(cpu.processor) for cpu in bg_cpus)
+    # Set up our cpusets
+    srun(['cset', 'set', '--set=bg', '--cpu=' + bg_cpuspec, '--mem=1'])
+    srun(['cset', 'set', '--set=bench', '--cpu=' + bench_cpuspec, '--mem=0'])
+    # Move as many tasks (both userspace and kernel) as we can to the bg cpuset
+    srun(['cset', 'proc', '--move', '--fromset=root', '--toset=bg', '--kthread'])
+
+
+def remove_shield():
+    srun(['cset', 'set', '--destroy', '--set=bg'])
+    srun(['cset', 'set', '--destroy', '--set=bench'])
+
+################################################################################
+# CPU Turbo Mode
+################################################################################
+
+def set_turbo(value):
+    with open('/sys/devices/system/cpu/intel_pstate/no_turbo', 'w') as f:
+        f.write('0' if value else '1')
+
+################################################################################
+# Helpers
+################################################################################
+
+def isolate_bench_subset(cpus):
+    bench_cpus = [cpu for cpu in cpus if cpu.physical_id == 0]
+    bg_cpus = [cpu for cpu in cpus if cpu.physical_id != 0]
+    assert len(bench_cpus) > 0, "No CPUs on NUMA node 0!"
+    assert len(remaining_cpus) > 0, "Expected at least two NUMA nodes!"
+    return bench_cpus, bg_cpus
+
+################################################################################
+# Setup/Teardown
+################################################################################
+
+def setup_benchmark_env():
+    set_turbo(False)
+    all_active_cpus = disable_ht()
+    bench_cpus, bg_cpus = isolate_bench_subset(all_active_cpus)
+    shield_cpus(bench_cpus, bg_cpus)
+
+def teardown_benchmark_env():
+    remove_shield()
+    enable_ht()
+    set_turbo(True)
+
+def main():
+    parser = argparse.ArgumentParser(description='Configure benchmarking environment')
+    parser.add_argument('--setup', action='store_true')
+    parser.add_argument('--teardown', action='store_true')
+    args = parser.parse_args()
+
+    assert not args.setup and args.teardown
+    assert args.setup or args.teardown
+
+    if args.setup:
+        setup_benchmark_env()
+    else:
+        teardown_benchmark_env()