谁在使用GPU？

nvidia-smi命令可以查看GPU使用情况，但是只能看到占用每个GPU的进程ID。根据进程ID可以得到进程详情，进程详情中包括用户ID，根据用户ID可以获取用户名称，从而知道哪个用户在使用GPU。

import json
import os
import re
import sys
import time
import typing

import bidict

"""
查看谁在使用GPU
"""

def get_user_id_map() -> typing.Dict[str:str]:
    """获取用户名和用户ID的对应关系"""
    home = os.path.expanduser('~')
    users = bidict.bidict()
    for user_name in os.listdir(os.path.join(home, '..')):
        info = os.popen('id ' + user_name + ' 2>&1').read().strip()
        if 'no such user' in info: continue
        try:
            a = re.search("uid=(\\d+)\((\\w+)\)", info)
            users[a.group(1)] = a.group(2)  # userid==>username
        except Exception as e:
            print(e)
    return users

def nvidia_smi() -> (int, typing.Dict[str:str]):
    """使用nvidia-smi命令查看GPU使用情况，返回GPU个数和各个GPU的进程的描述line"""
    info = os.popen('nvidia-smi').read()
    info = info.split('\n')
    """
    smi信息分成上下两部分
    上面部分：以表格形式展示各个GPU的使用率
    下面部分：展示各个GPU上运行的进程ID
    """
    space_ind = 0
    for ind, line in enumerate(info):
        if not line.strip():
            space_ind = ind
            break

    first_line = 0
    for ind, line in enumerate(info):
        if line.startswith('|===='):
            first_line = ind
            break

    gpu_count = abs(space_ind - first_line) // 3
    pos = None
    for ind, line in enumerate(info):
        line = line.split()
        if len(line) > 1 and line[1] == 'Processes:':
            pos = ind + 2
            break
    gpu_usage = dict()
    if pos == None:
        return gpu_count, gpu_usage
    for i in range(pos, len(info)):
        line = info[i].split()
        if len(line) > 1:
            thread = line[2]
            gpu_id = int(line[1])
            if gpu_id not in gpu_usage:
                gpu_usage[gpu_id] = []
            gpu_usage[gpu_id].append(thread)
    return gpu_count, gpu_usage

def get_thread_info(thread_id: str):
    """根据thread_id获取thread详细信息"""
    id2user = get_user_id_map()
    thread_info = os.popen('ps -l ' + thread_id).read().split('\n')[1].split()
    thread_user = id2user.get(thread_info[2])
    thread_time = re.search('\\d+', thread_info[12]).group()
    thread_cmd = ' '.join(thread_info[13:])
    return dict(user=thread_user, use_time="{} hours".format(float(thread_time) / 60), thread_id=thread_id, cmd=thread_cmd)

def grep_gpu(task):
    """抢占GPU准备执行某个任务"""
    free_gpu = None
    while free_gpu is None:
        gpu_count, usage = nvidia_smi()
        time.sleep(2)
        for i in range(gpu_count):
            if i not in usage:
                free_gpu = i
                break
    print('free gpu found ! ', free_gpu)
    os.system(task)

def show():
    gpu_count, usage = nvidia_smi()
    for gpu_id in usage:
        usage[gpu_id] = [get_thread_info(thread_id) for thread_id in usage[gpu_id]]
    print('gpu count', gpu_count)
    print(json.dumps(usage, ensure_ascii=0, indent=2))

def run(gpu_id, task):
    os.environ['CUDA_VISIBLE_DEVICES'] = str(gpu_id)
    os.system('echo CUDA_VISIBLE_DEVICES:$CUDA_VISIBLE_DEVICES')
    os.system(task)

if __name__ == '__main__':
    print(sys.argv)
    if len(sys.argv) == 1:
        print("""
        GPU utility

        gpu show
        gpu grep your command here
        gpu 1 python haha.py
        """)
        exit(0)
    action = sys.argv[1]
    if action == 'show':  # 显示GPU使用情况
        show()
    elif action == 'grep':  # 争夺GPU，得到之后执行命令
        cmd = ' '.join(sys.argv[2:])
        print('grep gpu and run', cmd)
        grep_gpu(cmd)
    elif re.match("\\d+", action):  # 使用gpu_id执行某个action
        gpu_id = int(action)
        cmd = ' '.join(sys.argv[2:])
        print('run on gpu', gpu_id, 'cmd', cmd)
        run(gpu_id, cmd)
    else:
        print("unkown command")