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I think this has been reliably chalked up to the fact that windows firefox is built using PGO, linux currently is not. If setting up wine becomes a hassle, you

by ezy 18y ago

I think this has been reliably chalked up to the fact that windows firefox is built using PGO, linux currently is not. If setting up wine becomes a hassle, you might want to just try grabbing the source and building with PGO on (or grabbing a bin of 3.1)

smanek 18y ago
I'm a bit of a compiler neophyte but if profile guided optimizations yield such a drastic improvement, why doesn't Mozilla (or my distribution via their package manager) put out binaries that were compiled with PGO?
- krakensden 18y ago
  PGO is pretty new, and it's turned on for the current builds of Firefox 3.1. I'm guessing it wasn't enabled by Mozilla initially for the usual reasons of complex packaging problems and low manpower for the Linux version. Distribution packagers generally aren't that knowledgeable about what they package, but that probably isn't what's wrong in the specific case of Firefox, which gets a lot of attention. For Firefox, it's probably the fact that Mozilla has very specific software requirements, and distributors have been burned (http://www.0xdeadbeef.com/weblog/?p=368 http://www.0xdeadbeef.com/weblog/?p=368) in the past by ignoring them. So... distributions generally don't do much to change what they distribute as Firefox.
krakensden 18y ago
You're probably right, especially given that these seem to be pure-javascript benchmarks, where Linux shouldn't have any particular disadvantage. What this misses, and what is the real problem with Firefox on Linux, is rendering performance. XRender, as far as I know, is not quite where it should be. There are two ways to accelerate it, EXA and XAA, and their performance varies greatly by point release of each driver. Throw in compositing, with a different set of interactions across drivers and acceleration architectures, and the whole gamut of misconfigured distributions, and you get an unspeakable mess. It would be nice if X.org could finish undoing the damage of XFree86's latter days, and get the drivers stable enough that distributors could figure out how to package them properly. Then maybe somebody could do something about the generally unpleasant and slow Linux GUI experience.

by ezy 18y ago

smanek 18y ago

I'm a bit of a compiler neophyte but if profile guided optimizations yield such a drastic improvement, why doesn't Mozilla (or my distribution via their package manager) put out binaries that were compiled with PGO?

krakensden 18y ago
PGO is pretty new, and it's turned on for the current builds of Firefox 3.1. I'm guessing it wasn't enabled by Mozilla initially for the usual reasons of complex packaging problems and low manpower for the Linux version. Distribution packagers generally aren't that knowledgeable about what they package, but that probably isn't what's wrong in the specific case of Firefox, which gets a lot of attention. For Firefox, it's probably the fact that Mozilla has very specific software requirements, and distributors have been burned (http://www.0xdeadbeef.com/weblog/?p=368 http://www.0xdeadbeef.com/weblog/?p=368) in the past by ignoring them. So... distributions generally don't do much to change what they distribute as Firefox.

krakensden 18y ago

You're probably right, especially given that these seem to be pure-javascript benchmarks, where Linux shouldn't have any particular disadvantage. What this misses, and what is the real problem with Firefox on Linux, is rendering performance. XRender, as far as I know, is not quite where it should be. There are two ways to accelerate it, EXA and XAA, and their performance varies greatly by point release of each driver. Throw in compositing, with a different set of interactions across drivers and acceleration architectures, and the whole gamut of misconfigured distributions, and you get an unspeakable mess. It would be nice if X.org could finish undoing the damage of XFree86's latter days, and get the drivers stable enough that distributors could figure out how to package them properly. Then maybe somebody could do something about the generally unpleasant and slow Linux GUI experience.