On Sun, Jan 18, 2015 at 2:29 AM, Andrei Gherzan <[email protected]> wrote:
> Hello, > > On Fri, Jan 16, 2015 at 3:05 AM, J. Tang <[email protected]> wrote: > >> >> On 2015-01-15, at 04:06, Mike Looijmans <[email protected]> wrote: >> >> > -2- The CPU doesn't actually have floating point support and the kernel >> is emulating it for you. This allows the platform to run "hf" binaries, at >> a minor performance cost compared to completely doing the emulation in user >> space (libc). >> >> From my understanding, the Raspberry Pi (at least the model B, which is >> what I have) has an FPU. >> >> Would it hurt to at least mention in the top-level README of the >> meta-raspberrypi layer that a user could enable hard FP by setting the >> DEFAULTTUNE? >> >> > Definitely it wouldn't. But right now we have two options: > We can just throw a README line and that's it. > Or we can investigate a little to see if in our current setup we actually > use FPU instructions or not. Following Mike's answer I would definitely > think that we are in case 1 where the compile based on the CPU > configuration figures out that we can use FPU instruction on this CPU > architecture. Right now, as being on vacation, I can really test on > binaries by dissembling code and check it by hand. Anybody who can do it > and provide some feedback? As well, some bench-marking would really make > sense here. > It was confirmed on another thread ( https://lists.yoctoproject.org/pipermail/yocto/2015-January/023201.html) that there is no performance improvements while switching to HFP. This basically proves what Mike Looijmans described in (1). So, we are on the safe side with our current setup. -- *Andrei Gherzan*
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