STM32F7 process is too slow.

[Vicky-S]

I ran the Wheatstone benchmarking and the result is below

Loops: 1000 Iterations: 1 Duration: 9781 millisec. C Converted Double Precision Whetstones: 10.22 MIPS

Actually STM32F7 is 216MHz processor but it looks like its not running that fast in official core.

[Vicky-S]

Actually this issue was already adressed and sorted out in STM32GENERIC. I shared the link below for your reference.

https://github.com/danieleff/STM32GENERIC/issues/14

[Vicky-S]

Actually its not a complaint. I just want let you know that this type of issue was there in GENERIC and its sorted out so that we can do the same in official core for fast processing.

[fpistm]

FPU is already enabled for F7 so not link to issue raised in STM32GENERIC.

Hereafter, my test result:

STM32GENERIC (using -Os) Loops: 1000 Iterations: 1 Duration: 2947 millisec. C Converted Double Precision Whetstones: 33.93 MIPS

STM Core (using -Os) Loops: 1000 Iterations: 1 Duration: 10084 millisec. C Converted Double Precision Whetstones: 9.92 MIPS

I already know the difference and I've already have this enhancement in one of my local branch for Cortex M7. I 've just push it on the repo: https://github.com/stm32duino/Arduino_Core_STM32/commit/a71ed8de18ba2054d21e2112c57cd1c245c103df

#if (__CORTEX_M == 0x07U) && !defined(UNUSED_ID_CACHE)
// Defined in CMSIS core_cm7.h
  SCB_EnableICache();
  SCB_EnableDCache();
#endif

STM Core (using -Os) + I/D-cache enable Loops: 1000 Iterations: 1 Duration: 2988 millisec. C Converted Double Precision Whetstones: 33.47 MIPS

So, now results are almost the same. Anyway, I don't know how @ChrisMicro had this result 202.84 MIPS

[ChrisMicro]

I stored the benchmark software here, but it was one year ago, so I don't remember exactly: https://github.com/ChrisMicro/ArduinoBenchmarkAllPlatforms/tree/master/WhetStone So simply run it on both frameworks: GENERIC and STM and make a comparison.

[fpistm]

I've used this one https://github.com/stm32duino/STM32Examples/tree/master/examples/Benchmarking/Whetstone And I've run it on both core to compare.

[fpistm]

Ok the difference is @ChrisMicro whetstone version working on float while mine on double (Single vs Double precision) Using float version this is the result for STM Core (using -Os) + I/D-cache enable: Loops: 1000, Iterations: 1, Duration: 409 ms. C Converted Single Precision Whetstones: 244.50 MIPS

So, all is understood and answered. Thanks all

[ChrisMicro]

Yes, it could probably quite inefficient to run double precision benchmarks on a single precision FPU.

[fpistm]

Right, I will provide the Single precision version.

[fpistm]

I've push the Single Precision example: https://github.com/stm32duino/STM32Examples/tree/master/examples/Benchmarking/Whetstone

Result with this version for both core:

STM Core (using -Os) + I/D-cache enable: Loops: 1000 Iterations: 1 Duration: 399 millisec. C Converted Single Precision Whetstones: 250.63 MIPS

STM32GENERIC (using -Os) Loops: 1000 Iterations: 1 Duration: 406 millisec. C Converted Single Precision Whetstones: 246.31 MIPS

[Vicky-S]

STM Core (using -Os) + I/D-cache enable: Loops: 1000 Iterations: 1 Duration: 399 millisec. C Converted Single Precision Whetstones: 250.63 MIPS

Do i need to update the core to get this result?

[fpistm]

This will be in the next release. Currently, it is available in the git repo

[Vicky-S]

If u dont mind can u help me in installing STM32 official core from git repo?? Can u share the steps to do it?

[fpistm]

https://github.com/stm32duino/wiki/wiki/Using-git-repository