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by bitbank
Fri Apr 01, 2016 6:37 am
Forum: Beginners
Topic: Raspberry Pi 2: FFT computing capabilities
Replies: 20
Views: 3581

Re: Raspberry Pi 2: FFT computing capabilities

I would like to see your SSE code. If a 1 Ghz Cortex-A7 is beating a 3Ghz Core 2 Duo, then you're doing something very very wrong. I've been writing optimized code on Intel and ARM code for more than 16 years and properly written SSE/SSE2 code will beat NEON on the machines you're comparing. You men...
by bitbank
Thu Mar 31, 2016 9:52 am
Forum: Beginners
Topic: Raspberry Pi 2: FFT computing capabilities
Replies: 20
Views: 3581

Re: Raspberry Pi 2: FFT computing capabilities

beating even Intel's SSE SIMD I'm glad that you're experimenting with the DCT algorithm on NEON and sharing the results. A few thoughts... Intel's SSE SIMD usually takes more instructions to do the same job as NEON, but is almost universally faster due to their advanced multi-issue pipelining, out-...
by bitbank
Sun Mar 27, 2016 10:14 am
Forum: Graphics, sound and multimedia
Topic: I just open-sourced my imageinfo tool
Replies: 0
Views: 304

I just open-sourced my imageinfo tool

If you're using ImageMagick's Identify tool and don't need it's full capabilities, I've written an open-source replacement. It identifies a wide range of files, displays useful info and doesn't have any external dependencies. The code runs several orders of magnitude faster than Identify because the...
by bitbank
Fri Mar 25, 2016 11:39 am
Forum: Advanced users
Topic: Bluetooth send() from RPi locks up
Replies: 5
Views: 1828

Re: Bluetooth send() from RPi locks up

I re-tested this on the Raspberry Pi 3 and Dragonboard410c; they both work reliably without any problems. The bluetooth socket lockup only occurs on the RPI2 with an old bluetooth dongle.

I published the project as open-source (ZeeMouse) here: https://github.com/bitbank2
by bitbank
Thu Mar 24, 2016 2:33 pm
Forum: General discussion
Topic: I just 'open sourced' my ZeeMouse project
Replies: 5
Views: 2319

Re: I just 'open sourced' my ZeeMouse project

I forgot to mention that it's written in C. If there were any performance-critical functions, I would have written them in assembly language :)
by bitbank
Thu Mar 24, 2016 11:55 am
Forum: General discussion
Topic: I just 'open sourced' my ZeeMouse project
Replies: 5
Views: 2319

I just 'open sourced' my ZeeMouse project

ZeeMouse is a Linux GTK GUI program to allow bluetooth game controllers to control the mouse and/or generate key presses from button and stick movements. The name is a reference to the original version from several years ago which I wrote to communicate with the ZeeMote bluetooth game controller. Th...
by bitbank
Mon Mar 21, 2016 10:08 am
Forum: General discussion
Topic: AArch64 code execution on Raspberry Pi3.
Replies: 36
Views: 19021

Re: AArch64 code execution on Raspberry Pi3.

What I meant was the ARM compiler from ARM themselves (You have to pay for it, or used to anyway). The licence we have here doesn't cover A53 cores. You can do baremetal 64bit code already. I haven't used ARM's compiler, but I'm sure it does a better job than GCC. For my work, the compiler isn't th...
by bitbank
Sun Mar 20, 2016 3:50 pm
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 16516

Re: Pi3 speed compared to Pi2

I shared an open-source project (gcc_perf) to test the speed of RPi2/RPi3 and the Dragonboard410c. It also shows how well GCC does in ARM32 and ARM64 environments. It's on github here: https://github.com/bitbank2/gcc_perf The results are on the repo in text files if you're just curious about the spe...
by bitbank
Sat Mar 19, 2016 8:42 pm
Forum: General discussion
Topic: AArch64 code execution on Raspberry Pi3.
Replies: 36
Views: 19021

Re: AArch64 code execution on Raspberry Pi3.

I updated my performance test to run the C+SIMD part on x86 Linux. GCC for X86 in general does a better job at vectorization, but some things still didn't get optimized very well. What surprised me the most was that the integer and float version of the same function got very different treatment.
by bitbank
Fri Mar 18, 2016 3:09 pm
Forum: General discussion
Topic: AArch64 code execution on Raspberry Pi3.
Replies: 36
Views: 19021

Re: AArch64 code execution on Raspberry Pi3.

3) I don't want to diminish the hard work of the people behind GCC, but the ARM version has been hit or miss for quite some time. The version distributed with Debian Jessie is GCC 4.9. It has come a long way, but it still stumbles on auto-vectorization and generating decent code from SIMD intrinsic...
by bitbank
Fri Mar 18, 2016 2:42 pm
Forum: General discussion
Topic: AArch64 code execution on Raspberry Pi3.
Replies: 36
Views: 19021

Re: AArch64 code execution on Raspberry Pi3.

As promised, I created an open source tool to test the performance of code execution (as well as GCC's output) on 32-bit and 64-bit ARM systems. If you just want to see the results and can't/don't want to build it, they're included in the git repo as text files. The project is hosted here: https://g...
by bitbank
Wed Mar 16, 2016 10:27 am
Forum: General discussion
Topic: AArch64 code execution on Raspberry Pi3.
Replies: 36
Views: 19021

Re: AArch64 code execution on Raspberry Pi3.

bitbank, In what way is GCC in a sad state for ARM? My assumption, without much research, is that when I switch from a 32 bit to a 64 bit OS on my desktop nothing much happens. I don't magically get a faster instruction execution rate. I don't magically get a wider bus to memory. My caches are the ...
by bitbank
Wed Mar 16, 2016 6:31 am
Forum: General discussion
Topic: AArch64 code execution on Raspberry Pi3.
Replies: 36
Views: 19021

Re: AArch64 code execution on Raspberry Pi3.

madscientist42, ...offers in many of the cases a decent to massive jump in speed. Do you have any evidence to back that up ? For example moving from a 32 bit Debian installation to a 64 bit on my four core Intel PC makes no appreciable difference in performance. I could imagine that a 64 bit build ...
by bitbank
Mon Mar 14, 2016 7:41 am
Forum: C/C++
Topic: OpenCV+Raspberry Pi Camera Module
Replies: 3
Views: 1131

Re: OpenCV+Raspberry Pi Camera Module

Can you elaborate on what "un-distort" the data means? 500ms is a long time (for a computer). Are you using all 4 cores or just 1?
by bitbank
Mon Mar 14, 2016 6:53 am
Forum: General discussion
Topic: AArch64 code execution on Raspberry Pi3.
Replies: 36
Views: 19021

Re: AArch64 code execution on Raspberry Pi3.

The only place you would have an advantage from 64 bit code, would be in video procesesing, but only if you had 4 or more gigabytes of RAM, so best option would be to utilise the NEON extension that is available and as far as I can tell under utilised. Please stop repeating this incorrect informati...
by bitbank
Wed Mar 02, 2016 6:46 am
Forum: General discussion
Topic: AArch64 code execution on Raspberry Pi3.
Replies: 36
Views: 19021

Re: AArch64 code execution on Raspberry Pi3.

I too would like to see Aarch64 running on the Pi3, but after reading what the Pi organization said, the chances seem slim. One reasonably priced alternative is the Dragonboard 410c from Arrow Electronics. I got one for $75 and it runs Linaro's 64-bit Linux. It's not quite as functional as advertise...
by bitbank
Mon Feb 29, 2016 6:24 pm
Forum: Raspbian
Topic: How do you set up Bluetooth on Pi 3
Replies: 32
Views: 10101

Re: How do you set up Bluetooth on Pi 3

I used to be able to do reliable socket connections to bluetooth game controllers with bluez, but the last version I tried on my Pi2 doesn't work at all (nor does it work properly on my Aarch64 Dragonboard 410). I certainly hope the built-in bluetooth properly supports RFCOMM sockets. I'll find out ...
by bitbank
Mon Feb 29, 2016 2:04 pm
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 206944

Re: The Raspberry Pi 3 Model B Q&A thread

1g of ram, 64bit cpu, what is point? more ram eating? ARMv8 brings a bunch of improvements including double the number of general purpose registers, double-wide registers, double the number of NEON registers, and an improved instruction set (including integer divide). The extra registers alone usua...
by bitbank
Mon Nov 30, 2015 3:32 pm
Forum: Advanced users
Topic: Bluetooth send() from RPi locks up
Replies: 5
Views: 1828

Re: Bluetooth send() from RPi locks up

I realize this post is rather old, but did you ever find a solution? I'm trying to do some rfcomm communication with game controllers in C and I'm seeing a similar problem (besides pairing issues).

Thanks,
Larry B.
by bitbank
Mon Nov 09, 2015 6:34 am
Forum: Graphics, sound and multimedia
Topic: New imaging utilities
Replies: 4
Views: 735

Re: New imaging utilities

I can only open files singly That's the current design of FIV - one file at a time (can be multi-page). On OSX I'm designing a new version which allows opening/navigating a directory or group of files. The main advantage of my viewer is that it can open huge bitonal images on slow systems with litt...
by bitbank
Sun Nov 08, 2015 5:48 pm
Forum: Graphics, sound and multimedia
Topic: New imaging utilities
Replies: 4
Views: 735

Re: New imaging utilities

Thanks for your comments. Feedback is hard to come by, especially on iOS. I've been trying to make a binary which can run on both RPi 1 and 2, but GCC is making it difficult. I use NEON intrinsics in my main C module and if I enable neon code, then GCC uses armv7 instructions in unexpected places an...
by bitbank
Sat Nov 07, 2015 8:28 am
Forum: Graphics, sound and multimedia
Topic: DCP package creation
Replies: 1
Views: 392

Re: DCP package creation

What format are the source TIFF images? Is the time spent decoding, encoding or both? I haven't written a J2K codec, but I have written a very fast set of codecs for TIFF. Maybe I can speed it up. Please share a sample frame and I'll take a look (use something like dropbox?).

Larry B.
by bitbank
Sat Nov 07, 2015 8:10 am
Forum: Graphics, sound and multimedia
Topic: New imaging utilities
Replies: 4
Views: 735

New imaging utilities

Hello RPi community. I'm relatively new to the Raspberry Pi, but I'm already hooked. I've been porting a bunch of my applications to run on the RPi and I decided to open-source a couple of useful little utility apps: (https://github.com/bitbank2). I also ported my image viewer (Fast Image Viewer) to...

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