Mac OS X Secretly Cripples Non-Apple Software
spikedLemur writes "Vladimir Vukicevic of the Firefox team stumbled upon some questionable practices from Apple while trying to improve the performance of Firefox. Apparently, Apple is using some undocumented APIs that give Safari a significant performance advantage over other browsers. Of course, "undocumented" means that non-Apple developers have to try and reverse-engineer these interfaces to get the same level of performance. You really have to wonder what Apple is thinking, considering the kind of retaliation Microsoft has gotten for similar practices.
David Hyatt
;)
Feb 28th, 2008 at 1:24 pm
The programmatic disabling of coalesced updates should not be public API. It's actually a very dangerous thing to do. We aren't really happy with that code in WebKit, but we had to do it to avoid performance regressions in apps that embedded WebKit. Technically it's wrong though, since we turn off the coalesced updates for any app that uses WebKit! This includes drawing they do that doesn't even use WebKit.
As for the window display throttling, that was a pref designed for Safari (that we don't even use any more). It's not private or magic. It's nothing more than a pref that we can examine from Safari-land, so linking to that is just silly.
Many of the private methods that WebKit uses are private for a reason. Either they expose internal structures that can't be depended on, or they are part of something inside a framework that may not be fully formed. WebKit subclasses several private NSView methods for example, and it cost us many many man hours to deal with the regressions caused by the internal changes that were made to NSViews in Leopard.
As you yourself blogged, there was a totally acceptable public way of doing what you needed to do.
For any private methods we use that we think should be public, we (the WebKit team) file bugs on the appropriate system components. Many of these methods have become public over time (CG stuff in Leopard for example). Be careful when you dig into WebKit code, since we may continue to use the WK method even though it's not public API just because we need to work on Tiger.
The Safari performance improvements are coming in Safari 3.1, not yet available to the public. To see them today, you have to be running current WebKit nightlies. The difference between the new WebKit builds and vanilla Safari 3.0.4 is pretty dramatic.
The Slashdot summary is accusing Apple of reserving the tasty bits for safari, but the article shows that it's webkit not safari that knows the shorcuts. Anyone is free to use webkit. it's apples optimized interface for applications. If Firefox chooses not to use it well I can understand why but they need to accept that their interface may not be as optimized.
Indeed what apple is doing does not seem that out of whack. They have an interface that is optimized for stability not speed. That's the proper way to do it. and they figure out how one can tweak it for speed. Do you make that the defaults or do you put those in a container like webkit where one can manage the tradeoffs better? duh...
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