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by Douglas Clifton.
Original Post: Cachegrind your Web apps
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Valgrind is a entire suite of open-sourcetools, including basic debugging, profiling, and more advanced techniques such as threading, memory management, and leak detection. For the purposes of this article, I will focus on Cachegrind, and in particular within the domain of Web applications. Although there are a number of developers contributing to Valgrind, Julian Seward is the original designer and author.
Out of the three server-side languages I am most familiar with, PHP seems to be the one that is best represented, with some Python—but I found very little if any information on Perl.
What is Cachegrind?
Cachegrind is an Intel CPU emulator and cache profiler that performs detailed simulations of the onboard I1, D1 and L2 caches and can accurately pinpoint the sources of cache misses in your code. It identifies the number of cache misses, memory references, and instructions executed for each line of source code. (paraphrased)
Xdebug
Xdebug is the tool of
choice for PHP developers when it comes to standard debugging, and the built-in Profiler with Cachegrind output is also maturing. Typically the output is in a file named cachegrind.out.pid, which is plain text, but be careful with large, complex applications as it can grow to on the order of 500MB. The raw data is almost useless, to really analyze and visualize the results you need a parsing/graphing tool. There are several available depending on your platform and needs.
Viewers
Once you have your output you need an application to make sense of it. Listed below are solutions for Linux (or any Unix-like OS running KDE), Mac OS X, Windows, and even a browser-based solution from Google Code.
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Valgrind is a entire