On 3 July 2013 16:48, Renato Golin renato.golin@linaro.org wrote:
On 3 July 2013 15:59, Mans Rullgard mans.rullgard@linaro.org wrote:
An OMAP4460 will run at 1.2GHz indefinitely without overheating in reasonable ambient temperature.
If you don't have thermal management in the kernel you're running, you need to clamp the clock at a safe value.
I'd expect that Linaro's kernel on Ubuntu 13.03 already had a decent thermal control of the Panda. I can get the temperatures without special code, so I assume the kernel knows precisely what to do, and I also hope that the kernel can do scheduling, otherwise, what's the point of measuring temperatures...
But more to the point, I don't want to be scaled down when hot, I want it never to get hot in the first place, so I can run at full 1.2GHz, 24 / 7. If the scheduler reduces the frequency to decrease the temperature, I'll be testing more commits per run AND my benchmarks will be skewed, depending on room temperature, which is the same as to say they're not benchmarks at all.
I repeat, the 4460 will run at 1.2GHz indefinitely without thermal management. 1.4GHz and higher _does_ require active thermal management, and I would not assume that a random kernel has this feature enabled merely because it can report the temperature.
If you want to run benchmarks on this chip, you must do so at no higher than 1.2GHz. The chip is designed for phones/tablets where high CPU load typically only occurs in short bursts.