Raspberry Pi

[xilman]

A thread to collect together all number crunching on Raspberry Pi computers.

[ET_]

Originally Posted by xilman

My Raspberry Pi-3 arrived today. It's a kit which includes PSU, NOOBS and a Lego™-compatible case.

I'm ordering a new one (my previous went to a High School experiment related with heat probes). As I plan to use it also for math computing, I'd like to know your first impressions about it. I.E. does it work with GMP extensions and GMP-ECM?

Luigi

[xilman]

Originally Posted by ET_

I'm ordering a new one (my previous went to a High School experiment related with heat probes). As I plan to use it also for math computing, I'd like to know your first impressions about it. I.E. does it work with GMP extensions and GMP-ECM?

Luigi

I'll let you know. Not yet powered it, let alone tried it out.

Running a 64-bit OS is likely to be challenging, but that's also likely to be required in order to get decent arithmetic perfomance. I've very little doubt that 32-bit Debian will just work.

FWIW, my Parallella cluster of credit-card sized computers built around a 32-bit ARM core is running GMP-ECM very nicely. It's just another Linux box which runs essentially everything written in C. For instance, the Algol 68 Genie compiler/interpreter works perfectly.

[henryzz]

The raspberry pi 2 ran fine with gmp-ecm. The main issues I had with it were its speed was 1/20th of a Q6600 core and it had 1 GB of memory to share between 4 cores.
You should get a bit more speed on the pi 3 but I believe it still only has 1gb of memory.

[Mark Rose]

Originally Posted by xilman

FWIW, my Parallella cluster of credit-card sized computers built around a 32-bit ARM core is running GMP-ECM very nicely. It's just another Linux box which runs essentially everything written in C. For instance, the Algol 68 Genie compiler/interpreter works perfectly.

What was the solution to the ethernet problem?

[ET_]

Originally Posted by xilman

Running a 64-bit OS is likely to be challenging, but that's also likely to be required in order to get decent arithmetic perfomance. I've very little doubt that 32-bit Debian will just work.

Pi3 comes with a full-fledged 64-bit OS and 4 1.2 GHz cores, so I'm curios about its performance :-)

[xilman]

Originally Posted by ET_

Pi3 comes with a full-fledged 64-bit OS and 4 1.2 GHz cores, so I'm curios about its performance :-)

Interesting. That's not what I read elsewhere. For instance https://wiki.gentoo.org/wiki/Raspber...el_Compilation has

The official Raspberry Pi Foundation kernels are built 32 bit, which is appropriate for Raspberry Pi 1, 2 and 3 (running in 32 bit mode; recommended). This guide does not cover building a 64 bit kernel for the Raspberry Pi 3 (issues / unstable / not recommended).

and https://wiki.gentoo.org/wiki/Raspberry_Pi has

Raspberry Pi 3 B is based on BCM2837 SoC. According to #gentoo-arm, although the ARMv8 CPU in the Raspberry Pi 3 B is 64-bit, almost everything else is 32-bit, and therefore only 32-bit kernels are supplied from upstream for the machine.[1] To boot a 64-bit kernel, it is necessary to add the arm_control=0x200 parameters to the boot loader.[2] This is to enable 64-bit mode for the processor. The disable_commandline_tags=1 kernel boot argument is also needed, otherwise "the boot loader will otherwise overwrite the code (without -O2) at 0x100 with ATAGS[3]. Therefore, for the Raspberry Pi 3 B, those who want to build a 32-bit kernel, simply walk through the Raspberry Pi 2 options listed below. Those who want to try to build a 64-bit kernel will need the mainline Linux kernel. Be aware there are very few people who are able to provide assistance for 64-bit attempts. Proceeding down the 64-bit path may enter a world of pain.[4] Many things (such as Firefox[5]) may not work at all. Other things have issues but function (wifi)[6][7]. Be sure to remember to add the boot arguments!

I'm largely brainless right now because of the heavy cold mentioned in the companion Unhappy Me thread so I've not yet tried to get the Pi working.

[ET_]

Originally Posted by xilman

Interesting. That's not what I read elsewhere. For instance https://wiki.gentoo.org/wiki/Raspber...el_Compilation has
and https://wiki.gentoo.org/wiki/Raspberry_Pi has

I'm largely brainless right now because of the heavy cold mentioned in the companion Unhappy Me thread so I've not yet tried to get the Pi working.

My bad 64-bit capable CPU is not the same as 64-bit OS. There has been a branch of NOOBS, Fedora and Arch at 64-bit but it seems too heavy to maintain to be openly delivered. Only computer mathematicians would love such distro, and we do not count enough users to ask for a new kernel.

[xilman]

Originally Posted by ET_

My bad 64-bit capable CPU is not the same as 64-bit OS. There has been a branch of NOOBS, Fedora and Arch at 64-bit but it seems too heavy to maintain to be openly delivered. Only computer mathematicians would love such distro, and we do not count enough users to ask for a new kernel.

I plan to go the Gentoo route. What little I've read suggests that a system suitable for number crunching may be buildable even if all the bells and whistles that people expect these days are flaky.

There's an ulterior motive for wanting a 64-bit compute-optimized system. I'm giving very serious thought to building a baby supercomputer and, ATM, the Pi-3 appears to be the ideal machine for prototyping from a cost/benefit viewpoint. Perhaps people here may also be interested in this idea if it can be made to work.

[Mark Rose]

Depending on your application, you may or may not find the Pi's slow Ethernet to be a bottleneck. There are other small boards that have gigabit on board. Something to consider.

[xilman]

Originally Posted by Mark Rose

Depending on your application, you may or may not find the Pi's slow Ethernet to be a bottleneck. There are other small boards that have gigabit on board. Something to consider.

Thanks. That issue has already been noted but, for prototyping, I'm not too concerned because things can only get better if it works at all. Some other small boards are also better supported by 64-bit operating systems right now. Presently I want to optimize for simplicity of construction

Longer term I'd prefer not to use processing elements with all the extraneous gubbins (HDMI, USB, ethernet, ...) that stand-alone systems require. All the interfaces with the outside world ought to be (IMAO, anyway) the responsibility of a front-end processor.