def perfstat()

in perfrunbook/utilities/measure_and_plot_basic_pmu_counters.py [0:0]

• 17 lines of code
• 5 McCabe index (conditional complexity)

def perfstat(time, period, cpus, counter_numerator, counter_denominator, __unused__):
    """
    Measure performance counters using perf-stat in a subprocess.  Return a CSV buffer of the values measured.
    """
    try:
        if not cpus:
            res = subprocess.run(["lscpu", "-p=CPU"], check=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
            output = io.StringIO(res.stdout.decode('utf-8'))
            cpus = []
            for line in output.readlines():
                match = re.search(r'''^(\d+)$''', line)
                if match is not None:
                    cpus.append(match.group(1))

        res = subprocess.run(["perf", "stat", f"-C{','.join(cpus)}", f"-I{period}", "-x|", "-a", "-e", f"{counter_numerator}", "-e", f"{counter_denominator}", "--", "sleep", f"{time}"],
                             check=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
        return io.StringIO(res.stdout.decode('utf-8'))
    except subprocess.CalledProcessError:
        print("Failed to measure performance counters.")
        print("Please check that perf is installed using install_perfrunbook_dependencies.sh and in your PATH")
        return None