TCP Socket Implementation On Golang

Golang is surely my first to go language to write web application, it hides many details but still gives a lot of flexibility. Recently I did strace to an http service app, actually did it without a reason but I found something interesting.

Here’s what strace -c gave me :

% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 91.24    0.397615         336      1185        29 futex
  4.13    0.018009           3      7115           clock_gettime
  2.92    0.012735          19       654           epoll_wait
  1.31    0.005701           6       911           write
  0.20    0.000878           3       335           epoll_ctl
  0.12    0.000525           1       915       457 read
  0.02    0.000106           2        59           select
  0.01    0.000059           0       170           close
  0.01    0.000053           0       791           setsockopt
  0.01    0.000035           0       158           getpeername
  0.01    0.000034           0       170           socket
  0.01    0.000029           0       160           getsockname
  0.01    0.000026           0       159           getsockopt
  0.00    0.000000           0         7           sched_yield
  0.00    0.000000           0       166       166 connect
  0.00    0.000000           0         3         1 accept4
------ ----------- ----------- --------- --------- ----------------
100.00    0.435805                 12958       653 total

There are a lot of interesting things in that profiling result, but the highlight of this article are the error number of read and the number of futex call

At the first sight I didn’t think about futex call, which most of them are a wake call. I thought that this app serve hundreds req per second, it should has many go routine; At the other hand it also leverage channel, it should has many under the hood blocking mechanism. So a lot of futex call should be normal, later I found out that this number was also from other things -will back to it later-. Continue reading

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Compiling Cocos2DX in Ubuntu Linux

Cocos2DX is one of most popular game engine in the world and it supports almost all popular platform available. Here is how we can compile cocos on Ubuntu Linux.

  1. Compiling Cocos2DX in ubuntu linux
    Download cocos from http://cocos2d-x.org
  2. Prepare dependencies :
    libx11-dev
    libxmu-dev
    libglu1-mesa-dev
    libgl2ps-dev
    libxi-dev
    g++-4.9
    libzip-dev
    libpng12-dev
    libcurl4-gnutls-dev
    libfontconfig1-dev
    libsqlite3-dev
    libglew-dev
    libssl-dev
    glfw3

    Go to /build directory inside cocos package
    run :

    sudo ./install-deps-linux.sh
  3. Create makefile
    mkdir lxbuild
    cd lxbuild
    cmake ../
  4. compile
    make

Now you can check lxbuild directory for some compiled library.

Enable bash auto completion in cygwin

Just like bash in native unix environment, cygwin’s bash also support auto completion but somehow cygwyn doesn’t come with bash package. In my case the auto completion was not enabled yet, so I need to enable.

Check if you have /etc/bash_completion, then add it to your /etc/bash.bashrc

add this line

. /etc/bash_completion

or you for your safety add conditional check beforehand

if [-f /etc/bash_completion]; then
. /etc/bash_completion
fi

restart you bash and try to use your magic tab key.

 

Great Terminal Emulator

My daily work before joining gameloft is mainly with linux environment and like another linux user I use terminal emulator frequently. However I must admit that there are big cons when we use terminal for daily activity, the main issue is our discover-ability of function. In GUI paradigm discover-ability is not a question, if we don’t know about a feature -we probably need- just take a look at App UI and we will find something. We hardly rely to experience and search engine to know a feature we need and we haven’t known.

That’s why I’m really thrilling with http://finalterm.org/ , it will help us to maximize our unix terminal’s powers.