ejolson
Posts: 10214
Joined: Tue Mar 18, 2014 11:47 am

Re: RPi4 - Power Savings

Sun Jul 05, 2020 2:31 am

AkulaMD wrote:
Sun Jul 05, 2020 2:04 am
Endgame wrote:
Mon Jun 29, 2020 6:15 pm
Hello all,

This thread is a little old, but it’s exactly what I was looking for. If I should start a new thread, let me know.

That said, has any additional progress been made on shaving power off the pi 4?

My use case is slightly different, as I’m not running off of battery or idle, but currently running 8 pi 4s headless with raspbian lite for distributed computing (Boinc, open pandemics and Rosetta@Home). Currently, as displayed on my APC ups, I’m averaging 4.5 watts per pi at 100% cpu, and I would really like to shave that down even further. Currently, I’ve disabled / tweaked the following:

Over_voltage -2 (setting it lower has no effect)

#Disable Wifi
echo "dtoverlay=disable-wifi" | sudo tee -a /boot/config.txt

#Disable Bluetooth and bluetooth services
sudo systemctl disable hciuart
echo "dtoverlay=disable-bt" | sudo tee -a /boot/config.txt


#Disable HDMI:
sudo tvservice --off

#Turn off Power LED:
echo 0 | sudo tee /sys/class/leds/led1/brightness

#install utility to control usb power
sudo apt-get install uhubctl

#Turn off usb (though this has no measurable effect)
sudo uhubctl -l 2 -a 0

Per this thread, it looks like I could also:
Turn off Ethernet LEDs
Turn off PI4 DRM VC4 V3D driver
disable onboard audio (Minimal to no expected change?)

Is there anything else I should be looking at? Is there a better way to disable usb to save more power?

Thanks!
Hi, do i need to put in all those commands (for Bluetooth and WiFi) in config.txt. If yes, do i just copy & paste it there? Sorry for the noob question.

Wonder if there is a way to turn off the GPIO and if there is, is there any power saving from turning it off.

Thank you in advance.
They go in a shell script that would be executed after the Pi is finished booting.

User avatar
AkulaMD
Posts: 236
Joined: Fri Jun 19, 2020 6:51 am

Re: RPi4 - Power Savings

Sun Jul 05, 2020 5:50 am

ejolson wrote:
Sun Jul 05, 2020 2:31 am
AkulaMD wrote:
Sun Jul 05, 2020 2:04 am
Endgame wrote:
Mon Jun 29, 2020 6:15 pm
Hello all,

This thread is a little old, but it’s exactly what I was looking for. If I should start a new thread, let me know.

That said, has any additional progress been made on shaving power off the pi 4?

My use case is slightly different, as I’m not running off of battery or idle, but currently running 8 pi 4s headless with raspbian lite for distributed computing (Boinc, open pandemics and Rosetta@Home). Currently, as displayed on my APC ups, I’m averaging 4.5 watts per pi at 100% cpu, and I would really like to shave that down even further. Currently, I’ve disabled / tweaked the following:

Over_voltage -2 (setting it lower has no effect)

#Disable Wifi
echo "dtoverlay=disable-wifi" | sudo tee -a /boot/config.txt

#Disable Bluetooth and bluetooth services
sudo systemctl disable hciuart
echo "dtoverlay=disable-bt" | sudo tee -a /boot/config.txt


#Disable HDMI:
sudo tvservice --off

#Turn off Power LED:
echo 0 | sudo tee /sys/class/leds/led1/brightness

#install utility to control usb power
sudo apt-get install uhubctl

#Turn off usb (though this has no measurable effect)
sudo uhubctl -l 2 -a 0

Per this thread, it looks like I could also:
Turn off Ethernet LEDs
Turn off PI4 DRM VC4 V3D driver
disable onboard audio (Minimal to no expected change?)

Is there anything else I should be looking at? Is there a better way to disable usb to save more power?

Thanks!
Hi, do i need to put in all those commands (for Bluetooth and WiFi) in config.txt. If yes, do i just copy & paste it there? Sorry for the noob question.

Wonder if there is a way to turn off the GPIO and if there is, is there any power saving from turning it off.

Thank you in advance.
They go in a shell script that would be executed after the Pi is finished booting.
What do i do to make it work on my Pi?
Raspberry Pi OS (32-bit) with desktop and recommended software
Raspberry Pi 4 Model B 8GB at stock speed (never overclock)

Never overclock your Pi.
Encourage optimization instead.

soundcheck
Posts: 63
Joined: Thu May 21, 2015 1:36 pm
Location: DUS

Re: RPi4 - Power Savings

Sun Jul 05, 2020 5:48 pm

I tested another potential USB (controller) off option.

Code: Select all

echo 1 >/sys/bus/pci/devices/0000\:01\:00.0/remove
This does disconnect the USB controller from pci. lsusb shows no output anymore.

However. Power consumption won't change. Either the USB controller is already down.
They did try to improve a lot on the power saving within the USB controller firmware if I'm not mistaken.
Or the USB controller doesn't go into powerdown when loosing pci connection.

I also tried the latest RPI4 compatible uhubctl @ https://github.com/mvp/uhubctl

I can confirm, as somebody reported earlier. No change on idle power consumption if power is off on USB2/3.

Code: Select all

#USB2
uhubctl -l 1-1 -a 0
#USB3
uhubctl -l 2 -a 0
All uhubctl actually does is disable buspower for the USB outputs. If nothing is attached to the USB ports I wouldn't expect any change.


I also retested the halt conditions. These are now working with aarch64 default kernel (5.4.50-64) and latest firmware (pieeprom-2020-06-15.bin/000137ad)

and this bootconf (>> vcgencmd bootloader_config)

Code: Select all

[all]
BOOT_UART=0
WAKE_ON_GPIO=0
POWER_OFF_ON_HALT=1
DHCP_TIMEOUT=45000
DHCP_REQ_TIMEOUT=4000
TFTP_FILE_TIMEOUT=30000
ENABLE_SELF_UPDATE=1
DISABLE_HDMI=1
BOOT_ORDER=0xf41


You need to run a

Code: Select all


halt -p 

#or

shutdown -h now

though. That brings you down to 20mA.

IMPORTANT!!!!!!!!!

Just running

Code: Select all


halt

lets the (my) PI run at full power consumption of around 510mA!!!!
____________________________________________________________________________________
RPi 4B - Raspberry PI OS (64) (w/ custom RPiOS4 (rt-)kernel )

ejolson
Posts: 10214
Joined: Tue Mar 18, 2014 11:47 am

Re: RPi4 - Power Savings

Sun Jul 05, 2020 6:26 pm

soundcheck wrote:
Sun Jul 05, 2020 5:48 pm
You need to run a

Code: Select all


halt -p 

#or

shutdown -h now

though. That brings you down to 20mA.

IMPORTANT!!!!!!!!!

Just running

Code: Select all


halt

lets the (my) PI run at full power consumption of around 510mA!!!!
Is /sbin/poweroff the same as /sbin/halt -p or are they different?

soundcheck
Posts: 63
Joined: Thu May 21, 2015 1:36 pm
Location: DUS

Re: RPi4 - Power Savings

Sun Jul 05, 2020 7:20 pm

Havn't tested "poweroff".

man-pages state that "-p" applies to reboot, halt, poweroff
-p, --poweroff
Power-off the machine, regardless of which one of the three commands is invoked.
____________________________________________________________________________________
RPi 4B - Raspberry PI OS (64) (w/ custom RPiOS4 (rt-)kernel )

User avatar
bleep42
Posts: 257
Joined: Wed Mar 07, 2012 12:43 pm
Location: Sussex

Re: RPi4 - Power Savings

Mon Jul 06, 2020 9:08 am

Hi,
I realise for your case you require Ethernet, but does anyone know if it's possible/worthwhile turning off Ethernet to save power on a Pi4? I'm currently only using WiFi on my Pi4.
Regards, Kevin.

User avatar
bleep42
Posts: 257
Joined: Wed Mar 07, 2012 12:43 pm
Location: Sussex

Re: RPi4 - Power Savings

Mon Jul 06, 2020 9:31 am

Answering my own question slightly here, but JDB Pi Engineer said this about Ethernet.

"There are 3 ethernet PHY power states that you enter based on various conditions. The first is active/transmitting - when there is traffic, the PHY is fully powered and sending/receiving data. The second is auto-GREEN mode, where the PHY enters a transparent energy-efficient mode when there is no active traffic (stops sending idle symbols and powers down a lot of the TX circuitry, and enters a sleep mode on the RX side). This requires a compatible Energy-Efficient Ethernet link partner, but most switches implement this feature by default. The third is with the cable unplugged - the PHY enters "energy detect" idle which will completely powers down TX and most of RX, periodically waking the RX side to check for cable insertion."

soundcheck
Posts: 63
Joined: Thu May 21, 2015 1:36 pm
Location: DUS

Re: RPi4 - Power Savings

Mon Jul 06, 2020 10:54 am

I tested some more powerdown to 20 mA options:

All these worked:

Code: Select all

shutdown -h now
halt -p
poweroff
poweroff -p
All of them bring my system properly down to 20mA.

Arch Linux shutdown/halt/poweroff/reboot are linked to "systemctl". All of them are aliases. Fedora is similar.
The overall behavior might be different between OSes. Above is therefore not a guarantee that other systems behave
exactly the same way.

I btw also tried "reboot -p", since the man-page mentioned that -p applies also to reboot. That's not working.
I also tried "shutdown -p now". Here the -p option doesn't exist.

Enjoy the jungle.
____________________________________________________________________________________
RPi 4B - Raspberry PI OS (64) (w/ custom RPiOS4 (rt-)kernel )

Endgame
Posts: 32
Joined: Mon Jun 29, 2020 5:59 pm

Re: RPi4 - Power Savings

Fri Jul 10, 2020 2:31 pm

I picked up a power meter (this one to be specific: https://poniie.com/products/17), and after playing with it a little bit, I have these observations.

1) Anker customer service stated its 6 port, 60 watt power supply is 85% efficient at any load. This appears to be incorrect. 1 pi 4 4GB attached to the charger draws 5.43 watts peak running Rosetta. 5x pi 4 4GB plugged into the same charger draw 24.79 watts peak (4.958 watts each).

2) During load, multiple tweaks seem to make minimal to no difference in power utilization. Disabling USB, hdmi, and audio have no effect. Turning off the LEDs and slowing ethernet to 100mbit seem to be the most reliable way to reduce power.

3)Power optimizations on the Pi 4s that I'm testing with, in order of effectiveness:
Ethernet reduced to 100mbit
Maximum under volt (0.835v via over_voltage=-2).
disable power and network LEDs
disable hdmi / audio / usb (no measurable drop in power, or possibly even a .01 watt increase)

4) The lowest observed power draw at the meter with tweaks applied from item 3, is 4.516 watts per pi (22.58 watts total using the 5 pi setup). This is not a great showing for efficiency when compared to the newest, highest density AMD processors (3950 and higher density). In terms of Rosetta@home, that's 311 Rosetta average credit per watt at the current point values, or 243.58 RAC per watt on my values from April. To beat x86 at power efficient compute, the pi 4 would probably have needed to be on a 14nm node instead of 28nm

5) Overclocking to 2000mhz using over_volt=4 with other power optimizations in place (100mbit, disabled LEDs) pulls 6 watts (give or take a little due to Rosetta fluctuations). That is a 31% increase in clockspeed for roughly a 33% increase in power, which is actually really quite good. Unfortunately that extra clockspeed generally only results in about +20% rac in Rosetta. It's possible that performance gains may be more linear using different projects / tasks that use less ram.

Questions:

1) Does anyone know why over_volt values lower than -2 don't drop voltage below .835v?

2) What is the rated power efficiency of the official raspberry pi power supply? I would really like to find a power supply at 95% efficiency.

3) Is it possible to over / under clock and over / under volt the ram?

4) Does disabling TV service really, truly turn off everything for video? Do I need to turn off other features (frame_buffer=0 for example?) Can I power it down further?

ejolson
Posts: 10214
Joined: Tue Mar 18, 2014 11:47 am

Re: RPi4 - Power Savings

Fri Jul 10, 2020 5:30 pm

Endgame wrote:
Fri Jul 10, 2020 2:31 pm
I picked up a power meter (this one to be specific: https://poniie.com/products/17), and after playing with it a little bit, I have these observations.

1) Anker customer service stated its 6 port, 60 watt power supply is 85% efficient at any load. This appears to be incorrect. 1 pi 4 4GB attached to the charger draws 5.43 watts peak running Rosetta. 5x pi 4 4GB plugged into the same charger draw 24.79 watts peak (4.958 watts each).
That looks like the same power meter I've been using here.

viewtopic.php?p=1668056#p1668056

Why is the volt-ampere readout so different than the watts readout for the official Raspberry Pi power supply but the volt-ampere readout agrees with watts when measuring my x86 PC?

How do volt-amperes compare with watts when you are measuring the draw of the Anker power supply?

trejan
Posts: 5113
Joined: Tue Jul 02, 2019 2:28 pm

Re: RPi4 - Power Savings

Fri Jul 10, 2020 5:58 pm

ejolson wrote:
Fri Jul 10, 2020 5:30 pm
Why is the volt-ampere readout so different than the watts readout for the official Raspberry Pi power supply but the volt-ampere readout agrees with watts when measuring my x86 PC?
The Pi PSU has poor power factor as it is a SMPS which is why real power i.e. watts doesn't match up with apparent power i.e. VA. Your PC PSU will have active power factor correction circuitry. Small PSUs like phone chargers and the Pi PSU tend to not have power factor correction circuitry as they don't consume much power anyway.

Distortionist
Posts: 15
Joined: Thu Oct 22, 2020 8:16 pm

Re: RPi4 - Power Savings

Sat Nov 14, 2020 1:50 pm

Hi, I know this is old, what what is the normal running amps of a pi?

I am having trouble understanding what is going on. I have a panel connected to a charge controller and a 35mah battery.
I was using a stepdown to an extra powerbank, then from powerbank to the pi. I have some power savings features enabled like bt is disabled, so are the leds and it is underclocked.

The stepdown was reading the pi as consuming 0.05 amps, and it was reading the volts as 5.08, i had set it to 5.11 and when its under load it reads 5.8. Is it possible that the pi was consuming that few amps running? it will jump to 2.5 every now and then for a few seconds but go back down to 0.05. This was temporary gear till I got a smaller stepdown with no screen, and got rid of the extra battery pack. The controller would read the load as 0.0 or 0.1-0.3 when it would go up to 0.25 on the step down, it doesn't go to 2 decimal points.

After switching it no longer never consumes as little as it used to. I even notice it in the battery life. The new step down is tiny and doesn't have any readings, it just converts to a usb port giving 5v max 3a. The reading on the controller was constantly jumping between 0.1 and 0.2 with the new setup. Unsatisfied I thought maybe the new cable is weird, so I got the thickest cable I have that is also shorter, and switched to that. It has been more stable at 0.1 but still flicks to 0.2 every now and then.

Is that normal consumption? Why would it have been reading 0.0 even at the controller with a bigger step down with lights, and the pi, and the battery load before, and now with much less crap, its reading so much higher? The PI has nothing but a multi camera module connected to it, and 2 cameras, I have LEDs off, BT off, eth0 down, usb is off. I want it to go back to consuming 0.05a when running! It is possible I guess that when the controller is reading 0.1 it is rounding up from 0.5 I guess and before it was rounding down, I just want to know what others are getting for running consumption after putting their pi on a power diet and if I can improve. My panel is on the inside of a window in an inaccessible high spot. It doesn't get the best sun in winter. On a sunny day it can sustain the pi and keep the battery topped up each day, I am running into trouble when we have a few cloudy days in a row. I need to try to make the pi consume less. I expected it would run for a week with a 35ah battery.. I have never actually run it down, I panic when it gets to 12.7 and I climb up there and plug a charger to it. My cut off is set to 12.4.

User avatar
davidcoton
Posts: 6851
Joined: Mon Sep 01, 2014 2:37 pm
Location: Cambridge, UK

Re: RPi4 - Power Savings

Sat Nov 14, 2020 4:00 pm

Location: 345th cell on the right of the 210th row of L2 cache

Distortionist
Posts: 15
Joined: Thu Oct 22, 2020 8:16 pm

Re: RPi4 - Power Savings

Sun Nov 15, 2020 11:58 am

davidcoton wrote:
Sat Nov 14, 2020 4:00 pm
Pi Power Requirements
Ok 600ma is normal, thank you that helps a lot. It tells me there is no way I can really effectively measure my consumption with the controller, it only measures to 1 decimal point and if typical is that low I am close. It also tells me there is no way in hell the Pi was consuming 50mA, it must have been getting power from the battery bank not the stepdown/rest of the solar setup.

How come some people in this topic were getting 0.7XX in halt? That throws me off. I would have never expected normal consumption to be so low before underclocking. I have to interrupt it to measure it with my multimeter to really know I guess. I also think that cable made a significant difference switching it. My battery seems to be lasting much longer now, and the reading on the solar controler stil jumps between 2 and 1 but it is much less and spends significantly more time reading .1 than .2 which is the opposite of what it was, it was mostly 0.2 flicking to 0.1.

I wonder if I am better off switching back to the digital step down with more accurate amp reading. I switch away from it because it had an LCD backlight display that never went off and neither did the bright backlight, and it is significantly larger than the other tiny one so I thought it would be wasting more energy. Either way it is lasting much longer and I think I resolved my issue. It would be nice through to have this thread updated with all the things we can do to conserve power. I feel like the ethernet port can do better than ifconfig down, the USB still receives power after turning them off as mentioned here. I need wifi so I can't turn it off but maybe I can slow it down / lock it to a more power friendly frequency? Also shutting down the video and hdmi seem to do very little, I wonder if the chip is still powered.

piwi
Posts: 100
Joined: Fri Nov 27, 2020 11:44 am

Re: RPi4 - Power Savings

Fri Nov 27, 2020 12:13 pm

Hi folks,

it's a really interesting thread. I have a RASPI 4B running RaspiOS Lite (32BIT). My application doesn't need to much performance as I just readout data from an external asset via UART, do some processing and saving data to a DB. Also a REST API with Nginx/Gunicorn/Flask is available.
I incorporated most of the power opimizations from this thread but the system still has a fairly high consumption from my point of view in run mode (just the standard RaspiOS Lite is running). Can I reduce power consumption be reduced to ~1W?

Please see snapshot below
Voltage: 4.98V
Current: 0.359A
Power: 1.78W

My config parameter:
1-2 CPUs enabled
Audio off
turn off mainboard LEDs
disable ACT LED
disable PWR LED
turn off ethernet port LEDs
turn off bluetooth - dtoverlay=disable-bt
turn off wifi - dtoverlay=disable-wifi

arm_freq=500
arm_freq_min=200
arm_freq_max=700

DDR reduced to 512MB
raspi4.png
RASPI4 with USB Power Meter
raspi4.png (189.07 KiB) Viewed 3578 times

okina
Posts: 4
Joined: Sun Jan 31, 2021 5:47 am

Re: RPi4 - Power Savings

Wed Feb 03, 2021 2:44 pm

it's a really interesting thread. I have a RASPI 4B running RaspiOS Lite (32BIT). My application doesn't need to much performance as I just readout data from an external asset via UART, do some processing and saving data to a DB. Also a REST API with Nginx/Gunicorn/Flask is available.
I incorporated most of the power opimizations from this thread but the system still has a fairly high consumption from my point of view in run mode (just the standard RaspiOS Lite is running). Can I reduce power consumption be reduced to ~1W?
Following is just a theory and not backed by actual testing with rpi4.
Generally speaking, each CPU has kind of sweetspot regarding clock rate where the cpu can provide the highest, computational power to energy ratio.

If computational workload is fixed and you (1) set cpu clocks at some fixed point, and (2) execute the workload once, then (3) measure the power consumption for the run, (4) repeat 1-3 with different clock rate, lowest power consumption will be given at somewhere between the lowest and the highest clocks.(mostly in the middle zone)

the followings will affect where the sweetspot is:
- cpu node (14nm, 10nm, 7nm,...)
- size of die
- other hardware built in the cpu die

I guess you can find the sweetspot of rpi4 by running some benchmarks with fixed clocks if you really want to do so.
When I have time, I'll do that myself and post the results here.
You will be able to reduce the power consumption even more, using the cpu sweetspot.

Endgame
Posts: 32
Joined: Mon Jun 29, 2020 5:59 pm

Re: RPi4 - Power Savings

Wed Jun 02, 2021 6:15 pm

Bringing back this post, as I've recently been introduced to dynamic voltage frequency scaling and started looking up my clock speeds with vcgencmd, and have a questions:

Can UART, pixel, and v3d be entirely disabled, including powering off the chips?

Use case: Headless pi attempting to maximize cpu performance with minimum total power draw.

I'm currently running the following in my /boot/config.txt
dtparam=audio=off
max_framebuffers=0
arm_64bit=1
dtoverlay=disable-wifi
dtoverlay=disable-bt
gpu_mem=16
over_voltage=-2
arm_freq=1525
enable_uart=0
dvfs=1
v3d_freq=360
v3d_freq_min=50

and I see the following frequencies according to vcgencmd:

arm: frequency(48)=1525341824
core: frequency(1)=500000992
H264: frequency(0)=0
isp: frequency(45)=0
v3d: frequency(46)=250000496
uart: frequency(22)=47988280
pwm: frequency(25)=0
pixel: frequency(29)=75001464
vec: frequency(10)=0
hdmi: frequency(0)=0
dpi: frequency(4)=0

I would have guessed with 0 frame buffers / tvservice off that pixel and v3d would have been powered off, but that obviously isn't the case.

I would have thought the same with enable_uart=0 that any uart hardware would be disabled as well, but again, that obviously isn't the case.

cleverca22
Posts: 6809
Joined: Sat Aug 18, 2012 2:33 pm

Re: RPi4 - Power Savings

Wed Jun 02, 2021 8:26 pm

the PL011's arent in a dedicated power domain, so there is no way to turn them off

i would expect v3d to also be off, but i'm not sure how to read that directly, i should update my MMIO tooling to dump all of the PM regs...

Endgame
Posts: 32
Joined: Mon Jun 29, 2020 5:59 pm

Re: RPi4 - Power Savings

Wed Jun 02, 2021 9:14 pm

cleverca22 wrote:
Wed Jun 02, 2021 8:26 pm
the PL011's arent in a dedicated power domain, so there is no way to turn them off

i would expect v3d to also be off, but i'm not sure how to read that directly, i should update my MMIO tooling to dump all of the PM regs...
OK, so I won't be able to power down UART - now I'm wondering if there is any power or system advantage at all to using enable_uart=0?

Any ideas or knowledge on Pixel?

cleverca22
Posts: 6809
Joined: Sat Aug 18, 2012 2:33 pm

Re: RPi4 - Power Savings

Wed Jun 02, 2021 10:57 pm

Endgame wrote:
Wed Jun 02, 2021 9:14 pm
Any ideas or knowledge on Pixel?
i dont remember there being a pixel domain, but there is image and graphics domains
Image

its missing in this image, but the dwc usb2 controller is also in the image domain
and confusingly, a lot of image stuff (jpeg encoder) are in the audio domain

i think its named more like power levels in a cellphone
when you turn the screen off, but keep music playing, you loose the graphics and image domains
but the cpu itself is in the audio domain, and can keep doing things

something on my todo list, is to find a list of every power domain, and list what their status is

piwi
Posts: 100
Joined: Fri Nov 27, 2020 11:44 am

Re: RPi4 - Power Savings

Thu Jun 03, 2021 7:26 am

Endgame wrote:
Wed Jun 02, 2021 6:15 pm
Bringing back this post, as I've recently been introduced to dynamic voltage frequency scaling and started looking up my clock speeds with vcgencmd, and have a questions:

Can UART, pixel, and v3d be entirely disabled, including powering off the chips?

Use case: Headless pi attempting to maximize cpu performance with minimum total power draw.

I'm currently running the following in my /boot/config.txt
dtparam=audio=off
max_framebuffers=0
arm_64bit=1
dtoverlay=disable-wifi
dtoverlay=disable-bt
gpu_mem=16
over_voltage=-2
arm_freq=1525
enable_uart=0
dvfs=1
v3d_freq=360
v3d_freq_min=50

and I see the following frequencies according to vcgencmd:

arm: frequency(48)=1525341824
core: frequency(1)=500000992
H264: frequency(0)=0
isp: frequency(45)=0
v3d: frequency(46)=250000496
uart: frequency(22)=47988280
pwm: frequency(25)=0
pixel: frequency(29)=75001464
vec: frequency(10)=0
hdmi: frequency(0)=0
dpi: frequency(4)=0

I would have guessed with 0 frame buffers / tvservice off that pixel and v3d would have been powered off, but that obviously isn't the case.

I would have thought the same with enable_uart=0 that any uart hardware would be disabled as well, but again, that obviously isn't the case.
Hi,

what is the idle power consumption with these settings?


Statistik:300 MHz:98,02%, 400 MHz:0,76%, 500 MHz:1,22% (11857)

Endgame
Posts: 32
Joined: Mon Jun 29, 2020 5:59 pm

Re: RPi4 - Power Savings

Thu Jun 03, 2021 11:33 am

piwi wrote:
Thu Jun 03, 2021 7:26 am
Endgame wrote:
Wed Jun 02, 2021 6:15 pm
Bringing back this post, as I've recently been introduced to dynamic voltage frequency scaling and started looking up my clock speeds with vcgencmd, and have a questions:

Can UART, pixel, and v3d be entirely disabled, including powering off the chips?

Use case: Headless pi attempting to maximize cpu performance with minimum total power draw.

I'm currently running the following in my /boot/config.txt
dtparam=audio=off
max_framebuffers=0
arm_64bit=1
dtoverlay=disable-wifi
dtoverlay=disable-bt
gpu_mem=16
over_voltage=-2
arm_freq=1525
enable_uart=0
dvfs=1
v3d_freq=360
v3d_freq_min=50

and I see the following frequencies according to vcgencmd:

arm: frequency(48)=1525341824
core: frequency(1)=500000992
H264: frequency(0)=0
isp: frequency(45)=0
v3d: frequency(46)=250000496
uart: frequency(22)=47988280
pwm: frequency(25)=0
pixel: frequency(29)=75001464
vec: frequency(10)=0
hdmi: frequency(0)=0
dpi: frequency(4)=0

I would have guessed with 0 frame buffers / tvservice off that pixel and v3d would have been powered off, but that obviously isn't the case.

I would have thought the same with enable_uart=0 that any uart hardware would be disabled as well, but again, that obviously isn't the case.
Hi,

what is the idle power consumption with these settings?


Statistik:300 MHz:98,02%, 400 MHz:0,76%, 500 MHz:1,22% (11857)
1.84W.

I’ll refer you to here as someone else is doing the testing, and you can read about the individual tweaks and methodology too.

https://hardforum.com/threads/distribut ... 1045024630

piwi
Posts: 100
Joined: Fri Nov 27, 2020 11:44 am

Re: RPi4 - Power Savings

Thu Jun 03, 2021 11:52 am

ok thanks!

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