On Mon, Jul 12, 2010 at 05:23:23PM +0200, Markus Gebert wrote: > > On 12.07.2010, at 17:06, John Baldwin wrote: > > > Are you using Cx states other than C1 for the CPUs at all? > > Not sure how to find out, but I did not change anything in the BIOS settings > (if even possible) or through sysctl regarding cpu idle modes. Anyway, here's > what I found: > > # sysctl machdep.idle machdep.idle_available > machdep.idle: amdc1e > machdep.idle_available: spin, amdc1e, hlt, acpi, > > Not sure if "amdc1e" qualifies for something "other than C1". I tried "hlt" > once, which didn't make a difference IIRC. And if that's not what you needed, > here's more: > > # sysctl dev.cpu > [...] > dev.cpu.0.freq_levels: 2786/95000 2587/81800 2388/69811 2189/58977 1990/49240 > 1791/44316 995/22525 > dev.cpu.0.cx_supported: C1/0 > dev.cpu.0.cx_lowest: C1 > [...]
cx_supported indicates your CPU only supports C1 and not lower power-saving states (C2/C3/C4, etc.). Non-C1 states can sometimes do "interesting" things when it comes to interrupt handling. I believe your system may support the C1E state (given what machdep.idle_available shows), but that's often controlled by the system BIOS (on both Intel and AMD processors, but I'm trying to focus on AMD here). C1E, as far as I know, is the same as C1 state except can save a little bit more power. I believe neither C1 nor C1E do anything with interrupts, instead just halting the core when idle/not in use. HLT mode, at least on multi-core AMD CPUs, equates to C1E. Shot in the dark: you're not running powerd(8) on this system are you? -- | Jeremy Chadwick j...@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB | _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
