1#!/usr/bin/env python32# ignore-tidy-file-linelength34# This is a small script that we use on CI to collect CPU usage statistics of5# our builders. By seeing graphs of CPU usage over time we hope to correlate6# that with possible improvements to Rust's own build system, ideally diagnosing7# that either builders are always fully using their CPU resources or they're8# idle for long stretches of time.9#10# This script is relatively simple, but it's platform specific. Each platform11# (OSX/Windows/Linux) has a different way of calculating the current state of12# CPU at a point in time. We then compare two captured states to determine the13# percentage of time spent in one state versus another. The state capturing is14# all platform-specific but the loop at the bottom is the cross platform part15# that executes everywhere.16#17# # Viewing statistics18#19# All builders will upload their CPU statistics as CSV files to our S3 buckets.20# These URLS look like:21#22#   https://$bucket.s3.amazonaws.com/rustc-builds/$commit/cpu-$builder.csv23#24# for example25#26#   https://rust-lang-ci2.s3.amazonaws.com/rustc-builds/68baada19cd5340f05f0db15a3e16d6671609bcc/cpu-x86_64-apple.csv27#28# Each CSV file has two columns. The first is the timestamp of the measurement29# and the second column is the % of idle cpu time in that time slice. Ideally30# the second column is always zero.31#32# Once you've downloaded a file there's various ways to plot it and visualize33# it. For command line usage you use the `src/etc/cpu-usage-over-time-plot.sh`34# script in this repository.3536import datetime37import sys38import time3940# Python 3.3 changed the value of `sys.platform` on Linux from "linux2" to just41# "linux". We check here with `.startswith` to keep compatibility with older42# Python versions (especially Python 2.7).43if sys.platform.startswith("linux"):4445    class State:46        def __init__(self):47            with open("/proc/stat", "r") as file:48                data = file.readline().split()49            if data[0] != "cpu":50                raise Exception('did not start with "cpu"')51            self.user = int(data[1])52            self.nice = int(data[2])53            self.system = int(data[3])54            self.idle = int(data[4])55            self.iowait = int(data[5])56            self.irq = int(data[6])57            self.softirq = int(data[7])58            self.steal = int(data[8])59            self.guest = int(data[9])60            self.guest_nice = int(data[10])6162        def idle_since(self, prev):63            user = self.user - prev.user64            nice = self.nice - prev.nice65            system = self.system - prev.system66            idle = self.idle - prev.idle67            iowait = self.iowait - prev.iowait68            irq = self.irq - prev.irq69            softirq = self.softirq - prev.softirq70            steal = self.steal - prev.steal71            guest = self.guest - prev.guest72            guest_nice = self.guest_nice - prev.guest_nice73            total = (74                user75                + nice76                + system77                + idle78                + iowait79                + irq80                + softirq81                + steal82                + guest83                + guest_nice84            )85            return float(idle) / float(total) * 1008687elif sys.platform == "win32":88    from ctypes.wintypes import DWORD89    from ctypes import Structure, windll, WinError, GetLastError, byref9091    class FILETIME(Structure):92        _fields_ = [93            ("dwLowDateTime", DWORD),94            ("dwHighDateTime", DWORD),95        ]9697    class State:98        def __init__(self):99            idle, kernel, user = FILETIME(), FILETIME(), FILETIME()100101            success = windll.kernel32.GetSystemTimes(102                byref(idle),103                byref(kernel),104                byref(user),105            )106107            assert success, WinError(GetLastError())[1]108109            self.idle = (idle.dwHighDateTime << 32) | idle.dwLowDateTime110            self.kernel = (kernel.dwHighDateTime << 32) | kernel.dwLowDateTime111            self.user = (user.dwHighDateTime << 32) | user.dwLowDateTime112113        def idle_since(self, prev):114            idle = self.idle - prev.idle115            user = self.user - prev.user116            kernel = self.kernel - prev.kernel117            return float(idle) / float(user + kernel) * 100118119elif sys.platform == "darwin":120    from ctypes import *121122    libc = cdll.LoadLibrary("/usr/lib/libc.dylib")123124    class host_cpu_load_info_data_t(Structure):125        _fields_ = [("cpu_ticks", c_uint * 4)]126127    host_statistics = libc.host_statistics128    host_statistics.argtypes = [129        c_uint,130        c_int,131        POINTER(host_cpu_load_info_data_t),132        POINTER(c_int),133    ]134    host_statistics.restype = c_int135136    CPU_STATE_USER = 0137    CPU_STATE_SYSTEM = 1138    CPU_STATE_IDLE = 2139    CPU_STATE_NICE = 3140141    class State:142        def __init__(self):143            stats = host_cpu_load_info_data_t()144            count = c_int(4)  # HOST_CPU_LOAD_INFO_COUNT145            err = libc.host_statistics(146                libc.mach_host_self(),147                c_int(3),  # HOST_CPU_LOAD_INFO148                byref(stats),149                byref(count),150            )151            assert err == 0152            self.system = stats.cpu_ticks[CPU_STATE_SYSTEM]153            self.user = stats.cpu_ticks[CPU_STATE_USER]154            self.idle = stats.cpu_ticks[CPU_STATE_IDLE]155            self.nice = stats.cpu_ticks[CPU_STATE_NICE]156157        def idle_since(self, prev):158            user = self.user - prev.user159            system = self.system - prev.system160            idle = self.idle - prev.idle161            nice = self.nice - prev.nice162            return float(idle) / float(user + system + idle + nice) * 100.0163164else:165    print("unknown platform", sys.platform)166    sys.exit(1)167168cur_state = State()169print("Time,Idle")170while True:171    time.sleep(1)172    next_state = State()173    now = datetime.datetime.now(datetime.timezone.utc).replace(tzinfo=None).isoformat()174    idle = next_state.idle_since(cur_state)175    print("%s,%s" % (now, idle))176    sys.stdout.flush()177    cur_state = next_state