2011/9/3 Christian Robottom Reis kiko@linaro.org:
On Tue, Aug 30, 2011 at 11:24:59AM -0500, Zach Pfeffer wrote:
I'd like you to meet Jim who did the initial hardfloat work. This email contains the results that Jim produced.
Hmm, but the email seems to not actually contain a hard-float run. Or am I misreading what he means by Fixed vs VFP?
hi kiko,
In fact, the presentation was incomplete. That is exactly the reason why I didn't want to make it public.
The original plans were as following: - Analyze skia and webkit for soft/hard-fp - Select fixed-point, soft-vfp, and hard-fp implementations in skia and then check the benchmark results.
However, I didn't make all benchmark results ready when I built with hard-fp. I didn't know why and stopped the study due to personal reasons. (sorry for being absent)
I believe that the conclusion was that skia and webkit may benefit, but that such benefits would impose an undue burden on Android's distribution model which tries to create libs that can run on as many architectures as possible.
You may be confusing things here. Hard-float is a pure software ABI change, and any platform which supports VFP can use it if you build it that way. However, since it is an ABI change it requires that hard-float libraries be available.
Yes, since ABI has to be changed, we have to confirm the modifications against existing components: - dalvik fast-interpreter and jitter - v8 compiler/evaluator - android software OpenGL|ES renderer
Again, please don't be too serious about my incomplete materials. I didn't have enough time to analyze that time.
What /would/ stop code from running on certain platforms is using NEON (it would exclude the Tegra2 and some existing Marvell v7s). But that doesn't seem to be in question here.
Regards, -jserv