ejolson wrote: ↑Tue May 14, 2019 8:24 am
I suspect you have misidentified which cores are the little ones
This is quite likely. All I went on was this comment in boot.ini (the equivalent of config.txt).
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# max cpu-cores
# Note:
# CPU's 0 and 1 are the A53 (small cores)
# CPU's 2 to 5 are the A73 (big cores)
# Lowering this value disables only the bigger cores (the last cores).
# setenv maxcpus "4"
# setenv maxcpus "5"
setenv maxcpus "6"
They run at different speeds: A73's are clocked at 1800MHz, the A53's are clocked at 1896MHz.
ejolson wrote: ↑Tue May 14, 2019 8:24 am
however, some sort of throttling could also be involved.
The N2 is claimed not to throttle.
It is12nm and has a really massive heat sink factory fitted.
Here are the six runs with increasing CPU counts (count: Pi Ratio)
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1: 3.06463
2: 4.50112
3: 17.1603
4: 25.8384
5: 31.6286
6: 41.9504
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odroid@odroid:~/pichart-30$ taskset -c 0 ./pichart-openmp "N2"
pichart -- Raspberry Pi Performance OPENMP version 30
Prime Sieve P=14630843 Workers=2 Sec=3.83186 Mops=243.832
Merge Sort N=16777216 Workers=2 Sec=5.2353 Mops=76.9112
Fourier Transform N=4194304 Workers=2 Sec=13.3536 Mflops=34.5506
Lorenz 96 N=32768 K=16384 Workers=2 Sec=14.7099 Mflops=218.983
My Computer has Raspberry Pi ratio=3.06463
Making pie charts...done.
odroid@odroid:~/pichart-30$ taskset -c 0,1 ./pichart-openmp "N2"
pichart -- Raspberry Pi Performance OPENMP version 30
Prime Sieve P=14630843 Workers=2 Sec=1.92459 Mops=485.469
Merge Sort N=16777216 Workers=2 Sec=4.19914 Mops=95.8895
Fourier Transform N=4194304 Workers=2 Sec=9.09953 Mflops=50.703
Lorenz 96 N=32768 K=16384 Workers=1 Sec=11.5153 Mflops=279.735
My Computer has Raspberry Pi ratio=4.50112
Making pie charts...done.
odroid@odroid:~/pichart-30$ taskset -c 0,1,2 ./pichart-openmp "N2"
pichart -- Raspberry Pi Performance OPENMP version 30
Prime Sieve P=14630843 Workers=6 Sec=1.2032 Mops=776.534
Merge Sort N=16777216 Workers=6 Sec=1.29098 Mops=311.897
Fourier Transform N=4194304 Workers=6 Sec=1.51315 Mflops=304.91
Lorenz 96 N=32768 K=16384 Workers=6 Sec=1.70545 Mflops=1888.78
My Computer has Raspberry Pi ratio=17.1603
Making pie charts...done.
odroid@odroid:~/pichart-30$ taskset -c 0,1,2,3 ./pichart-openmp "N2"
#pichart -- Raspberry Pi Performance OPENMP version 30
Prime Sieve P=14630843 Workers=8 Sec=0.796118 Mops=1173.61
Merge Sort N=16777216 Workers=4 Sec=0.966202 Mops=416.738
Fourier Transform N=4194304 Workers=8 Sec=1.11916 Mflops=412.248
Lorenz 96 N=32768 K=16384 Workers=8 Sec=0.905878 Mflops=3555.91
My Computer has Raspberry Pi ratio=25.8384
Making pie charts...done.
odroid@odroid:~/pichart-30$ taskset -c 0,1,2,3,4 ./pichart-openmp "N2"
pichart -- Raspberry Pi Performance OPENMP version 30
Prime Sieve P=14630843 Workers=10 Sec=0.594597 Mops=1571.36
Merge Sort N=16777216 Workers=10 Sec=0.776335 Mops=518.659
Fourier Transform N=4194304 Workers=10 Sec=0.997077 Mflops=462.726
Lorenz 96 N=32768 K=16384 Workers=10 Sec=0.754667 Mflops=4268.41
My Computer has Raspberry Pi ratio=31.6286
Making pie charts...done.
odroid@odroid:~/pichart-30$ taskset -c 0,1,2,3,4,5 ./pichart-openmp "N2"
pichart -- Raspberry Pi Performance OPENMP version 30
Prime Sieve P=14630843 Workers=6 Sec=0.478357 Mops=1953.2
Merge Sort N=16777216 Workers=12 Sec=0.579982 Mops=694.251
Fourier Transform N=4194304 Workers=12 Sec=0.852847 Mflops=540.98
Lorenz 96 N=32768 K=16384 Workers=12 Sec=0.474342 Mflops=6790.93
My Computer has Raspberry Pi ratio=41.9504
Making pie charts...done.
The number of workers doesn't seem to correlate with the number of CPU cores?