Debugging Java performance problems presentation
I recently gave a presentation at the local UNIX users group titledDebugging Java performance problems. The presentation describes various opensource tools and how they can be used to understand what is causing CPU, memory and lock contention issues inside a Java virtual machine. If there are additional tools not discussed in the presentation that you find useful for debugging Java performance problems, please let me know through the comment feature.
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Slashdot and other sites had mention of the release of the 2.6.27 Linux kernel today. Some of the new features in the kernel come from the KernelNewbies Linux 2.6.27 notes about improved SMP support for the page cache: The page cache is the place where the kernel keeps in RAM a copy of a file to improve performance by avoiding disk I/O when the data that needs to be read is already on RAM. Each "mapping", which is the data structure that keeps track of the correspondence between a file and the page cache, is SMP-safe thanks to its own lock. So when different processes in different CPUs access different files, there's no lock contention, but if they access the same file (shared libraries or shared data files for example), they can hit some contention on that lock…
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I have been a long time Cowboy Mouth fan, and still remember the first time I saw them play a concert in Delaware. They had an incredible amount of energy, and where one of the few bands I had seen that wanted the crowd involved in every aspect of the show. When I heard they were playing one of the local festivals here in town, I decided to venture out with a few friends to see them. The show started off like all Cowboy Mouth shows with a ton of energy, and the lead singer (who also plays drums) jamming on drums to get the crowd into the show…
$ read more →Finding a file's package name offline in Fedora without yum whatprovides
One really cool feature of ubuntu is the command-not-found script. If you try to execute a program, say, nmap -- and that dpkg hasn't been installed, the command-not-found script executes to parse a locally installed database to suggest, "hey, you should try executing # apt-get install nmap" or something similar. This really makes ubuntu more user friendly. Fedora has the ability to use " # yum whatprovides <>" but yum is going to bomb out if you don't have a working network connection…
$ read more →The best website ever
Oh my gosh, this is the funniest (and coolest) site I have seen in a LONG LONG time!
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