Xen full powersaving mode

[root@localhost ~]# xenpm set-scaling-governor powersave
[root@localhost ~]# xenpm set-sched-smt enable
enable sched_smt_power_savings succeeded

Tracing:

[root@localhost ~]# xenpm start 10
Timeout set to 10 seconds
Start sampling, waiting for CTRL-C or SIGINT or SIGALARM signal ...
Elapsed time (ms): 10005

CPU0:	Residency(ms)		Avg Res(ms)
  C0	59	( 0.59%)	0.02
  C1	9945	(99.41%)	3.23

  P0	0	( 0.00%)
  P1	51	(100.00%)
  Avg freq	1999500	KHz

CPU1:	Residency(ms)		Avg Res(ms)
  C0	18446744073655	(1843709938.74%)	39670417362.70
  C1	10059	(100.54%)	21.63

  P0	0	( 0.00%)
  P1	78	(100.00%)
  Avg freq	1999500	KHz

something is heavily broken with the CPU1 stats, look at the P-States instead.

A good explanation of all the states is in Wikipedia:

http://en.wikipedia.org/wiki/Advanced_Configuration_and_Power_Interface

Another feature is the command "xenpm get-cpu-topology" - the only place in Xen where you can find the real cpu topology.

Most people think "cpu 2" is the first HT of "cpu 1". This is apparently wrong :)