Wed, 10 Apr

Rails Tutorial

I finished chapter 1 of Rails Tutorial (for 4.0). Even in the first chapter, this tutorial tought me RVM, Bundler, Git and Heroku. I’m not sure an entirely new Rails programmer should learn such a lot of things before “hello world” but this tutorial would be nice if you have a mentor, or you are a mentor and want to teach someone about Rails.

Why Git is so fast

http://osdir.com/ml/git/2009-04/msg02667.html

For example most complete I think but still not fully complete Java implementation: JGit. I hope that JGit developers can tell us whether using higher level language affects performance, how much, and what features of higher-level language are causing decrease in performance. Of course we have to take into account the possibility that JGit isn’t simply as well optimized because of less manpower.

http://osdir.com/ml/git/2009-04/msg02670.html

Java is definitely higher than C, but you can do some pretty low-level operations on bits and bytes and the like, not to mention the presence of a JIT.

My point: I don’t think that Java can tell us anything special in this regard.

http://osdir.com/ml/git/2009-04/msg02688.html

Sure it can.

Peff I think made a good point here, that we rely on a lot of small tweaks in the C git code to get really good performance. 5% here, 10% there, and suddenly you are 60% faster than you were before. Nico, Linus, Junio, they have all spent some time over the past 3 or 4 years trying to tune various parts of Git to just flat out run fast.

Higher level languages hide enough of the machine that we can’t make all of these optimizations.

(…)

I saw the last email probably in Hacker News and just thought, “oh, C Git developers are crazy” but this entire thread was much more interesting than I thought.