Posted Feb 12, 2009 17:59 UTC (Thu) by anton
In reply to: FOSDEM09: "Aggressive" Linux power management
Parent article: FOSDEM09: "Aggressive" Linux power management
Why doesn't the 'race-to-idle' concept apply to GPUs?
It does not apply in general to CPUs, either. E.g., my current
desktop draws 100W idle, 111W at load 1 2GHz, and 123W at load 1 3GHz.
If I have a job that consumes 6G cycles every 3s, then at race-to-idle
3GHz it will consume (123*2+100)/3=115W, whereas at 2GHz it will
Race-to-idle may work on systems that really power down at idle,
but for most of the systems
I have measured this does not happen to a significant extent, and
the effects of voltage scaling dominate, making it beneficial to run
at the lowest clock and voltage that is sufficient for the load.
to post comments)