Questions tagged [cpu]

Central Processing Unit, or processor for short.

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what is the relationship between worst case execution time (WCET) and cpu utilization of a raspberry pi zero

Assuming the task execution in case of single core processor be sequential, how can we possible relate the WCET of any program to CPU utilization of task and/or core frequency at which the task is ...
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MPEG-2/VC-1 Software Transcode vs Hard+Soft Decode+Encode

Is it better to directly transcode MPEG-2 (or VC-1) video into a different format (let's say h.264 as an example target) with the CPU, or is it faster to use hardware decoding (license purchase ...
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Constant CPU speed?

I'd like to run my Raspberry Pi (3b+) ARM Cortex A53 processor on a constant CPU speed, can be the lowest one, doesn't matter, as long as it does not change. I need this in order to profile some code, ...
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Design of Pico hardware divider

I recently found out that Pico has "8-cycle signed/unsigned divide/modulo circuit, per core" [1]. To my untrained embedded eye this seems very fast, does anyone know how they did it? What ...
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Raspberry Pi is constantly CPU throttling

My Raspberry Pi 4, with heatsinks and 5v fan is idling at above 85 degrees Celsius constantly! Once I was simply updating via apt-get while doing other things and it ejected the SD Card as to try to ...
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Error while Starting Raspbian

Enviroment: Device: Rasberry Pi 2 OS: Raspbian Last sign of life: 8.March 2021 Problem Since 8th of march I've got no message of my raspberry pi, so I get them and try to boot with a connected monitor....
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Can RPi control CPU temperature by itself?

i am newbie at Raspberry so maybe this question is stupid. Can RPi control CPU temperature by itself at desired point, for example 70°C? I started the RPi and tested the internet and played a movie ...
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Pi kills all the process itself

I'm using a Pi to command an home-made robot. For that I run several python scripts (and one programme in C++), they consume many CPU. I want to let the robot working for several days in a row. But ...
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Differences between B0 and C0 steppings of the BCM2711

I just acquired a Raspberry Pi 4 Model B with 4GB RAM. The processor stepping (revision) is B0 (the heat spreader says 2711ZPKFSB06B0T). It seems to be stable at 2.0 GHz with over_voltage=6; it'll ...
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Can one core of the Pi 4 run multiple hardware threads simultaneously?

According to the Raspberry Pi 4 Model B specs the SoC used is BCM2711. The BCM2711 uses an ARM Cortex-A72 core. Does this have simultaneous multi-threading (SMT), like Intel cores with hyperthreading?...
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CPU side channel mitigations on Pi 4 running Ubuntu 20.04?

I want to run a jumphost on Ubuntu 20.04 64 bit and Pi 4, as secure as possible. If I check lscpu of the vanilla install after running a dist-upgrade, I see this: Architecture: ...
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sudo apt-get upgrade is extremely slow

I run a new installation of Minimal image based on Debian Buster on Raspberry Pi 3B. sudo apt-get update gone as usuall - 1-2 minutes. However, sudo apt-get upgrade is running already 1:30 or so. And ...
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Alpine Linux architecture for Raspberry Pi 4 Model B

I need to install a 64-bit operating system for my Raspberry Pi 4 Model B, in order to install the latest version of MongoDB. I am wondering about which architecture I should use: ARMhf AArch64 ...
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Plotting CPU and Ram utilization

I want to plot the CPU and memory utilisation of an Apache server hosted in Raspberry Pi 3B+ with Raspbian Stretch in it. For that I have followed the procedure mentioned here. The instructions work ...
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Are the Rpi CPUs fabbed specifically for Raspberry Pi Foundation, or are they "off the shelf" components?

I'm curious if these are identical parts to those found in other electronic devices, or if they are fabbed specifically for the Rpi. Most interested in the latest 3 and 4s, but the history of it would ...
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Usability of a Pi 4 as a linux-based MIDI synthesizer/sampler

I'm currently using an old Core 2 Duo 1.8GHz laptop, running Lubuntu 18.04, as a synthesizer (technically, sampler) for a USB MIDI controller. It's not great—the processor seems to be too slow to ...
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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 ...
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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 ...
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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 =...
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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 ...
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How to overclock RPi 3 on Windows 10 ARM

I have an RPi3B running Windows 10 ARM (not scrappy IoT). I used WOA Deployer RPi to burn the image into SD card. I can boot into desktop, but the system is slow & laggy. When I looked up Task ...
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(Pi 3B) CPU Usage turn low while using video record and servo

I am doing a project is using Robot arm to classify package has QR code. Webcam starts streaming and if it scans correct those QR which I set in Python code, the Robot arm picks and places it to other ...
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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.
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Libreoffice using 25% total cpu, 100% one core

When Libreoffice is left open with a document in it, after a while Libreoffice begins using 25% of the total cpu usage. The usage doesn't stop, until: 1. I close Libreoffice 2. I press Ctrl+S even ...
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Can one run a Raspbery Pi Zero W at load continuously?

I want to use a RPi Zero W to drive a display. This will be putting the CPU on-load pretty much 24/7. Can it handle having load near-continuously? I do have a small metal heat sink on the CPU. I ...
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Why don't I see a CPU usage monitor in menu bar on my raspberry Pi 4? And how can I get one?

I cannot seem to find anyone asking about this or talking about this... I'm very new to computers and don't know much at all so any help would greatly be appreciated. So I have a raspberry pi 3b+ ...
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3 votes
2 answers
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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 ...
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What is the hottest part, under light load?

For a hobbyist weather station project I am going to use a Raspberry Pi and a Si7021 temperature/humidity sensor. If possible, I want to use one of the available casings, and enclose my Pi and the ...
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Tool to monitor pi performance/resources via website?

Is there a tool for the raspery pi to monitor cpu, ram, storage, resources ... sys health etc. via a web gui?
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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 ...
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Raspberry + Fedora, wrong CPU load average

For some reason, my "top" command is showing wrong cpu load average. Like 100% cpu usage everytime, but, in fact, the cpu is 100% idle. It's a Raspberry 3, running Fedora 28. CPU temperature is below ...
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CPU/RAM monitoring of one process

I know close questions have been asked, but I did not find any answer to this. I would like to monitor CPU and RAM of a process I launch, which is executed through several threads. I would like the ...
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cpufreq on arch arm aarch64 on a rpi3b+?

The distro is by and large running ok, except that apparently it is blasting at full speed (though hopefully not overclocking the cores). This eventually results in overheating my pi, which makes it ...
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Raspberry Pi 2 power consumption incorrectly

Before, i'd a problem about changing governor for my Pi (cpu always stays at 600Mhz in every mode), after doing some tweaking, i'd already make it up to 900Mhz. However, now i'm using a power-meter to ...
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"Performance" gorvernor doesn't change cpu frequency

When i tried to change the default governor of my Raspberry Pi 2 (currently at Powersave mode) to Performance mode which is expected to push my Pi's CPU freq up to its maximum number (900Mhz) by using ...
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11 votes
2 answers
6k 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 ...
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Pi Zero freezes with using camera recording / motion detect programs

I am having problems with a wildlife cam project I am working on. setup: Pi Zero W Stretch 2018-11-13 Pikrellcam with settings: 1024x768 12 fps 3,5 Mbitrate However, the pi frequently freezes. I ...
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How do I increase the RPi 3 minimum clock speed without using force_turbo?

So I don't want to change my max clock speed, but I want to slightly increase the minimum clock speed at light load from 600MHz to 800MHz. However, if I set these options in my /boot/config.txt/ and ...
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7 votes
1 answer
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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 ...
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2 answers
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CPU frequency scaling on RPi3+

This is a bit of a follow up to Why is my Pi running at 700MHz all the time? and Overclocking - CPU Frequency Measurement Accuracy: vcgencmd vs cpuinfo_cur_freq I have a Raspberry Pi B3+ (at least ...
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What causes this (strange?) CPU usage on Raspberry Pi 3?

I am running two python scripts from two different terminals like so: python3 one.py and python3 two.py one.py Waits for an input on GPIO 27, and then starts counting in seconds how long the ...
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Simple socket server taking up 75% cpu

I've made a socket server to listen for data to play a sound for a length of time. All is working fine, except I see that cpu runs constantly at 75%, and after some time I get an overheat warning. I'...
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How to increase CPU cache on Raspberry Pi?

I'm mining some Monero on my raspberry pi (Of course only for educational purposes). In order to increase my hashrate I'd like to increase my CPU cache. I already searched SE but haven't found a ...
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12 votes
7 answers
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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, ...
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Increase CPU for raspberry pi 3b+

I am running a Bitcoin Full Node on Raspberry pi 3b+. Blockchain sync is dead slow because of less CPU. Is there a way to add additional CPU to a pi board. or connecting additional pi to the same Hard ...
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3 votes
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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....
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2 votes
1 answer
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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 ...
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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 ...
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Any way to kill an application on high temperature?

I have a Raspberry Pi 3 and I'm thinking of running a process 7/24, but it sometimes uses CPU too much, and from my last 2 questions, I understood that Raspberry Pi 3 cannot power itself off on high ...
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3 votes
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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 ...
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