Sunday, March 18, 2012

Making a Vacation

Far away from the Internet and cellular networks. Crossing the Great Baikal Lake on a bicycle.

Of course the spikes are required

A couple more pictures

Saturday, March 3, 2012

Power management in SPARC & Solaris

Few days ago someone asked me in the comments to the How-To post, whether there is a way to reduce CPU consumption of the qemu-system-sparc. I assumed qemu lacks some device necessary for the power management. So, if we implement it, qemu-system-sparc won't take 100% of CPU all the time.

And then after looking at the qemu source I was really surprised: qemu does emulate the 'power-management' device. The reason why Solaris consumes so much CPU is Solaris itself! It's just doesn't have a driver for the 'power-management' device on SPARCStation-5. In all 'prtconf' outputs I could google out, there is a line:

power-management (driver not attached)

And then comes a bigger surprise: Linux perfectly supports CPU power management on SPARCStation-5. Even under qemu: after Debian/SPARC is booted, 'top' shows that qemu-system-sparc takes only 3% of a host  CPU.
How came that Sun didn't support CPU power management on their own sun4m machines?

P.S. By the way, NetBSD supports CPU power management too.