Questions tagged [cpu]

Central Processing Unit, or processor for short.

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57
votes
8answers
75k views

Will Raspbian move to 64-bit?

In this page, the official RPi3 announcement states: You’ll need a recent NOOBS or Raspbian image from our downloads page. At launch, we are using the same 32-bit Raspbian userland that we use on ...
15
votes
4answers
53k views

How can I lower the usage of CPU for this Python program?

I will be having a Python run 24/7 in a while loop, here is an example of the sort of program: while True: print ("me again...") But when I run it, my CPU goes to 100%! But I don't want that ...
12
votes
1answer
4k views

Can a Pi be used as an OpenCL CPU device?

Can I use a Pi (or, for that matter, Beagle Bone or Arduino) as an OpenCL CPU device? I understand there isn't much of a GPGPU thing on a Pi, but couldn't I link a bunch together under an OpenCL ...
11
votes
12answers
30k views

Can I use all 4 cores of the Raspberry Pi's CPU?

I was wondering if there is a simple way to "turn on" all 100% of the CPU so that I can run processes faster (such as python calculations). 1) Is this possible? 2) Is there an easy way to revert ...
6
votes
2answers
4k views

Why does the Raspberry Pi's GPU control the first stages of the boot process?

According to the answers to this question and other sources, the GPU of the Raspberry Pi's BCM2835 SoC is responsible for the first stages of the boot process, including enabling the ARM CPU. Until ...
6
votes
1answer
2k views

Lxpanel using 100% CPU (1 core)

On my Raspbian 2018-11-13 installation with all updates (sudo apt-get update and sudo apt-get upgrade), I see the CPU graph in the task bar (top right corner) at constant 25%. I opened a terminal and ...
6
votes
1answer
15k views

End Kernel panic - not syncing: Attempted to kill init

I have a problem when starting my Raspberry Pi (Rasberry Pi 3 Model B). Everything worked fine. After the last reboot I've got this error. Any help would be appreciated.
5
votes
2answers
3k views

Can Compute Modules provide clustering and high availability?

I am very interested in Compute Modules, but have a few concerns: The main press release (linked above) for Compute Modules states that these systems are "primarily designed for those who are going ...
5
votes
1answer
181 views

Crosscompiling: exact archictecture for all models

I would like to crosscompile some piece of C++ software in a way that I can run on every Raspberry Pi. I am confused about the parameter -march. I've found a great deal of resources recommending to ...
5
votes
3answers
8k views

New PI 2 B+ unusably slow, CPU and RAM not being used?

Just setup a new R Pi 2B+, using raspbian on a 16gb sd card, ethernet, USB mouse/keyboard and HDMI out. Finding it extremely slow - the UI is reasonably responsive however installing monodevelop took ...
5
votes
1answer
1k views

How to achieve gpu_mem=8?

I see some people claiming (see links) they have a memory splitting of gpu_mem=8, but I always thought 16/496 is the minimum split? Here is an answer on this very page: https://raspberrypi....
5
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1answer
1k views

rpi 2: Unable to change irq affinity

I am trying to optimise getting GPIO interrupts into userspace. On the single core rpi 1 I couldn't get rid of quite some timing jitter, which makes sense as there's a lot of stuff going on on the cpu....
4
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1answer
4k views

How does a Raspberry Pi deal with high temperature?

Is there a overheating protection circuit integrated into the Raspberry Pi like in desktop processors from Intel or AMD? When I did research about this question I just found vendor specification about ...
4
votes
2answers
5k views

Virtualization on Pi 3 Raspbian

The new Pi 3 was announced this morning. It's the first Pi to ship with a 64-bit processor, the ARM Cortex A53. The product page for that chip suggests that it's capable of hardware virtualization. ...
4
votes
1answer
104 views

How is CPU in Raspberry Pi 4 +36% faster than for Raspberry Pi 3?

CPU benchmarks show that the Raspberry Pi 4 outperforms Raspberry Pi 3 by +36% https://www.geeks3d.com/20190930/raspberry-pi-4-vs-raspberry-pi-3-cpu-and-gpu-benchmarks/ How is this possible given the ...
4
votes
2answers
231 views

Raspberry Pi sensor error with high CPU

I have a passive infrared sensor attached to a Raspberry Pi. Namely this model which has digital output in addition to the analog one so it can be attached directly to Raspberry Pi. The data pin is ...
4
votes
1answer
5k views

Uptime shows high load, but cpu is mostly idle

Since my last reboot May 1st, uptime shows an average CPU usage of ~4, but top and iotop are ok. Does anyone has an idea what else to check? pi@raspberrypi ~ $ uptime 08:57:14 up 14 min, 1 user, ...
3
votes
6answers
22k views

How to directly get CPU temp in Python?

Goal is to switch an exhaust fan at an outside data-logging station at a solar power station. The data-collection program is written in Python under Raspbian. For reading CPU temp at a command line, ...
3
votes
3answers
849 views

Is my code too intensive on the cpu?

I am currently building a remote controlled car with the RPi model A+. I am using pygame to run a continuous loop to check the states of the desired keys on the keyboard(w,a,s,d) and based on that run ...
3
votes
1answer
359 views

Can the Raspberry Pi 4 better distribute Python scripts to all four cores?

This relates to previous questions regarding the GIL (Global Interpreter Lock) for Python on the Raspberry Pi. My question has to do with the new processor on the Pi 4 - does it still have the same ...
3
votes
1answer
106 views

Raspberry Pi's reaction to 7.2 Volts applied to a GPIO pin?

I was using a Raspberry Pi 3 model B in a project. The Pi was connecting to a web socket and receiving data from the user on a PC or whatever device connected to the same socket. It was fine at first....
3
votes
3answers
3k views

When does the OS kill an application?

I have an application which polls a bunch of servers every few minutes. To do this, it spawns one thread per server to poll (15 servers) and writes back the data to an object, however sometimes the ...
3
votes
1answer
2k views

Using GPU to decode QRCODE

I'm using a raspberry pi compute module and my question is : Can we use the GPU to decode QRCODE ? I am using my own function inspired by the one from QRTOOLS and by doing so the timing is divided by ...
3
votes
3answers
4k views

CPU Performance Graph

Is it possible to get a larger view of the CPU graph shown in the bottom right of my Raspbian desktop? Just to show the graph I am talking about:
3
votes
1answer
131 views

How to get curent cpu mhz on a raspberry pi with python?

I need a sample program that will put the current CPU MHz in a variable with python. I prefer a short compact program. Thanks in advance.
3
votes
2answers
144 views

Raspbian Lite uses less cpu?

Does Raspbian lite version use less cpu / memory than the full Raspbian. I know the lite uses less storage for sure but not sure on the cpu memory. I am running some time critical code I am thinking ...
3
votes
2answers
718 views

Cooling down the Raspberry Pi 3 in a Vacuum

I'm working on a small little project involving the Raspberry Pi 3 and the LSM9DS1 Breakout board from Adafruit. We plan to place the Pi and the sensor board in a high radiation environment (but ...
3
votes
2answers
141 views

CPU speed changes by a multiply of 2 for short durations

I'm using a raspberry pi and I need really fast performance from my CPU for a certain process. To achieve that, I added isolcpus=3 to my kernel boot parameters, to isolate the core for this process ...
3
votes
1answer
2k views

Temperature differences between CPU & GPU

So recently I was interested in CPU and GPU temperatures and did some work displaying the temperatures in real time on a page and also recording the temperatures on a graph using rrdtool (which is ...
3
votes
1answer
2k views

Raspberry Pi clock speed won't increase

I overclocked the raspberry pi to 900mhz with raspi-config, however, when I use "cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq" to check the speed, I get 600,000 (600 Mhz). This is causing ...
3
votes
1answer
904 views

Memory split - How much is the GPU responsible for?

I am using my Pi2 to run some Python scripts that are heavily use the CSI camera (being pulled with the picamera module), being processed with OpenCV, and draw a GUI to screen (using the PyGame module)...
3
votes
0answers
180 views

Ubuntu Mate pernament CPU governor state?

I'm changing Rpi3 with Ubuntu Mate governor on user login to 'performance' but it seems like the kernel is changing the state back to original value after some time (ALSO THE 7" LCD SCREEN BRIGHTNESS)....
2
votes
1answer
2k views

How to decrease CPU usage of conky

those of you who dont know what conky is, its a GUI for desktop raspbian that shows you loads of information about your pi at that moment, for example temperature, CPU usage, ip address of the pi, ...
2
votes
2answers
20k views

Raspberry PI 3 as NVR

I'm planning to do a NVR with a Raspberry Pi 3. I want to record video from 8 IP cameras at 640x480@24fps with motion detection implemented in the Raspberry Pi (using motion or OpenCV probably) so the ...
2
votes
3answers
1k views

How can i discover the current CPU load?

I would like to use the percentage of CPU load in a program to discover wether or not it has an affect on some other sensors but i need to be able to get that number as an integer in python. I looked ...
2
votes
1answer
4k views

Monitor CPU voltage and overclock

Is there a way to monitor the current CPU core voltage and overclock, similarly to CPU-Z but for the raspberry pi? This is so I can check that nothing is limiting the overvolt or overclock.
2
votes
1answer
5k views

Change Temperature Monitor to display in Fahrenheit [closed]

Can I change the temperature monitor on LXPanel on Raspbian in the GUI to display in Fahrenheit? If so how do I change it?
2
votes
3answers
757 views

Does Pi Zero Have built-in-audio component?

I am looking to buy a Raspberry Pi Zero for my retro gaming project. I am asking wherher the Raspberry Pi Zero has any built-in internal audio speaker in the chip itself or not? If there isn't, is ...
2
votes
1answer
458 views

Bare metal: Why does the CPU automatically read instructions from the SD card?

I'm learning bare metal programming on the RPi. My main experience is from using 8-bit PIC microcontrollers. Reading from SD cards is comparatively high level. How does the CPU achieve this? Does it ...
2
votes
2answers
1k views

What is the most optimum memory split for streaming pi's as security monitors which you will only ssh into?

I have a few model A's and model B's. I've also read about a few options that allow you to configure an arbitrary split apart from the 16, 32, 64, 128 (and 256 for the B). Any insight would be ...
2
votes
1answer
539 views

RPi threading too slow

So I have rpi wheeled robot, with wheel encoders and I want to always keep the track of the encoders and to be able to access the value when ever I need it. Basically, I created a thread, which ...
2
votes
2answers
662 views

Why does Raspberry PI use GPU for loading bootloaders and configuration

There is a great explanation of the boot process - What is the boot sequence? But I can't understand why GPU is responsible for doing all that work. Could someone explain this decision? I can't ...
2
votes
1answer
3k views

Very high cpu load, but usage is low

I have been seeing a very high cpu usage on my Raspbery Pi: load average: 97.69, 97.60, 97.21 However, I have been closely monitoring htop for a while and cpu usage is around 30-40%. Looks like the ...
2
votes
1answer
519 views

Multiple instances of /usr/sbin/ifplugd and high CPU usage

why do i have multiple instances of /usr/sbin/ifplugd running, is there a problem Also my CPU seem to be running Maxed PPP0 is the 3g card. and currently it is connected 07:56:38 up 7:57, 1 user, ...
2
votes
2answers
1k views

Is Raspberry Pi powerful enough for a VDR with a USB HDD and USB DVB-C stick?

I'm planning to do a personal video recorder using Raspberry Pi that can take potential HDTV movies receiced from a USB DVB-C stick and record it to a USB hard disk drive. The PI should run an SSH ...
2
votes
0answers
35 views

Tuning watchdog cpu usage

I've enabled the watchdog module # /etc/modules i2c-dev bcm2835_wdt And installed and activated the watchdog daemon with the following configuration: # /etc/watchdog.conf realtime = yes priority =...
2
votes
0answers
40 views

Load CPU at a specific % with stress-ng

I'm trying to achieve a 50% CPU load on my Pi to run thermal tests on it since that's what I expect the CPU usage to be with the real application. So far I've been playing around with stress-ng and ...
2
votes
0answers
1k views

Safest highest operating temperature of a Raspberry Pi 3 Model B

What is the safest highest operating temperature of a Raspberry Pi 3 Model B? I was able to get my temperature up to 77'C by running: fulload() { dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/...
1
vote
1answer
7k views

Can I watch movies with the Rasberry Pi Zero?

I want to make a DIY home-theater system with the Raspberry Zero. My question is will the processor and RAM be enough to play a movie with no problems. (I am planning to use an HDMI cable and an ...
1
vote
2answers
252 views

Controlling fan of the LABISTS Raspberry Pi4

I'm a new Raspberry Pi 4 user. I have bought the Labists Kit which includes 3 heatsinks and a fan. As far as I understand the fan is connected directly two the GPIO pins (see for example this video ...