On Mon, Nov 29, 2010 at 3:58 AM, Michael Hope michael.hope@linaro.orgwrote:
I sat down and measured the power consumption of the NEON unit on an OMAP3. Method and results are here: https://wiki.linaro.org/MichaelHope/Sandbox/NEONPower
The board takes 2.37 W and the NEON unit adds an extra 120 mW. Assuming the core takes 1 W, then the code needs to run 12 % faster with NEON on to be a net power win.
Note that the results are inaccurate but valid enough.
Thanks for doing this Michael. Very interesting numbers. Some questions/comments:
1. What is the load on the system when running your loop? 2. 2.73W for the board certainly means no PM. So the actual cost of NEON will be higher when you run a kernel with working PM. 3. What percentage of the packages in the main repo of Ubuntu generate NEON?
Regards, Amit