David Mandelin's blog

I’ve been meaning for a while to write a post on how to interview software engineering candidates: here it is. In my opinion, there’s really no science to interviewing: it’s an intuitive, practice-based activity. So, as Barry Schwartz suggests in his book Practical Wisdom, I’m going to try to express what I know in just [...]

Yesterday I gave a talk at O’Reilly Velocity 2011, “Know Your Engines: How to make your JavaScript fast”. The concept came from the common idea that C++ programmers should know something about how the compiler works on their code in order to know how to get good performance. Why not for JS? So I basically [...]

Earlier this month, I got to fly to Indonesia to attend Firefox 4 release parties along with David Anderson and Josh Aas. (Gen Kenai, Luke Wagner, and Christian Legnitto also went to Indonesia, for “Leg 1″ just before we got there.) Sorry about blogging this so long after the fact–I’ve been recovering, catching up on [...]

So, JägerMonkey is done (as of last fall, really), and Firefox 4 is out (yay! and whew!), so that means we can get back to the fun stuff: new coding projects. At the Platform Work Week, we firmed up plans for JavaScript for the next year or so. The main themes are debugging and performance: [...]

This post is just a little tip for hacking Mozilla on Windows. It’s well known that the basic Windows console program is, uh, not good, compared to a Unix console. But it turns out there’s a really nice project on SourceForge named Console that provides multiple tabs, good fonts and scrollback, keyboard shortcuts, and a [...]

The V8 team has dropped Crankshaft, a new JIT system for JavaScript, into their bleeding-edge repo. According to their blog entry, it doubles their speed on 3 of 8 V8 benchmarks, and improves page load time by 12% on JS-heavy pages. First off: Congratulations to the V8 team. It looks like great work, pushing forward [...]

colinpj tweeted me “Can you post kraken results using the same browser versions + setup?” Here you go:

IEBlog recently showed some Sunspider results that show them currently ahead of us. I just want to correct that a little bit. :-) The latest Firefox shown on their graph is Firefox 4.0 beta 6, which is well behind our nightly releases at this point, including in performance. Their graph shows the Chrome 8 nightly, but [...]

At the beginning of this year, the Mozilla JavaScript team started a new project, code-named JägerMonkey, with a simple goal: make us fast. Our previous major engine upgrade, TraceMonkey, gave Firefox 3.5 a big speed boost. But while the technology inside TraceMonkey makes it faster than any other engine on certain programs (then and now), [...]

Just a quick note: I’m pretty busy these days getting JaegerMonkey ready to land. But I’m now sending out small status updates on my twitter account ‘dmandelin’.