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  Circumventing browser connection limits for fun and profit

A few days ago, this video hosted by metacafe popped up on digg, explaining how to increase site download times by tweaking your browser settings to increase connection parallelism. To explain why this works, let’s step back a bit to discuss how browsers manage server connections. In building any application, developers are often required to make ‘utilitarian’ choices. Pretentiously paraphrasing Jeremy Bentham, ‘utilitarian’ describes an approach that â...

   HTTP,Concurrent connection limit,Solution,AJAX     2011-12-14 13:01:02

  Optimization Tricks used by the Lockless Memory Allocator

With the releasing of the Lockless Memory Allocator under the GPL version 3.0 license, we can now discuss more of the optimization tricks used inside it. Many of these are things you wouldn't want to use in normal code. However, when speed is the ultimate goal, sometimes we need to break a few rules and use code that is a little sneaky.The SlabA slab is a well-known technique for allocating fixed size objects. For a given object size, a chunk of memory is divided up into smaller regions of that ...

   Optimization,Memory allocation     2011-11-16 08:02:16

  5 Ways to Boost MySQL Scalability

There are a lot of scalability challenges we see with clients over and over. The list could easily include 20, 50 or even 100 items, but we shortened it down to the biggest five issues we see.1. Tune those queriesBy far the biggest bang for your buck is query optimization. Queries can be functionally correct and meet business requirements without being stress tested for high traffic and high load. This is why we often see clients with growing pains, and scalability challenges as their site becom...

   MySQL,Scalability,Methods,Implementation,Practice     2011-10-18 02:57:27

  Python internals: how callables work

[The Python version described in this article is 3.x, more specifically - the 3.3 alpha release of CPython.] The concept of a callable is fundamental in Python. When thinking about what can be "called", the immediately obvious answer is functions. Whether it’s user defined functions (written by you), or builtin functions (most probably implemented in C inside the CPython interpreter), functions were meant to be called, right? Well, there are also methods, but they’re not very ...

   Python,Callable work,Rationale     2012-03-24 05:20:27

  What's Wrong with the For Loop

Closures in Java are a hot topic of late. A few really smart people are drafting a proposal to add closures to a future version of the language. However, the proposed syntax and the linguistic addition are getting a lot of push back from many Java programmers. Today, Elliotte Rusty Harold posted his doubts about the merits of closures in Java. Specifically, he asks "Why Hate the for Loop?": I don’t know what it is some people have against for loops that they’re so eager to...

   For loop,Basic,Problem,Efficiency,Java     2012-02-24 05:06:15

  Obviously Correct

What do automatic memory management, static types and purity have in common? They are methods which take advantage of the fact that we can make programs obviously correct (for some partial definition of correctness) upon visual inspection. Code using automatic memory management is obviously correct for a class of memory bugs. Code using static types is obviously correct for a class of type bugs. Code using purity (no mutable references or side effects) isobviously c...

   Memory management,Code,Static,Purity     2011-11-07 08:13:05

  The most stupid C bug ever

I have been programming for a number of years already. I have seen others introduce bugs, and I have also introduced (and solved!) many bugs while coding. Off-by-one, buffer-overflow, treating pointers as pointees, different behaviors or the same function (this is specially true for cross-platform applications), race conditions, deadlocks, threading issues. I think I have seen quite a few of the typical issues. Yet recently I lost a lot of time to what I would call the most stupid C bug in my ca...

   C,Bug,Stupid,Bug code,All     2011-08-26 02:37:29

  The most stupid C bug ever

I have been programming for a number of years already. I have seen others introduce bugs, and I have also introduced (and solved!) many bugs while coding. Off-by-one, buffer-overflow, treating pointers as pointees, different behaviors or the same function (this is specially true for cross-platform applications), race conditions, deadlocks, threading issues. I think I have seen quite a few of the typical issues. Yet recently I lost a lot of time to what I would call the most stupid C bug in ...

   C,Bug,Comment,Back slash     2012-04-22 03:40:49

  The ugliest C feature:

<tgmath.h> is a header provided by the standard C library, introduced in C99 to allow easier porting of Fortran numerical software to C. Fortran, unlike C, provides “intrinsic functions”, which are a part of the language and behave more like operators. While ordinary (“external”) functions behave similarly to C functions with respect to types (the types of arguments and parameters must match and the restult type is fixed), intrinsic functions accept arguments of...

   C,,Fortran,Intrinsic functions,C99,Ugly     2011-12-26 08:33:27

  Significance and use of do{...}while(0)

In some Linux kernel and other open source codes, we can see some codes like below: do{ ... }while(0) This code snippet is not a loop, it seems there is no significance of using do...while this way, then why should we use it? In fact, the significance of do{...}while(0) is better than optimizing your code. After some research, we summarize some benefits of it. 1. Help define complex macro to avoid error #define DOSOMETHING()\ foo1();\ foo2(); The me...

   do{...}while(0), optimization     2012-10-21 21:13:22