[FOSS-GPS] RTKLib MIPS requirements?
Michele Bavaro
mic.bavaro at yahoo.co.uk
Tue Aug 14 02:31:33 PDT 2012
Hello Danny,
Thanks for the update... our objectives perhaps are different.
Raspberry-PI is useless for me as there is no commercial product
development path beyond it.
In addition, there is no challenge running a few instances of RTKLIB on
that, or Beagleboard, or Beaglebone.
;)
All the best,
Michele
On 14/08/2012 11:06, Danny Miller wrote:
> Since Raspberry Pi finally became available, I've moved away from an
> STM32F4 attempt. There's not much purpose to it.
>
> Raspberry takes some getting used to, I'm not very familiar with
> Linux. The Debian Squeeze release that was out when Pi was released
> became obsolete in mid-July with the much faster, friendlier Debian
> Wheezy release. This is important because Wheezy uses the Pi's
> hardware FPU, Squeeze did not, which is why it was so slow. RTKLIB
> needs that FPU.
>
> I was delighted to find that Debian readily recognized the Silabs
> CP2102 USB-to-serial bridge and even the uBlox GPS's USB port. And on
> the GPIO pins, it also has a serial port there which is supported by
> the OS.
>
> RTKRCV does compile with the GCC included in the Debian release.
> However, I'm a bit unclear on how to configure the setup (calling one
> GPS a static base station, for example), pass it the ports and what
> sort of messages I can expect out of it. There's not going to be any
> way to run the GUI version, I assume? Windows emulators like Wine
> will never run on the Pi.
>
> Danny
>
> On 8/14/2012 2:35 AM, Michele Bavaro wrote:
>> Hello Danny,
>>
>> Have you done any real progress with STM32F4 then?
>>
>> Best regards,
>> Michele
>>
>>
>>
>> On 03/05/2012 14:45, Danny Miller wrote:
>>> I remember seeing that a long time ago, but forgot about it. Hmm, it
>>> does have useful figures.
>>>
>>> The A8 at 600MHz would be capable of 1200 DMIPS. At 20% utilization
>>> for 10Hz GPS operation that would indicate 240 DMIPS used, and
>>> that's with the TMS320C64x DSP. However, AFAIK that's not a
>>> floating-point DSP core and I expect you'd have to do a lot of
>>> tinkering with the compiler to get it to send any math to the DSP
>>> core. I suspect it wasn't used. The article doesn't mention the
>>> TMS320C64x DSP except in the Beagle specs.
>>>
>>> The STM32F4 is capable of 210 DMIPs. Hmm, that's troubling. There's
>>> still overhead which hasn't even come into play yet. I would expect
>>> compiling to metal would be substantially more efficient but I don't
>>> KNOW that. Then again, it doesn't HAVE to be 10Hz, we could go with
>>> 5Hz operation, there's no law saying it has to be 10Hz. Plenty of
>>> overhead at that speed.
>>>
>>> Danny
>>>
>>> On 5/3/2012 1:04 AM, Michele Bavaro wrote:
>>>> Dear Danny,
>>>>
>>>> Sorry, I assumed that you read this paper
>>>> http://gpspp.sakura.ne.jp/paper2005/isgps_2009_rtklib_revA.pdf
>>>> before posting.
>>>> There you may find more details about RTKLIB computational load at
>>>> 10Hz.
>>>>
>>>> Best regards,
>>>> Michele
>>>>
>>>>
>>>> On 02/05/2012 23:08, Danny Miller wrote:
>>>>> Well correct me if I'm wrong but this seems to come down to how
>>>>> many flops it can do, the moving of variables and such is probably
>>>>> a minority of the processing. That's why I wanna focus on the
>>>>> flops requirement.
>>>>>
>>>>> How much resources does RTKLib consume on Beaglebone? Because BB
>>>>> being faster and capable of RTKLib still doesn't establish the
>>>>> processing requirements. Is it running at 60% core utilization or
>>>>> 5%?
>>>>>
>>>>> I did run RTKLib on my i7 Q 740 1.73GHz laptop and the utilization
>>>>> was basically nil. I really couldn't determine anything from
>>>>> that, the usage figure was too low to give a meaningful number,
>>>>> not when the capabilities are at least 100x greater. I mean if
>>>>> the usage was 10% on that i7 I could pretty well dismiss it
>>>>> working on a Cortex M4. IIRC it was like a single-digit or
>>>>> fractional % though and the OS can consume considerable resources
>>>>> managing the busses and displaying the maps and interfaces so that
>>>>> doesn't mean much.
>>>>>
>>>>> Raspberry PI would be nice, but I can't get ahold of one, much
>>>>> less will it be readily available at this time for widespread
>>>>> consumption if the application worked. I'm still uncertain if
>>>>> widespread, long-term, low-price distribution is gonna happen or
>>>>> just turn out to be vaporware. STM32F4, anybody CAN order one or
>>>>> a thousand and get them for $15 or better right now. Still got
>>>>> high hopes of course. Raspberry PI also wasn't designed with a
>>>>> lot of low-level hardware interfacing so it'd still require a
>>>>> daughterboard like the STM32F4 to interface with a rover's motors
>>>>> and sensors and all.
>>>>>
>>>>> Danny
>>>>>
>>>>> On 5/2/2012 3:40 PM, Michele Bavaro wrote:
>>>>>> Hi Danny,
>>>>>>
>>>>>> I strongly doubt that a STM32F4 will be able to run RTKLIB.
>>>>>> It's true that it runs on a beaglebone, but Cortex-A8 has around
>>>>>> 2MIPS/MHz and runs at frequencies close to 1GHz,
>>>>>> whereas a Cortex-M4 has 1.25MIPS/MHz and runs at frequencies up
>>>>>> to 150MHz: there is almost one order of magnitude.
>>>>>> In addition since the structure of rtkrcv is quite strongly
>>>>>> coupled with a Linux OS,
>>>>>> there will be a lot of effort required to port it to a lighter
>>>>>> RTOS, let go to bare metal code.
>>>>>>
>>>>>> But I don't want to discourage you.. if you think it's doable go
>>>>>> for it :)
>>>>>>
>>>>>> Best regards,
>>>>>> Michele
>>>>>>
>>>>>> On 02/05/2012 00:15, Danny Miller wrote:
>>>>>>> STM32F4 "demo board" uses an Arm Cortex m4. 32 bit, 210 DMIPs
>>>>>>> and a single-precision hardware FPU. I'm slightly unclear on
>>>>>>> the memory space it has on this specific board but it should be
>>>>>>> 192KB SRAM and 1MB flash. That's my porting plan.
>>>>>>>
>>>>>>> If it WORKS, it'll be a great system, these boards are absurdly
>>>>>>> cheap. It is several more orders of magnitude of capability
>>>>>>> than these 8bit PICs and such, but I don't understand the scale
>>>>>>> of the flops requirement of RTKLib. I know it's somewhere
>>>>>>> between "much more than any 8-bit controller could ever do" and
>>>>>>> "won't even make Intel i7 break into a sweat". And those are
>>>>>>> wildly different magnitudes. I don't know exactly where RTKLib
>>>>>>> 10Hz would be between those.
>>>>>>>
>>>>>>> And it's be running RTKLib and just some minor application
>>>>>>> (navigation and monitoring) code which will not be
>>>>>>> processor-intensive, and it's not using Linux or an RTOS. So
>>>>>>> there's not a significant overheat for other tasks and the
>>>>>>> overhead's timing can be managed predictably and accurately.
>>>>>>> Pretty much the core can either do it or it can't.
>>>>>>>
>>>>>>> Danny
>>>>>>>
>>>>>>> On 5/1/2012 4:43 PM, julio menezes wrote:
>>>>>>>> Hi Danny,
>>>>>>>>
>>>>>>>>
>>>>>>>>> I have a core with a hardware FPU, but it's only capable of
>>>>>>>>> doing Single floats, not Double. It is going to break
>>>>>>>>> things to implement the specified Double calcs with Single
>>>>>>>>> precision? I would assume so, but it's worth asking.
>>>>>>>>>
>>>>>>>> The RTKLIB author T.Takasu and A.Yasuda have ported RTKLIB to
>>>>>>>> a BeagleBoard which has an ARM Cortex-A8- with 1 GHz and
>>>>>>>> floating point, I do not know if double or single precision.
>>>>>>>>
>>>>>>>> I plan to move in this direction also, may be using a hardware
>>>>>>>> less powerful but cheaper.
>>>>>>>> Raspberry Pi
>>>>>>>> http://www.raspberrypi.org/faqs
>>>>>>>> The SoC is a Broadcom BCM2835.
>>>>>>>> This contains an ARM1176JZFS, with floating point, running at
>>>>>>>> 700Mhz, and a Videocore 4 GPU.
>>>>>>>>
>>>>>>>> I am waiting, anxiously, the RTKLIB 2.4.2 version with
>>>>>>>> RTCM-104 phase messages encoder to built a local base station
>>>>>>>> as where I live there are no near NTRIP network ( less than
>>>>>>>> 10km ).
>>>>>>>>
>>>>>>>> good luck,
>>>>>>>>
>>>>>>>> julio menezes
>>>>>>>>
>>>>>>>>
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