Monday Jul 17, 2006

Just like running Windows

I'm in Ottawa for the 2006 Desktop Developer's Conference. I got here last night, about 3 hours later than originally planned - the first time our plane pulled out of the gate in Chicago they noticed a big crack in a tire on the front of the plane that they couldn't see during the pre-flight check because it was on the part of the tire touching the ground. A quick return to the gate was called for, and we sat on the plane for about 15 minutes while they jacked up the front and popped on a spare.

Our second try at takeoff we made it all the way out to the taxiway and were next in line for takeoff, but then sat and sat. Eventually the pilot got on the intercom and said that due to the previous plane “using too much power” our plane's on-board computer was malfunctioning. (I'm not quite sure how that happens - was everyone on the other plane pointing their portable electronic devices at us?) Another trip back to the gate so the maintenance crew could get on board and scratch their heads over it. One of them must have been an MCSE, because the next announcement was that they were going to try to fix the computer by power cycling it. And since it was so integrated into the plane, that meant shutting down the power to the entire aircraft, leaving us in the dark for a couple of minutes and then booting the plane back up.

Fortunately, the reboot fixed the problem, and the third time we left the gate we finally got to take off.

Tuesday Jul 19, 2005

DDC Talk: "Peeking under the Hood"

I've just finished my tutorial presentation on tools for tracing X server/client interactions here at the Desktop Developer's Conference in Ottawa. I've posted both the slides from my talk and the DTrace probes and scripts I showed as one of the tools.

Unfortunately, I didn't get to cover all the tools I wanted to (mostly because I spent a lot more time in the last week on getting the Xorg 6.9 & 7.0 releases ready for their slightly delayed Release Candidate Zero milestones than on my presentation). There are some tools we've developed for our own use in the X group in Sun I was hoping to be able to release before the talk and cover, but didn't get around to - such as a tool that uses the X-Record extension to generate statistics on the number of times each request is called, which we used when switching from CDE to GNOME to determine which parts of the server needed more optimization attention now (Motif & GTK have very different call profiles - for instance, GTK is much more image/pixmap based than Motif was, while Motif use lots of filled rectangles and straight lines to draw it's window decorations and widgets).

About half the talk, and most of the interest though, was in the dtrace probes in the X server (which I wrote about in previous posts). A lot of what I showed was doable before, and in many cases, has been done before, but took much more work. For instance, the X Record program I wrote earlier, and an even older program that post-processed xscope output to produce call counts, both gave counts of the number of times a function was called, but they were a lot more work to write than the simple requests.d script. And that script was easily extended to time-requests.d to instead print the average CPU time the X server took to process each request.

Tip for giving presentations using StarOffice 7 in JDS 3 on Solaris 10: When you want to switch from slide show mode to another window to run a demo, exit slide show mode first in StarOffice, and then switch apps. Trying to Alt-Tab directly did amuse my audience (especially the author of an alternative window manager watching from his comfy spot on the couch), but discovering StarOffice/Metacity interaction bugs during a presentation to a less forgiving audience may not be the best demo of our "integrated" desktop. Fortunately, pkill soffice worked well in the terminal window I had switched to.

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Engineer working on Oracle Solaris and with the X.Org open source community.


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