On Fri, Sep 2, 2011 at 1:27 PM, Christian Robottom Reis kiko@linaro.org wrote:
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?
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.
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.
Fwiw, VFP and NEON share same registers.. so as long as Tegra2 has VFP, I think it could use hard-float. Are we supporting any armv7-a that doesn't have at least VFP?
Although I'm a bit lost on this topic, are we comparing non-hard-float-but-vfp-enabled (ie. fp op's not falling back to sw) vs hard-float? Or soft-float vs hard-float?
BR, -R
---------- Forwarded message ---------- From: Jim Huang jserv@0xlab.org Date: 7 August 2011 18:01 Subject: Re: Would you send me your hard float experiment results you presented in Budapest? To: Zach Pfeffer zach.pfeffer@linaro.org
2011/8/7 Zach Pfeffer zach.pfeffer@linaro.org:
Jim,
Thanks. Would it be possible to post them by the end of the day?
skia ->
Switch from VFP back to fixed scalar based calculation
Previous configuration enabled ARM VFP for scalar float, but VFP on ARM11 is not as powerful as VFPv3 or NEON.
Reference benchmark: Item Fixed based VFP-based ------------ ----------- --------- Draw Canvas 58.37 fps 58.40 fps Draw Circle 37.48 fps 22.93 fps Draw Circle2 17.14 fps 18.31 fps Draw Rect 17.62 fps 20.69 fps Draw Arc 24.79 fps 27.45 fps Draw Image 19.08 fps 18.73 fps Draw Text 29.22 fps 25.79 fps
Also, have you sync'd up with Mike? He wants to negotiate on your contract.
I sent mail to Mike already. I don't know how to proceed.
Thanks, -jserv
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