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BeagleBone Black GPIO Benchmark

Look what the mailman brought: It’s a shiny (or maybe matte?) BeagleBone Black, freshly arrived (actually it’s been over a month, but time sure flies…) from Newark element14! I’ve been doing Raspberry Pi related hacking for a while, but especially when the Pi was still fresh and new, I did from time to time consider if the grass would be greener on other side of the fence. Or blacker, in this case, as I mean BeagleBone Black.

BeagleBone was long very much more powerful than Raspberry Pi, but now that Pi2 has come out, price and specification-wise they are closer than ever. A quick personal comparison chart:

	BeagleBone Black	Raspberry Pi 2 (B)
Price	46 € (Element14)	32 € (Element14)
Processor	1GHz single-core Cortex-A8	0.9GHz quad-core Cortex-A7
Memory	512MB DDR3	1GB
Connections	USB host, USB device, micro-HDMI	4x USB, HDMI, 3.5mm Audio/analog video
GPIO	2x 46 pin headers (65 digital I/O)	40 GPIO pins (26 digital I/O)
Other	4GB integrated flash, works as USB device	camera and display interface on board

When Pi1 was out, the BeagleBone Black with the more modern Cortex-A8 chip and higher clockrate was definitely the more powerful, but now with 4-core Pi2, the tables have somewhat turned. Still, the clockrate is higher and there’s more GPIO. And speaking of GPIO, my Raspberry Pi vs. Pi2 GPIO benchmark has gotten a lot of interest, so I thought the best way to take this black beauty for a test drive would be to benchmark BeagleBone Black GPIO in a similar way.

Test setup

The test subject is the most recent revision C of BeagleBone Black. I followed the (a bit lacking in detail and readability) Getting Started guide and downloaded the latest Debian Jessie image (8.3, 2016-01-24), flashed it to card and ran apt-get update and apt-get dist-upgrade (2016-04-14).
Continue reading BeagleBone Black GPIO Benchmark

Raspberry Pi 2 vs. 1 GPIO Benchmark

It’s battle time! Some of you may have heard that Raspberry Pi 2 is out with more punch than ever. Just how much more? Well, apt-get dist-upgrade went about 5 times faster with the new Pi. With 1 GB of RAM and four cores, this will definitely be a boost for my home SSH box ergonomics over the previous version.

But what about hacking? There has been a lot of interest in getting GPIO benchmarks for the Pi 2 similar to my earlier Raspberry Pi GPIO benchmark. Well here it is! Please refer to the earlier article for source code and nice screenshots of square waves, as I’ll concentrate on the performance difference only here. You can also get the code from Github:

https://github.com/jokkebk/rpi-gpio-benchmark

Summary of results

All the Pi 1 benchmarks were ran 14th and 15th February 2015 using latest versions of the libraries as stated in my updated benchmark post. Pi 2 benchmarks were all run 25th and 26th March 2015 with the latest versions. If you get significantly different results at a later date, please let me know and I’ll update the table!

Language	Library	Pi 1	Pi 2	Change
Shell	/proc/mem access	2.8 kHz	7.0 kHz	2,5x
Shell / wiringPi	WiringPi gpio utility	40 Hz	95 Hz	2,4x
Python	RPi.GPIO	70 kHz	243 kHz	2,5x
Python	wiringpi2 bindings	28 kHz	103 kHz	3,7x
Ruby	wiringpi bindings	21 kHz	N/A	3,7x
C	Native library	22 MHz	41.7 MHz	1,9x
C	BCM2835	5.4 MHz	7.2 MHz	1,3x
C	WiringPi normal GPIO wiringPiSetup()	4.1 MHz	9.3 MHz	2,3x
C	WiringPi GPIO wiringPiSetupGpio()	4.6 MHz	9.4 MHz	2x
C	WiringPi sys wiringPiSetupSys()	120 kHz	185 kHz	1.5x
Perl	BCM2835	48 kHz	154 kHz	3.2x

Continue reading Raspberry Pi 2 vs. 1 GPIO Benchmark

Raspberry Pi GPIO Benchmark Updated!

The new Raspberry Pi model 2 is out and the Pi world seems more popular than ever. My 2012 benchmark of different RaspPi GPIO access methods has been getting a lot of hits, so I thought to revisit it, and have now updated all the benchmarks with latest versions of firmware and GPIO libraries. I’ve also upgraded my oscilloscope to PicoScope 5444B, so the scope bandwith limitations I had earlier are now gone. :)

Because the benchmark has been linked from many other sites, I’ve just updated the old post to keep links pointing to right places.

Read the updated Raspberry Pi GPIO Speed Benchmark!

Benchmarking Raspberry Pi GPIO Speed

UPDATE2: You may also want to check out my Raspberry 2 vs 1 GPIO benchmark!

UPDATED: 2015-02-15! This article has been very popular, so I’ve now updated all the benchmarks using the latest firmware and library versions. The scope has also been upgraded to a PicoScope 5444B with better resolution and bandwith than the earlier models. :)

Don’t try this at home! Shorting GND and VCC with a probe might fry your Pi and more!

Method and Summary of Results

The basic test setup was to toggle one of the GPIO pins between zero and one as fast as possible. GPIO 4 was selected due to easy access and no overlapping functionality. This is basically the “upper limit” for any signalling one can hope to achieve with the GPIO pins – real-life scenarios where processing needs to be done would need to aim for some fraction of these values. Here are the current results:

Language	Library	Tested / version	Square wave
Shell	/proc/mem access	2015-02-14	2.8 kHz
Shell / gpio utility	WiringPi gpio utility	2015-02-15 / 2.25	40 Hz
Python	RPi.GPIO	2015-02-15 / 0.5.10	70 kHz
Python	wiringpi2 bindings	2015-02-15 / latest github	28 kHz
Ruby	wiringpi bindings	2015-02-15 / latest gem (1.1.0)	21 kHz
C	Native library	2015-02-15 / latest RaspPi wiki code	22 MHz
C	BCM 2835	2015-02-15 / 1.38	5.4 MHz
C	wiringPi	2015-02-15 / 2.25	4.1 – 4.6 MHz
Perl	BCM 2835	2015-02-15 / 1.9	48 kHz

Shell script

The easiest way to manipulate the Pi GPIO pins is via console. Here’s a simple shell script to toggle the GPIO 4 as fast as possible (add sleep 1 after both to get a nice LED toggle test):

#!/bin/sh

echo "4" > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio4/direction

while true
do
	echo 1 > /sys/class/gpio/gpio4/value
	echo 0 > /sys/class/gpio/gpio4/value
done

Continue reading Benchmarking Raspberry Pi GPIO Speed