David Woolley wrote: > Evandro Menezes wrote: > >> >> And, please, don't consider the power used by NTP itself, but rather >> the power used by the CPU idling in a higher power state than before >> NTP woke it up. Modern processors can draw 100W without doing >> anything useful, but it falls down to less than 10W it it's allowed >> run the HALT instruction instead when there's nothing to do. > > > HLT instructions are a complete red herring here. They've been available Modern CPUs, chipsets and OSes have a wide range of features to manage power _and_ these are heavily used on any platform, be it PDA, Laptop, embedded device .. or Numbercrunching Cluster.
> > But you've already told us that you get a 90% power saving before you go > to the deep state. In my view, a server that is running at a > sufficiently low CPU load that going deeper that HLT is useful is badly > over-dimensioned. The current trend seems to be dedicated boxes or myriads of "VM-boxes" on a mainframe which depends heavily on a VM-box being suspended when it is idle. I haven't looked into how the VM people handle timekeeping though. > > If high load depends on time of day, you will have to dimension air > conditioning for peak loading (which means times when you will never go .............................. > efficiency costs. I am not into collocation management, but: My guess is that the required power and AC scaling is similar to what you get in telephone exchange scaling ( i.e. it evens out rather fast across all boxes. Primary issue is simultaneous PowerUp for a complete site. ( You fix that via staging ) > > Tactics for smoothing the load and achieving high productive utilisation > where common when capital cost was the main issue. Cost distribution has changed. boxes are cheap, manpower not, energy costs are rising fast. uwe _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
