python工具——Py-Spy详解编程语言

Py-Spy是Python程序的抽样分析器，可视化查看Python程序在哪些地方花了更多时间

1.安装

pip  install py-spy

验证安装是否成功

py-spy -h 
py-spy 0.3.3 
Sampling profiler for Python programs 
 
USAGE: 
    py-spy <SUBCOMMAND> 
 
OPTIONS: 
    -h, --help       Prints help information 
    -V, --version    Prints version information 
 
SUBCOMMANDS: 
    record    Records stack trace information to a flamegraph, speedscope or 
              raw file 
    top       Displays a top like view of functions consuming CPU 
    dump      Dumps stack traces for a target program to stdout 
    help      Prints this message or the help of the given subcommand(s)

从上面看到有三个子命令

　　record：生成火焰图

　　top：实时查看每个函数运行时间并统计

　　dump：显示每个python线程的当前调用堆栈

2.示例

main.py

from fastapi import FastAPI 
from pydantic import BaseModel 
app = FastAPI() 
 
class Item(BaseModel): 
    name: str 
    price: float 
    is_offer: bool = None 
 
@app.get("/") 
def home(): 
    return {"Hello": "World"} 
 
@app.get("/items/{item_id}") 
def read_item(item_id: int, q: str = None): 
    return {"item_id": item_id, "q": q} 
 
 
@app.put("/items/{item_id}") 
def update_item(item_id: int, item: Item): 
    return {"item_name": item.name, "item_id": item_id}

启动

uvicorn main:app --host 0.0.0.0

python工具——Py-Spy详解编程语言

（1）record

生成火焰图

 py-spy record -o profile.svg --pid 11004

在Ubuntu下会出现

　　Permission Denied: Try running again with elevated permissions by going ‘sudo env “PATH=$PATH” !!’

执行

 sudo env "PATH=$PATH" py-spy record -o profile.svg --pid 11004

python工具——Py-Spy详解编程语言

使用ab压力测试

ab -n 10000 -c 100 http://localhost:8000/

python工具——Py-Spy详解编程语言

生成的火焰图

python工具——Py-Spy详解编程语言

通过生成火焰图分析程序瓶颈，看图中最下方哪个峰顶是平的，程序的性能问题就可以从那入手去解决

（2）top

显示了在python程序中花费最多时间的功能的实时视图

py-spy top --pid 11004

python工具——Py-Spy详解编程语言

说明：　　

　　参数

按％Own排序：当前在该函数中花费的时间的百分比 
按％Total排序：函数及其子级中当前的时间百分比 
按OwnTime排序：函数中花费的总时间 
按TotalTime排序：该函数及其子项花费的总时间

　　通过OwnTime可以比较直接的看出程序运行中，所占比消耗时间最多的函数

https://github.com/benfred/py-spy

（3）dump

显示每个线程的调用栈

$ sudo env "PATH=$PATH" py-spy dump --pid 1615 
Process 1615: /usr/bin/python /home/baby/.local/bin/uvicorn main:app --host 0.0.0.0 
Python v3.7.9 (/usr/bin/python3.7) 
 
Thread 1615 (idle): "MainThread" 
    select (selectors.py:468) 
    _run_once (asyncio/base_events.py:1750) 
    run_forever (asyncio/base_events.py:541) 
    run_until_complete (asyncio/base_events.py:574) 
    run (uvicorn/server.py:48) 
    run (uvicorn/main.py:386) 
    main (uvicorn/main.py:362) 
    invoke (click/core.py:610) 
    invoke (click/core.py:1066) 
    main (click/core.py:782) 
    __call__ (click/core.py:829) 
    <module> (uvicorn:8) 
Thread 1624 (idle): "ThreadPoolExecutor-0_0" 
    _worker (concurrent/futures/thread.py:78) 
    run (threading.py:870) 
    _bootstrap_inner (threading.py:926) 
    _bootstrap (threading.py:890) 
Thread 1625 (idle): "ThreadPoolExecutor-0_1" 
    _worker (concurrent/futures/thread.py:78) 
    run (threading.py:870) 
    _bootstrap_inner (threading.py:926) 
    _bootstrap (threading.py:890) 
Thread 1626 (idle): "ThreadPoolExecutor-0_2" 
    _worker (concurrent/futures/thread.py:78) 
    run (threading.py:870) 
    _bootstrap_inner (threading.py:926) 
    _bootstrap (threading.py:890) 
Thread 1710 (idle): "ThreadPoolExecutor-0_3" 
    _worker (concurrent/futures/thread.py:78) 
    run (threading.py:870) 
    _bootstrap_inner (threading.py:926) 
    _bootstrap (threading.py:890) 
Thread 1711 (idle): "ThreadPoolExecutor-0_4" 
    _worker (concurrent/futures/thread.py:78) 
    run (threading.py:870) 
    _bootstrap_inner (threading.py:926) 
    _bootstrap (threading.py:890)

注：

　　如果在windows下，使用dump，会报错

>py-spy dump –pid 4644
Error: 函数不正确。 (os error 1)

原创文章，作者：奋斗，如若转载，请注明出处：https://blog.ytso.com/tech/pnotes/20444.html

python工具——Py-Spy详解编程语言

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