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Old 2019-01-30, 12:26   #51
M344587487's Avatar
"Composite as Heck"
Oct 2017

3×311 Posts

I've made a few scripts to help anyone that wants to convert a big.LITTLE device into an mlucas compute node. Only tested on two S7 Edge's so far:
  • The setup script takes a user defined description of the clusters in the format used by mlucas's -cpu flag (the description for each cluster is passed verbatim to mlucas), creates the worker directories, generates the mlucas.cfg for each cluster with the other clusters under load, and modifies the timings in mlucas.cfg to be contiguous as they're unreliable as generated due to potential aggressive governor behaviour on big.LITTLE devices.
  • The bench script performs a 20 hour simultaneous FFT benchmark test with 1024K (1 hour), 2560K (2 hours), 4608K (3 hours), 7680K (4 hours) and 18432K (10 hours) FFT lengths, putting the results and a few vitals from the device into a tarball.

Originally Posted by Mark Rose View Post
Do you have any idea how many watts they're drawing?
Under the same conditions as the above test (wind tunnel, screen permanently on at minimal brightness, fully charged battery) with simultaneous 1024K runs, device B is bouncing between 4.5W and 8.0W. Not including the PC fan which is powered by a PC PSU. The wattmeter has a resolution of 0.5W, showing 0.0W with nothing plugged in and 0.5W with the 5V/12A USB hub plugged in with no devices attached. The simultaneous 1024K test is running for a while so that an average can be generated however the KWh resolution is 0.01, it'll take a while to tick over and may take longer for an accurate result.

Originally Posted by retina View Post
I suggest that if you use these things long term 24/7 at raised temperatures to remove the battery. And if you still need to cover power outages then connect the PSU to a UPS. Small sized UPSes are easy to find.
Good point. These devices are not meant to have the battery removed so I don't know if they remain powered without one. Failing that there are apps that limit how charged the battery can get.

Originally Posted by xilman View Post
That's bloody hot!
It's ok I'm using oven gloves ;)
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