Messages in this thread | | | From | "Etienne Lorrain" <> | Date | Mon, 18 May 1998 16:16:00 +0001 | Subject | Re: Cyrix 6x86MX and Centaur C6 CPUs in 2.1.102 |
| |
Hi,
> > > IMHO this is a trade-off. If one wants to have the processor dissipating > > > < 150mW when Linux is idle, one has to power down the 200MHz or so > > > 64-bit TSC counter circuitry. > > > > The Centaur doesnt have this bug and still has a low power mode. They do > > it right. So it is a bug in the Cyrix chip. > > The Centaur C6, just like the Intel CPUs, enters a low power mode when > the CPU executes a HALT instruction (i.e. when Linux is idle). However, > it is not the same low power mode as found in the Cyrix 6x86 CPUs. > > Just like the Intel and the AMD K5/K6 chips, the Centaur C6 will still > dissipate around 2.5 Watts in this low power mode. > > OTOH when the clock is _stopped_ (e.g. APM), the Centaur, just like the > Intel and the AMD K5/K6, will dissipate around 350 mW. However, coming > out of a clock stop condition is expensive in terms of clock cycles, > because the CPU internal clock PLL must re-synchronize with the external > clock input.
Just to add few words on this thread:
Are you sure that stopping and restarting a 200 MHz oscillator nearly 100 times per second does not consume more power than staying in idle mode ?
Maybe this feature will be a lot more interresting when the variable HZ will be configurable at runtime (while not doing anything, Hz could go down to 10 or less), but for now I just would like to compare stanby time of battery powered PC.
Just my Euro 0.02, Etienne.
----------- etienne.lorrain@ibm.net -- hdc: irq timeout: status=0xd0 { Busy } -- ide1: reset: success ----------> I like Linux !
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu
| |