8x MC1 solo on a single PSU (daisychain-boot?)

Post Reply
o_lampe
Posts: 49
Joined: Wed Jan 01, 2020 12:35 am
languages_spoken: english german
ODROIDs: MC1 solo
Has thanked: 1 time
Been thanked: 4 times
Contact:

8x MC1 solo on a single PSU (daisychain-boot?)

Unread post by o_lampe » Tue Jan 07, 2020 4:51 pm

Hi folks,
I want to power my MC1's from a single 5V 30A PSU.

Would it be possible to turn off the BIG cores while booting to reduce "inrush"-current? ( Is there any significant inrush current at all? )
I think it can be done from the CLI with:

Code: Select all

echo 0 > /sys/devices/system/cpu/cpuX/online
Where X is the core 4-7.

Or could I use a GPIO pin on each MC1 solo to switch a relais ( which starts the next solo a.s.o.). Too bad there aren't any "official" GPIO pins on the MC1...

ncweiler
Posts: 1
Joined: Mon Jan 27, 2020 9:41 pm
languages_spoken: english
ODROIDs: 12x MC1
Has thanked: 0
Been thanked: 0
Contact:

Re: 8x MC1 solo on a single PSU (daisychain-boot?)

Unread post by ncweiler » Mon Jan 27, 2020 10:13 pm

20 days later...

Putting this here incase the OP is still looking for an answer and for anyone else with the same or similar question.

Option 1:
The simple option would be to get a second 5V 30A power supply and connect 4 MC1's to each power supply. This would allow all eight MC1's to startup at the same time without overloading the power supplies or going into an endless reboot due to power brownouts.

Option 2:
Get a Raspberry Pi Zero and a relay board.

Instead of a Raspberry Pi, you could use any single board computer or a microcontroller. What ever device you choose, it will need at least 8 GPIO pins (one pin per relay).

This option will require cutting some wires to connect the MC1's power input to the relays. It will also require writing a program to activate each of the relays one at a time.

Note that the Raspberry Pi will probably need to remain on after the MC1's are running to keep the relays from turning off. If the relays turn off, the MC1's will turn off.

Psuedo code:

Code: Select all

relay 1 on
2 second delay

relay 2 on
2 second delay

relay 3 on
2 second delay
Possible relay boards:
https://thepihut.com/products/8-relay-c ... spberry-pi
https://www.seeedstudio.com/Raspberry-P ... -2409.html
https://www.amazon.com/raspberry-pi-rel ... elay+board

User avatar
mad_ady
Posts: 7150
Joined: Wed Jul 15, 2015 5:00 pm
languages_spoken: english
ODROIDs: XU4, C1+, C2, N1, H2, N2, Go, Go Advance
Location: Bucharest, Romania
Has thanked: 315 times
Been thanked: 221 times
Contact:

Re: 8x MC1 solo on a single PSU (daisychain-boot?)

Unread post by mad_ady » Tue Jan 28, 2020 3:59 am

I missed the original post.
Not sure about uboot power usage, but you can boot the kernel with numcpus=1 to force only one little core on if I remember correctly. There are more details on a thread about battery powered xu4s.
You can also set systemd cpu affinity to the little cores so all processes will run on little. When you need big cores you use taskset or cgroups to restrict processes to specific cores.

o_lampe
Posts: 49
Joined: Wed Jan 01, 2020 12:35 am
languages_spoken: english german
ODROIDs: MC1 solo
Has thanked: 1 time
Been thanked: 4 times
Contact:

Re: 8x MC1 solo on a single PSU (daisychain-boot?)

Unread post by o_lampe » Tue Jan 28, 2020 4:04 pm

Thanks to both of you,
I have 4 nodes running now and the PSU 'chirps' when I switch it on, like there is no load on 5V. Same sound, when I shutdown all nodes, before I switch off the PSU.
Seems to me, there is no inrush current to be afraid off.

@mad_ady
The BOINC-client starts automatically, how would I 'taskset' it to the BIG.cores then?

User avatar
mad_ady
Posts: 7150
Joined: Wed Jul 15, 2015 5:00 pm
languages_spoken: english
ODROIDs: XU4, C1+, C2, N1, H2, N2, Go, Go Advance
Location: Bucharest, Romania
Has thanked: 315 times
Been thanked: 221 times
Contact:

Re: 8x MC1 solo on a single PSU (daisychain-boot?)

Unread post by mad_ady » Tue Jan 28, 2020 4:10 pm

Here's an idea: https://magazine.odroid.com/article/set ... rpose-nas/. Look for the cgroup section
These users thanked the author mad_ady for the post:
o_lampe (Tue Jan 28, 2020 4:13 pm)

Post Reply

Return to “Hardware and peripherals”

Who is online

Users browsing this forum: No registered users and 2 guests