Taras’ Blog

Last week I learned about how Windows handles page faults backed by files (specifically xul.dll). I already knew that Linux was suboptimal in this area, perhaps the clever people at Redmond did better. Shaver pointed me at xperf, which is sort of like the new Linux perf tools. Xperf rocks in that it can capture [...]

Magic of GCC PGO On Friday I finally got gold to produce a prelinkable static binary(bug). I also got around to trying out GCC profile-guided-optimization with the debloatifying -freorder-blocks-and-partition option. This option breaks up every profiled function into cold and hot “functions”. It then lumps all of the hot functions together. PGO performance is amazingly [...]

Note: I am doing my measurements and experiments on Fedora 12, once I feel that I understand and can solve the problems on Linux, other operating systems will follow. The aim of this post is to document what I have learned about the mysterious process of loading programs from the filesystem perspective. A binary is broken [...]

Graphs Note: the following graphs broke on the nightlies this week. I would appreciate help with reducing this to a proper testcase. They work fine on older nightlies and released versions of Firefox. Non-spidermonkey JS engines wont work as they don’t support destructuring assignment and other goodies. Once I graphed my file-access logs, most of [...]

Dietrich blogged a “wake up and smell the startup” executive overview of startup issues caused by our extension practices. This post is a “numbers” followup. For this experiment I installed a brand-spankin-new copy of Linux Firefox 3.6. Firefox is installed on a 7200 hard drive, the rest of my system lives on an SSD. The [...]

I have been told that it should be possible to control the way the GNU linker lays out binaries. Unfortunately until recently I couldn’t figure out the right incantations to convince ld to do my bidding. Turns out what I needed was to be stranded on a beach in Fiji with nothing better to do [...]

Hunting Down Mythical “Slowness” I recently met a developer who used Chromium instead of Firefox. Chromium’s superior startup speed was his reason for using it.This got me excited because said developer was running Linux, so it was relatively easy to measure cold startup and get a complete IO breakdown. Turned out Firefox took roughly 23 [...]

I did some digging to figure out if one can setup cold-startup testing in Windows 7 without nasty hacks. My conclusion is: sorta-kinda. The Good – Most of the Ingredients Are Present I haven’t actively used Windows since pre-XP days. It looks like it has come a long way since then: there is now a [...]