Hi John, Thanks for the validation! This is what I expected. Your system has deep c-state supported now, :) Yeah, powertop doesn't work because we can't use dtrace and kmdb together. But you still can observe c-state info by kstat.
$ kstat | grep current_cstate You should see C0, C1, and C3 there. Thanks, -Aubrey John.M.Martin <> wrote: > Li, Aubrey wrote: >> >> It looks like the BIOS only support native deep cstate method. >> We probably need to enable PDC.bit9. >> >> John, could you please help to verify it on your system? >> >> 1) reboot the system and enter kmdb >> >> 2) set a breakpoint at cpu_acpi_write_pdc() >> [0]> cpu_acpi_write_pdc:b >> >> 3) continue to hit the breakpoint >> [0]> :c >> >> 4) when the breakpoint is hit, change "cpupm_intel_pdccap" to 0xBBF. >> [0]> cpupm_intel_pdccap/W 0xBBF >> >> 5) continue to boot the system. >> > FWIW, on each of the eight i7 920 "cpus", 0xbbf replaced 0x9bf. > > This experiment was more complex than anticipated. The first > breakpoint went fine. On the second breakpoint ([1]> ) no input was > accepted > on the USB console keyboard. Switching this keyboard to the PS/2 > input with a dongle fixed the problem. > > After the system booted, powertop fails with: > > powertop: ../common/cpufreq.c : cannot open dtrace library: DTrace > cannot be used when kernel debugger is active > > but "kstat cstate" now produces output (it didn't before). If it > matters, the SBIOS option is still set to "Auto". > > # kstat cstate > module: cstate instance: 1 > name: c1 class: misc > address_space_id FFixedHW > crtime 201.053737219 > latency 1 > power 1000 > snaptime 618.987573382 > > module: cstate instance: 1 > name: c3 class: misc > address_space_id FFixedHW > crtime 201.053738694 > latency 96 > power 350 > snaptime 618.987763894 > > module: cstate instance: 2 > name: c1 class: misc > address_space_id FFixedHW > crtime 235.491583585 > latency 1 > power 1000 > snaptime 618.987868627 > > module: cstate instance: 2 > name: c3 class: misc > address_space_id FFixedHW > crtime 235.491585306 > latency 96 > power 350 > snaptime 618.987962843 > > module: cstate instance: 3 > name: c1 class: misc > address_space_id FFixedHW > crtime 254.080557069 > latency 1 > power 1000 > snaptime 618.988062766 > > module: cstate instance: 3 > name: c3 class: misc > address_space_id FFixedHW > crtime 254.080558851 > latency 96 > power 350 > snaptime 618.988155771 > > module: cstate instance: 4 > name: c1 class: misc > address_space_id FFixedHW > crtime 301.460281258 > latency 1 > power 1000 > snaptime 618.98825552 > > module: cstate instance: 4 > name: c3 class: misc > address_space_id FFixedHW > crtime 301.460282866 > latency 96 > power 350 > snaptime 618.988349078 > > module: cstate instance: 5 > name: c1 class: misc > address_space_id FFixedHW > crtime 354.306818526 > latency 1 > power 1000 > snaptime 618.988449423 > > module: cstate instance: 5 > name: c3 class: misc > address_space_id FFixedHW > crtime 354.306820203 > latency 96 > power 350 > snaptime 618.988542142 > > module: cstate instance: 6 > name: c1 class: misc > address_space_id FFixedHW > crtime 373.751687887 > latency 1 > power 1000 > snaptime 618.988660284 > > module: cstate instance: 6 > name: c3 class: misc > address_space_id FFixedHW > crtime 373.751690036 > latency 96 > power 350 > snaptime 618.988753932 > > module: cstate instance: 7 > name: c1 class: misc > address_space_id FFixedHW > crtime 388.831011112 > latency 1 > power 1000 > snaptime 618.988854217 > > module: cstate instance: 7 > name: c3 class: misc > address_space_id FFixedHW > crtime 388.831013099 > latency 96 > power 350 > snaptime 618.988947075 > > #