hands-on/system_information.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "\n",
    "# Information about the system & environment"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Install `sh` if it doesn't seem to be available."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "from datetime import datetime\n",
    "import os\n",
    "import platform\n",
    "import psutil\n",
    "try:\n",
    "    import sh\n",
    "except ModuleNotFoundError:\n",
    "    print('installing sh using pip')\n",
    "    !pip install sh\n",
    "    import sh\n",
    "import sys"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Note that `psutil` is not in Python's standard library."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Operating system"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Using the `platform` module, it is easy to obtain information on the platform the Python interpreter is running on."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Information about the machine name:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "platform.node()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The architecture and hardware:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "platform.processor()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "sys.byteorder"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "os.cpu_count()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "os.sched_getaffinity(0)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The operating system:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "platform.system()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "platform.release()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "platform.version()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "platform.platform()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Numerics"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The properties of floating point numbers can be obtained easily from the `sys.floatinfo` object."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The largest floating point value that can be represented, the smallest positive non-zero value:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(sys.float_info.max, sys.float_info.min)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The number of significant digits of a floating point value:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "sys.float_info.dig"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Processes"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Detailed information is available on the processes running on the system."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for process in psutil.process_iter():\n",
    "    if 'python' in process.name():\n",
    "        cpu_times = process.cpu_times()\n",
    "        thread_str = f'threads: {process.num_threads()}'\n",
    "        cpu_str = f'user: {cpu_times.user}, sys: {cpu_times.system}'\n",
    "        print(f'{process.pid}: {process.name()} ({thread_str}, {cpu_str})')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "CPU times are cumulative over the process' life time."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for process in psutil.process_iter():\n",
    "    if process.cpu_times().user > 0.1:\n",
    "        print(f'{process.name()}: {process.cpu_times().user}')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "It is easy to kill processes, so you might want to be careful."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "sleep = sh.sleep(120, _bg=True)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for process in psutil.process_iter():\n",
    "    if 'sleep' in process.name():\n",
    "        print(process)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "name = 'sleep'\n",
    "killed_pids = []\n",
    "for process in psutil.process_iter():\n",
    "    if name == process.name():\n",
    "        print(f'killing {name}...')\n",
    "        killed_pids.append(process.pid)\n",
    "        process.kill()\n",
    "print('killed: ', ', '.join(map(str, killed_pids)))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Users"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "You can retrieve information on the users on the system as well."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for user in psutil.users():\n",
    "    started = datetime.strftime(datetime.fromtimestamp(user.started),\n",
    "                                '%Y-%m-%d %H:%M:%S')\n",
    "    print(f'{user.name}: {started}')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Performance"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The `psutil` module makes quite some interesting statistics related to system performance available. This can be useful when writing monitoring tools."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The cumulative times for user, nice, system and so on are readily available."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "psutil.cpu_times()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Memory usage can be queried."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "psutil.virtual_memory()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Disk I/O measures such as the total IOP and read/write sizes in byte are easy to obain."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "psutil.disk_io_counters()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Network I/O can similarly be monitored."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "psutil.net_io_counters()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Disk usage for all partitions can be queried."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for partition in psutil.disk_partitions():\n",
    "    mountpoint = partition.mountpoint\n",
    "    if 'snap' not in mountpoint:\n",
    "        print(f'{mountpoint}: {psutil.disk_usage(mountpoint).percent:.1f}')"
   ]
  }
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