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I spent last week in Ottawa for this years Ottawa Linux Symposium along with my fantastic Belgian boss and a flotilla of Linux aficianados. I’m told the attendance this year came in at a good eight hundred which seems like quite a bit to those of us who stumbled through the first. I think they had it right back then — minimize the casualties incurred during nonsensical talks.
This year, my first visit after a long hiatus, was also my first time attending the Kernel Summit which has preceded the main conference for the last few years. I’m still not entirely sure what to make of it. I was very encouraged by some clear-thinking shining stars and somewhat discouraged by some poo-slinging children. On balance I think I’d have to say that the people worth listening too outnumbered the destructive vocal minority. Just like any non-trivial group of people, I suppose. I’m told that this year’s was not as exciting and contentious as previous years and I could certainly buy that. I was particularly glad to see Linus sitting down to a Mercurial demo with Matt. Here’s to hoping.
As for the main conference, I really enjoyed Ian Pratt’s talk on Xen — and not just because Robert now works for Xensource. I have only been admiring Xen from the periphery so it was quite interesting to see how it really gets things done, particularly the page sharing business. Its domain migration business also looks pretty exciting. There was a great moment during his talk when he showed a graph of some web benchmark that ran while the domain with the web server was transparently being migrated between machines. Migration’s problem can be basically narrowed down to trying to keep pages in sync between the old and new host while the task is actively dirtying new pages. It employes this clever algorithm where it allows itself to consume, say, 10% of the system migrating pages, hopefully at a higher rate than the task can dirty them. Eventually there will be such a small amount of pages dirty left that the task can be stopped and finally migrated to the new host with a small amount of down time. The graph of the throughput of the web benchmark during the migration showed exactly this. There was a stable degredation of the throughput down 10% for a few seconds and then a painless few milliseconds of idle while the task hoped over to the new host. I only remember this, and apologize for wandering through it with you, because the audience broke into spontaneous applause at the slide. When’s the last time you heard of that happening? Not sarcastic “haha, the IA64 doesn’t have ISA” applause — real honest-to-god “holy crap, it Just Works” applause.
I was more actively involved in an AIO BOF later on in the conference that seemed to go pretty well. We spent a fair amount of time worrying about how to really demonstrate the benefits of buffered filesystem AIO interfaces. Samba’s use will help, but that might not be enough. There was also a pretty interesting revivial of the O_STREAMING discussion which seems to come up every few years. This time there was a interesting twist, mostly driven by sct, involving directories and alleviating dcache pressure. I might see if I can find some time to whip together an implementation, we’ll see.
Primarily, though, it was just good fun to reconnect with friends that I hadn’t seen in ages. Jes and I got to talk quite a bit about home ownership and msw made sure to point out how old and ridiculous my various techy toys are. Good times! Being in Ottawa also provided a great excuse to hang out with Deb and Rob. I got to spend some time in their lovely apartment in the Glebe hanging out with their kitties, eating fun food, and playing way too much ogame. I wish all my friends lived in one place. And that it was a good place. And that I lived there, too.
To top it off, United bumped me up into first on the long leg back from O’Hare as part of some grand seat shuffling arrangement to get a family seated together. To all the unruly families who usually make traveling on summer weekends as enjoyable as eating ones own face, I take it all back — cheers!