Long long ago, when I was first learning how to compile Mozilla from source, through some magical process I ended up with a .mozconfig file which worked. Maybe I copied it from DevMo, or maybe someone gave me their copy. I really don’t remember!
Anyway, now that the build process is ever-so-slightly more familiar to me, I’ve cleaned up some of the .mozconfig files I have around. One line I just looked at was:
mk_add_options MOZ_CVS_FLAGS=@CVS_FLAGS@' -q -z4'
The -z4 specifies the compression level used when transferring the source. Using 0 disables compression, and 9 uses maximal compression. In theory, it’s a tradeoff between CPU time and network speed. So what’s the best value to use?
A quick benchmark seems to indicate that it doesn’t matter. -z4, -z8, and -z9 all took 135 seconds (+/- a couple seconds) to checkout the Firefox 3 trunk code. A test with -z0 was about 10 seconds slower, but I didn’t repeat it to see if it was a quirk.
So, I’m just going to remove this line from my .mozconfig, and rely on the default (which is “-q -z3″). Yay simplicity. Anyone else find similar results? Perhaps -z9 helps for dialup-speeds? [My system is a 2.16Ghz Macbook Pro, connected over 802.11g WiFi.]