JS V8引擎

​​https://www.zhihu.com/question/27428135/answer/2085274297?utm_source=wechat_session&utm_medium=social&utm_oi=631484691027464192&utm_content=group2_Answer&utm_campaign=shareopn​​

JS V8优化，假如直接把JS代码解析成机器码，那么有两个问题1. 需要编译全量比较慢。2. 很多优化都做不了，比如耗的内存多（代码(5KB) --> 字节码(40KB) --> 机器码(10M)）

解决方法是: 引入一层字节码

优化点主要有

1. 可以做函数的预解析，函数A调用函数B可以先不展开函数B，延迟执行

2. 假如函数B是很简单的函数，可以inline（内联）到函数A中

3. 基于字节码优化

----3.1 变量逃逸分析，假如一个变量不是逃逸的，我们可以把它放去寄存器中（而不需要放去内存）

----3.2 内联，可以合并冗余代码

收发文件

接收端: nc -l -p 5555 > file_name

发送端: cat /tmp/a > nc ${ip} 5555

关于如何设计appid/uid等，让业务解决更方便

常见工程技巧

 

debug python CPU 100%

1. strace & py-spy: https://groups.google.com/g/libuv/c/opFk74lww7k?pli=1

----1.1 apt-get install strace

----1.2 pip install py-spy

py-spy 0.3.11
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

 

py-spy dump -ll --full-filenames -p 505


Process 505: python3 -m gevent.monkey --module xxx -k yyy -t 300 -w 1 -b :8888 main:app
Python v3.7.2 (/usr/local/bin/python3.7)

Thread 505 (active+gil)
    __callback (/usr/local/lib/python3.7/site-packages/gevent/selectors.py:130)
        Arguments:
            self: <GeventSelector at 0x7f31e3ecc588>
            events: 1
            fd: 52
        Locals:
            cur_event_for_fd: 1
    run (/usr/local/lib/python3.7/site-packages/gevent/hub.py:647)
        Arguments:
            self: <Hub at 0x7f31f3c50d08>
        Locals:
            loop: <gevent.libev.corecext.loop at 0x7f31f3c50ac8>
Thread 536 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f314a9c3468>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f314a9c3468>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f314a80c5c8>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f314aa2c4c8>
            task_queue_get: <method at 0x7f314aa2c3c8>
            task_queue_cookie: <_thread.lock at 0x7f314a9c3468>
            run_task: <method at 0x7f31f025bf08>
            task_queue_done: <method at 0x7f314aa95cc8>
Thread 537 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f314a9c35a8>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f314a9c35a8>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f314a80c678>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f314aa95648>
            task_queue_get: <method at 0x7f314aa95548>
            task_queue_cookie: <_thread.lock at 0x7f314a9c35a8>
            run_task: <method at 0x7f314aa954c8>
            task_queue_done: <method at 0x7f314aa95848>
Thread 538 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f314a9c3698>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f314a9c3698>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f314a80c728>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f314aa95d08>
            task_queue_get: <method at 0x7f314aa95888>
            task_queue_cookie: <_thread.lock at 0x7f314a9c3698>
            run_task: <method at 0x7f314aa95f88>
            task_queue_done: <method at 0x7f314aa950c8>
Thread 541 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f314a9c3788>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f314a9c3788>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f314a80c7d8>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f314aa94948>
            task_queue_get: <method at 0x7f314aa94088>
            task_queue_cookie: <_thread.lock at 0x7f314a9c3788>
            run_task: <method at 0x7f314aa88208>
            task_queue_done: <method at 0x7f314aa94a08>
Thread 542 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f314a9c3878>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f314a9c3878>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f314a80c888>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f314aa95308>
            task_queue_get: <method at 0x7f314aa95208>
            task_queue_cookie: <_thread.lock at 0x7f314a9c3878>
            run_task: <method at 0x7f314aa95188>
            task_queue_done: <method at 0x7f314aa95408>
Thread 543 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f314a9c3968>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f314a9c3968>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f314a80c938>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f314aa94bc8>
            task_queue_get: <method at 0x7f314aa94d88>
            task_queue_cookie: <_thread.lock at 0x7f314a9c3968>
            run_task: <method at 0x7f314aa94c08>
            task_queue_done: <method at 0x7f314aa94e08>
Thread 544 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f314a9c3a58>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f314a9c3a58>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f314a80c9e8>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f314aa95c48>
            task_queue_get: <method at 0x7f314aa95c08>
            task_queue_cookie: <_thread.lock at 0x7f314a9c3a58>
            run_task: <method at 0x7f314aa95b88>
            task_queue_done: <method at 0x7f314aa95b48>
Thread 545 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f314a9c3b48>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f314a9c3b48>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f314a80ca98>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f314aa94e88>
            task_queue_get: <method at 0x7f314aa94cc8>
            task_queue_cookie: <_thread.lock at 0x7f314a9c3b48>
            run_task: <method at 0x7f314aa94f08>
            task_queue_done: <method at 0x7f314aa95448>
Thread 8013 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f314a8410a8>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f314a8410a8>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f31e421ef68>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f31e1d45448>
            task_queue_get: <method at 0x7f314aafe188>
            task_queue_cookie: <_thread.lock at 0x7f314a8410a8>
            run_task: <method at 0x7f314ab03988>
            task_queue_done: <method at 0x7f314aafe208>
Thread 8075 (idle)
    wait (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:68)
        Arguments:
            self: <_Condition at 0x7f314a9aac50>
            wait_lock: <_thread.lock at 0x7f31ef62be40>
        Locals:
            gevent_threadpool_worker_idle: True
    get (/usr/local/lib/python3.7/site-packages/gevent/_threading.py:158)
        Arguments:
            self: <Queue at 0x7f314a9b73a8>
            cookie: <_thread.lock at 0x7f31ef62be40>
    run (/usr/local/lib/python3.7/site-packages/gevent/threadpool.py:187)
        Arguments:
            self: <_WorkerGreenlet at 0x7f31ef523eb8>
        Locals:
            task: None
            exc_info: <builtin_function_or_method at 0x7f31fb60a5a0>
            fixup_hub_before_block: <method at 0x7f31ef5d0d08>
            task_queue_get: <method at 0x7f31ef5c2508>
            task_queue_cookie: <_thread.lock at 0x7f31ef62be40>
            run_task: <method at 0x7f31ef5c2e48>
            task_queue_done: <method at 0x7f314aa38588>

 

 

​​设置自启动sock5代理​​​运行 ssh -qTfnN -D 7070 xx.xx.xx.xx
运行 ps -elf | grep ssh 确认有 ssh进程在监听7070端口.
启动 Startup Applications程序
将ssh -qTfnN -D 7070 xx.xx.xx.xx 新建成一个自动启动项.

 

通过命令行打开chrome：google-chrome --proxy-server=socks5://127.0.0.1:7070
此时的Chrome是可以FQ的，登陆后在插件Store搜索SwitchyOmega并安装。
配置插件，将Proxy设为socks5、127.0.0.1、7070端口。右上角图标设为AutoSwitch后可配置白名单列表来决定哪些域名走代理哪些直连。

 

ssh:

ServerAliveInterval 60  60s后，client发给server一段话

 

-q 静默模式

-T 禁止分配伪终端

-f 后台运行

-n 把 stdin 重定向到 /dev/null (实际上防止从 stdin 读取数据). 在后台运行时一定会用到这个选项. 它的常用技巧是远程运行 X11 程序. 例如, ssh -n shadows.cs.hut.fi emacs 将会在 shadows.cs.hut.fi 上启动 emacs, 同时自动在加密通道中转发 X11 连接. 在后台运行. (但是如果 要求口令或密语, 这种方式就无法工作; 参见 -f 选项.)

-N 不执行远程命令. 用于转发端口. (仅限协议第二版)

-p 指定端口

 

 

python中:

come

　　yy

　　　　__init__.py

　　　　aa.py

　　main.py

可以在main.py中，这样来导入aa（其中aa有fun和hello两个函数）

1、from yy.aa import fun   （注意不能使用from come.yy.aa import fun，无论come文件夹是否有__init__.py）

2、import yy.aa  （然后yy.aa.fun()）

3、import yy.aa as vimi （然后vimi.test）

 

-----------------

 

 

缓存的东西，缓存已经存在的最新的，就比较优秀