调优
####


Python Tracebacker
==================

* 要启用这个回溯器，你需要添加选项 ``py-tracebacker=<socket>``,，其中，``<socket>`` 是已创建 UNIX socket 的 ``basename``
* 如果你有 4 个 uWSGI worker，并且添加了 ``py-tracebacker=/tmp/tbsocket``，那么将会创建名字从 ``/tmp/tbsocket1`` 到 ``/tmp/tbsocket4`` 的 4 个 socket。
* 连接到其中任意一个都将会返回 worker 中运行的线程的当前回溯。
* 你可以使用你最喜欢的应用或方法来连接到那些 socket，但是 uWSGI 有一个供你使用的方便的选项 ``connect-and-read`` ::

    uwsgi --connect-and-read /tmp/tbsocket1




写一个名为 ``slow.py`` 的蠢蠢的测试应用::

    import time

    def dormi():
      time.sleep(60)

    def dormi2():
      dormi()

    def dormi3():
      dormi2()

    def dormi4():
      dormi3()

    def dormi5():
      dormi4()

    def application(e, start_response):
      start_response('200 OK', [('Content-Type', 'text/html')])
      dormi5()
      return "hello"


运行::

    $ uwsgi --http :8080 -w slow --master --processes 2 --threads 4 --py-tracebacker /tmp/tbsocket.
    *** uWSGI is running in multiple interpreter mode ***
    spawned uWSGI master process (pid: 8955)
    spawned uWSGI worker 1 (pid: 8956, cores: 4)
    spawned uWSGI worker 2 (pid: 8957, cores: 4)
    spawned uWSGI http 1 (pid: 8958)
    python tracebacker for worker 1 available on /tmp/tbsocket.1
    python tracebacker for worker 2 available on /tmp/tbsocket.2


创建一堆到它的请求::

    curl http://localhost:8080 &
    curl http://localhost:8080 &
    curl http://localhost:8080 &
    curl http://localhost:8080 &


当这些请求运行的时候 (每个都会花费几乎一分钟来完成)，你就可以检索回溯::

    ./uwsgi --connect-and-read /tmp/tbsocket.1
    ./uwsgi --connect-and-read /tmp/tbsocket.2

回溯器的输出将会是这样的::

    *** uWSGI Python tracebacker output ***

    thread_id = uWSGIWorker1Core1 filename = ./slow.py lineno = 22 function = application line = dormi5()
    thread_id = uWSGIWorker1Core1 filename = ./slow.py lineno = 14 function = dormi5 line = def dormi5(): dormi4()
    thread_id = uWSGIWorker1Core1 filename = ./slow.py lineno = 13 function = dormi4 line = def dormi4(): dormi3()
    thread_id = uWSGIWorker1Core1 filename = ./slow.py lineno = 12 function = dormi3 line = def dormi3(): dormi2()
    thread_id = uWSGIWorker1Core1 filename = ./slow.py lineno = 11 function = dormi2 line = def dormi2(): dormi()
    thread_id = uWSGIWorker1Core1 filename = ./slow.py lineno = 9 function = dormi line = time.sleep(60)

    thread_id = uWSGIWorker1Core3 filename = ./slow.py lineno = 22 function = application line = dormi5()
    thread_id = uWSGIWorker1Core3 filename = ./slow.py lineno = 14 function = dormi5 line = def dormi5(): dormi4()
    thread_id = uWSGIWorker1Core3 filename = ./slow.py lineno = 13 function = dormi4 line = def dormi4(): dormi3()
    thread_id = uWSGIWorker1Core3 filename = ./slow.py lineno = 12 function = dormi3 line = def dormi3(): dormi2()
    thread_id = uWSGIWorker1Core3 filename = ./slow.py lineno = 11 function = dormi2 line = def dormi2(): dormi()
    thread_id = uWSGIWorker1Core3 filename = ./slow.py lineno = 9 function = dormi line = time.sleep(60)