5. Understanding RT by graphics

   A lot of people seem not to understand very well what real-time means. They usually tend to think RT has anything to do with performance and the raw throughput. It doesn’t. It’s all about determinism and guarantees.

   This post’s title has “by graphics” words. I think the graphics below are worth a thousand words. I obtained them while porting the RT tree to Freescale boards some weeks ago at ProFUSION. Basically I’m running a task that wakes up every 40ms, run a tiny job, send some numbers through the network and sleeps again. The time in …

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6. Embedded Linux Conference 2010

   So, today was the last day of the Embedded Linux Conference. Now, I’ll be here in USA for the Linux Collaboration Summit. It was really cool and it was amazing to meet people you are only used to chat, exchange some emails or that you heard about. Just to name some: Steven Rostedt, Greg Kroah-Hartman, Frank Rowand, Mike Anderson, Andrew Morton, Jon Corbet and others. I was really impressed too seeing Rostedt programming or Greg answering emails. What a great guys

   And yesterday I presented my work, talking about the optimization of the Linux scheduler for soft real-time when …

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7. Banco do Brasil + Linux 64 bits

   Faz 1 mês mais ou menos que liguei no Banco do Brasil reclamando que a “solução de segurança” do site deles não estava funcionando no meu Linux 64 bits. Sem grandes surpresas, depois de me perguntarem se eu tinha a VM java da sun instalada, versão, etc, eles me passaram para o suporte de segundo nível. Pediram o meu telefone, dizendo que entrariam em contato (isso foi no sábado).

   Logo na segunda-feira de manhã me ligaram e após mais um tempo conversando, ele disse: “o problema é que a nossa solução de segurança não é homologada para a jre 1 …

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8. Amazing kernel related blog

   Today while reading “posts” on Buzz and digging in my RSS reader, I found this blog: http://smackerelofopinion.blogspot.com/ made by an ubuntu engineer. How many amazing posts there are on this blog. Particularly interesting is the one about ACPI Debugging and the other about perf, the tool I posted about some days ago (although it covers just a tiny amount of things this tool is capable of).

   When I have some spare time I’ll try to use that first post to debug the ACPI on my buggy asus laptop, where temperature goes sometimes as high as 90 …

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9. Chromium

   After reading this post at “Linux Today” I decided to install the so expected Linux version of Chrome, the Google’s browser.

   As I use Arch Linux, I haven’t expected to have a compiled version linked directly by the chromium’s website. Instead, I was hoping Arch’s developers already packaged it. And, with no big surprises, they did. Just to clarify a thing before continuing: Chromium is the open source projected behind Chrome (which is not opensource).

   I’m not writing this post to repeat what’s already written there. So read it too. As opposed to his …

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10. Playing with your cache

    Another possible titles could be “how to really slow down your computer” or “why caches are so important in computer architectures”. I started playing with turning my cache on and off last week using Linux because there are some situations in which you have to know why a piece of software is not working as expected. A possible problem could be the well known cache trashing, in which the contents of the cache is thrown away very often. Turning it down may give an answer if this is really the problem since now even running very slowly this variable is …

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