Fwd: Would you send me your hard float experiment results you presented in Budapest?

[Rob Clark]

On Fri, Sep 2, 2011 at 1:27 PM, Christian Robottom Reis <kiko at 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 at 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 at linaro.org>
>>
>>
>> 2011/8/7 Zach Pfeffer <zach.pfeffer at 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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>
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