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The values are computed from measuring energy over a 10 secs sysbench
workload running at each frequency and affine to 1 or 2 A15's as well as
1 or 2 or 3 A7's. The Power values for individual cpus are calculated
from the Energy values divided by workload runtime by taking the
difference of the energy values between n+1 and n cpus.
P [mW] = C * freq [Mhz] * voltage [mV] * voltage [mV] / 1000000000
C = P [mW] / (freq [Mhz] * voltage [mV] * voltage [mV]) * 1000000000
The actual C (dynamic-power-coefficient) value is the mean value out of
all the C values of the OPP's.
A15:
freq power voltage dyn_pwr_coef
[MhZ] [mW] [mV]
0 500.0 534.57550 900 1319.939506
1 600.0 547.15468 900 1125.832675
2 700.0 572.22060 900 1009.207407
3 800.0 607.76592 900 937.910370
4 900.0 648.50552 900 889.582332
5 1000.0 693.86776 900 856.626864
6 1100.0 916.51314 975 876.469442
7 1200.0 1198.57566 1050 905.952880
mean: 990
A7:
freq power voltage dyn_pwr_coef
[MhZ] [mW] [mV]
0 350.0 40.17430 900 141.708289
1 400.0 42.68700 900 131.750000
2 500.0 54.25716 900 133.968296
3 600.0 64.09914 900 131.891235
4 700.0 74.09736 900 130.683175
5 800.0 82.69694 900 127.618735
6 900.0 113.71386 975 132.911225
7 1000.0 144.94124 1050 131.465977
mean: 133
The ratio between A15 and A7 is 990/113 = 7.44
This value (7.44) is very close to mean ratio between the power value of
A15 an A7 of the per sched-domain Energy Model (7.96):
mV Mhz MhZ old EM ratio
A7 A15 core power
900 350 500 6997/1024 6.83
900 400 600 5177/761 6.80
900 500 700 3846/549 7.01
900 600 800 3524/447 7.88
900 700 900 3125/407 7.68
900 800 1000 2756/334 8.25
975 900 1100 2312/275 8.40
1050 1000 1200 2021/187 10.80
mean: 7.96
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Change-Id: I93ef375d05ff769481a07f2c74f061e307cb14d4
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.