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by jahboater
Wed Mar 09, 2016 7:47 pm
Forum: Troubleshooting
Topic: RPi 3 - Very poor wifi performance
Replies: 77
Views: 132409

Re: RPi 3 - Very poor wifi performance

The latest rpi-update kernel now disables power saving by default. If you have had issues, the please remove any current workarounds and try the rpi-update firmware/kernel and report if it works for you. Hi Dom, I applied the update and it works for me. I had longish and erratic ping times (say 60-...
by jahboater
Wed Mar 09, 2016 5:31 pm
Forum: Troubleshooting
Topic: Pi3 wifi dies - Solved
Replies: 15
Views: 8828

Re: Pi3 wifi dies

You could try turning off power save

Code: Select all

iwconfig wlan0 power off
by jahboater
Wed Mar 09, 2016 8:19 am
Forum: Beginners
Topic: Underclocking my pi3 to 900mhz
Replies: 12
Views: 27746

Re: Underclocking my pi3 to 900mhz

Well i kinda liked wlan and bluetooth being integrated on the board for saving space in the case and i was told the armv8 processor also works a bit more efficient at the same clockspeed than the armv7 of the pi2 so i thought for heating issues ill clock it down to the speed of the pi2 and keep the...
by jahboater
Tue Mar 08, 2016 4:27 pm
Forum: Python
Topic: Music player that manipulates frequencies
Replies: 5
Views: 1229

Re: Music player that manipulates frequencies

Disk space is so cheap now, I just use flac.
by jahboater
Tue Mar 08, 2016 3:46 pm
Forum: Beginners
Topic: Underclocking my pi3 to 900mhz
Replies: 12
Views: 27746

Re: Underclocking my pi3 to 900mhz

ok so i schould not write something with overvolt -1? im asking because overvolt is common if overclocking to certain speeds and negative overvolt too i think? or is it just that i would have to underclock it further before starting to undervolt it? When I tried "over_voltage=-1" it failed to boot ...
by jahboater
Tue Mar 08, 2016 3:34 pm
Forum: Advanced users
Topic: Winging a Pi 3 overclock
Replies: 69
Views: 23493

Re: Winging a Pi 3 overclock

Have a look at bcmstat.sh as well.
https://raw.githubusercontent.com/Milho ... bcmstat.sh
Lots of info and in colour too.
by jahboater
Tue Mar 08, 2016 9:15 am
Forum: Beginners
Topic: Underclocking my pi3 to 900mhz
Replies: 12
Views: 27746

Re: Underclocking my pi3 to 900mhz

Well i kinda liked wlan and bloetooth being integrated on the board for saving space in the case and i was told the armv8 processor also works a bit more efficient at the same clockspeed than the armv7 of the pi2 so i thought for heating issues ill clock it down to the speed of the pi2 and keep the...
by jahboater
Mon Mar 07, 2016 8:42 am
Forum: General discussion
Topic: Benchmarking a raspberrypi compared to my own PC [obsolete and locked]
Replies: 51
Views: 25643

Re: Benchmarking a raspberrypi compared to my own PC

Result for i7-3770 using 32-bit "Integer" (gcc 5.3). Found a total of 664579 primes (32-bit) real 0m1.063s user 0m1.060s sys 0m0.000s Found a total of 664579 primes (32-bit) real 0m0.975s user 0m0.972s sys 0m0.000s Found a total of 664579 primes (32-bit) real 0m0.976s user 0m0.976s sys 0m0.000s Sadl...
by jahboater
Sun Mar 06, 2016 7:10 pm
Forum: Beginners
Topic: Raspberry Pi+ Ubuntu
Replies: 4
Views: 970

Re: Raspberry Pi+ Ubuntu

jamesh wrote:Might be worth trying Raspbian instead of Ubuntu - better support here.
Yes - and ssh is enabled by default on Raspbian.
Ubuntu is a derivative of Debian.
So is Raspbian (as its name suggests) but with special optimizations for the Pi hardware, and masses of community support.
by jahboater
Sun Mar 06, 2016 11:09 am
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

The results for the prime.c program show that adding the appropriate -mcpu and -mfpu options for the Pi 2B and Pi 3B result in respectively 3.8 and 4.9 times faster run times compared to the same program running on the same hardware compiled using only -O3 optimization and the default hardware targ...
by jahboater
Sun Mar 06, 2016 10:22 am
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

If I'm building for RPi2B I've got -mcpu=cortex-a7 -mfpu=neon-vfpv4 -mfloat-abi=hard -mtls-dialect=gnu2 what options should I use to build and optimise the code for an RPI3B (without going 64 bit)? You can change the "cortex-a7" to "cortex-a53" but it wont make much difference. The fpu options rema...
by jahboater
Sun Mar 06, 2016 9:58 am
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

I think on x86 GCC is pretty good at detecting the exact processor type. Using "-march=native" produces identical code on my x86 to "-march=ivybridge" for example. On ARM it is not, and defaults to the lowest common denominator. I also found a larger variance in the code produced by different compil...
by jahboater
Sat Mar 05, 2016 6:08 pm
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

The reported i7-6700K 4.0 GHz speed of 0.6 seconds seems surprisingly fast to me. While it is a different compiler using additional -msse2 -mfpmath=sse optimization settings, it would be great if someone else with similar hardware could obtain similar timings. Alternatively, could the test could be...
by jahboater
Sat Mar 05, 2016 6:01 pm
Forum: General discussion
Topic: Benchmarking a raspberrypi compared to my own PC [obsolete and locked]
Replies: 51
Views: 25643

Re: Benchmarking a raspberrypi compared to my own PC

ARM fp registers have been 64 bit for quite a while. Like, as long as there have been fp registers. Tim, thank you for pointing this out to me. I wrongly assumed a float point double precision operations were being simulated using to single precision floating point instructions. I also verified the...
by jahboater
Sat Mar 05, 2016 10:09 am
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

So the i7 is 500% faster running this (rather simple) load. I'd expect the difference to be even larger in more taxing and memory intensive loads. Using all eight hardware threads on the i7 would of course extend that lead further. Anyway, always fun to compare, even if it's not very useful in this...
by jahboater
Fri Mar 04, 2016 7:49 pm
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

Since this is a non-parallel code, I would be surprised if running it 10 times in a row would cause the CPU to enter thermal throttling. A parallel CPU stress test that simultaneously exercises the GPU while keeping track of performance would be interesting. This Pi3 has a heatsink and (at 1200MHz ...
by jahboater
Fri Mar 04, 2016 7:06 pm
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

I wonder why the difference of 4.3 seconds on one system and 3.6 on the other. I haven't looked at the source code for this test, but do remember that it is running on linux not a RTOS. What do we get if we repeat the test 10 times on the same Pi? Its just a small C program. I did run it several ti...
by jahboater
Fri Mar 04, 2016 6:17 pm
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

4.3s for 664579 primes Well I made it 3.6 seconds for 664579 primes. Assuming no modifications were made to the source code or algorithms, the smaller value more closely represents the capabilities of the hardware. Therefore the Pi 3B appears to be 2 times faster than the 2B and only slightly slowe...
by jahboater
Fri Mar 04, 2016 5:06 pm
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

Well I made it 3.6 seconds for 664579 primes.
My pi3 is not over clocked.
Its running Jessie Lite.
by jahboater
Fri Mar 04, 2016 3:43 pm
Forum: Beginners
Topic: Just cannt seem to get an OS to run
Replies: 18
Views: 2038

Re: Just cannt seem to get an OS to run

Jahboater, I am not sure where you think I was going wrong as the instructions state that you need to format the SD card and I see that the image has the partitions all set up which can then be seen after the dd has finished. The RPi just did not want to boot r talk to the SD card. Regards Matt Its...
by jahboater
Fri Mar 04, 2016 2:03 pm
Forum: Beginners
Topic: Just cannt seem to get an OS to run
Replies: 18
Views: 2038

Re: Just cannt seem to get an OS to run

To save time in the future, you NEVER need to format the card first before installing Rasbian from a ".img" file. The image file has the partition table and the two partitions already set up. This is not a typical Linux "install" as such. It is a simple copy of a complete working system (I have neve...
by jahboater
Fri Mar 04, 2016 1:42 pm
Forum: General discussion
Topic: Pi 3 power supply & USB cable
Replies: 71
Views: 339151

Re: Pi 3 power supply & USB cable

http://thepihut.com/collections/raspber ... wer-supply
Its a great power supply 5.1v 2.5A and only £6.
It comes with a decent cable attached and the correct micro-usb plug of course.
by jahboater
Fri Mar 04, 2016 1:34 pm
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 245109

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

The LEDs (and others) seem now to hang off a GPIO expander - the WiFi/BT combo chip gobbled up so many there weren't enough left. No idea about the details yet. From what I have seen, I am led to believe that the LED's are now controlled through a Mailbox, the additional class for the virtual GPIO ...
by jahboater
Fri Mar 04, 2016 1:19 pm
Forum: General discussion
Topic: Pi3 speed compared to Pi2
Replies: 91
Views: 20086

Re: Pi3 speed compared to Pi2

On the Pi3 I found no measurable difference in performance between "-mcpu=cortex-a7" and "-mcpu=cortex-a53" options. The executable was a few bytes smaller for the a53 version.
by jahboater
Thu Mar 03, 2016 8:29 pm
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 245109

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

asandford wrote:Not a showstopper, but poweroff command leaves the green LED on.
I think there is something wrong with the on-board leds.
In "/sys/class/leds", there is only led0, there should be led1 as well which was the red power led.
How do you turn off the red led?

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