• Linux,  Work

    Leap second causing ksoftirqd and java to use lots of cpu time

    Today there was a leap second at 23:59:60 UTC. On one of my systems, this caused a high CPU load starting from around 02h00 GMT+2 (which corresponds with the time of the leap second). ksoftirqd and some java (glassfish) process where using lots of CPU time. This system was running Debian Squeeze with kernel 2.6.32-45. The problem is very easy to fix: just run # date -s "`date`" and everything will be fine again. I found this solution on the Linux Kernel Mailing List: http://marc.info/?l=linux-kernel&m=134113389621450&w=2. Apparently a similar problem can happen with Firefox, Thunderbird, Chrome/Chromium, Java, Mysql, Virtualbox and probably other processes. I was a bit suprised that this problem…

  • Linux,  Work

    Linux performance improvements

    Two years ago I wrote an article presenting some Linux performance improvements. These performance improvements are still valid, but it is time to talk about some new improvements available. As I am using Debian now, I will focus on that distribution, but you should be able to easily implement these things on other distributions too. Some of these improvements are best suited for desktop systems, other for server systems and some are useful for both.

  • Linux,  Uncategorized

    Linux kernel: The battle of the CPU schedulers

    Since some time already, different patches are being written for the Linux kernel, which improve the CPU scheduler. The CPU scheduler, is that part of the kernel, that’s responsible for assigning CPU time to the different task running on your system. If you sometimes experience problems with sound stuttering or your mouse becoming jerky while running other CPU intensive tasks, then this is definitely a problem caused by the task scheduler. Con Kolivas has been maintaining an alternative scheduler for some time. His Staircase scheduler was designed with interactivity in mind, especially for desktop systems, where people want their system to be quickly responsive under all kinds of workloads. This…

  • Linux,  Mandriva

    Struggling with Linux’ OOM killer when building RPMs

    Last two weeks, I have created a lot of updated packages for Mandriva 2007.1. I packaged Gnome 2.18.1, and also updated subversion snaphots of kdepim and kdegraphics. Kdepim, because it has received a lot of bug fixing love the last two months, and kdegraphics, because it contains kpdf using new xpdf code, which should be compatible with PDF 1.6 and 1.7 specifications. In kdepim, they also removed the kitchensynk tool, which offered synchronization options with external devices. Apparently it was too buggy to be really useful. I have the impression that Kmail is indeed also more stable than in 3.5.6. I could not reproduce yet the hangs I sometimes experienced…