Re: XEN increases idle power consumption by 25%

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, Aug 30, 2011 at 02:19:17PM +0200, Martin Meier wrote:
> On Mon, Aug 29, 2011 at 10:09 PM, Konrad Rzeszutek Wilk
> <konrad.wilk@oracle.com> wrote:
> > On Mon, Aug 29, 2011 at 05:30:58PM +0200, Martin Meier wrote:
> >> On Thu, Aug 25, 2011 at 12:25 AM, Konrad Rzeszutek Wilk
> >> <konrad.wilk@oracle.com> wrote:
> >>
> >> > And you can test the xen-cpu-idle patches in #testing if you are up for
> >> > seeing if that is the cause of your power consumption issues.
> >> >
> >> > git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git #testing
> >>
> >> OK, I switched from 3.1-rc2 to your 3.0.3 kernel - I now see ~23W w/
> >> or w/o xen :-)
> >
> > Ok, so that is the #master branch right? And ~23W was what you wanted
> > right?
> 
> Yes, and yes.
> 
> I tried #testing today and it worked OK, too.
> 
> FYI, after a minor change to the kernel .config:
> 
> -CONFIG_ACPI_PROCESSOR=y
> +CONFIG_ACPI_PROCESSOR=m
> 
> -CONFIG_ACPI_PROCESSOR_XEN=y
> +CONFIG_ACPI_PROCESSOR_XEN=m

Ah, so the baremetal processor gets in first and then the Xen
can't register. 
> 
> I noticed this:
> 
> [   11.698368] ------------[ cut here ]------------
> [   11.698386] WARNING: at drivers/cpuidle/driver.c:62
> cpuidle_unregister_driver+0x2a/0x61()
> [   11.698392] Hardware name:
> [   11.698396] invalid cpuidle_unregister_driver(acpi_idle)
> [   11.698400] Modules linked in: processor(+) snd evdev soundcore
> i2c_i801 rtc_cmos psmouse pcspkr serio_raw acpi_processor
> snd_page_all]
> [   11.698451] Pid: 560, comm: modprobe Tainted: G         C
> 3.1.0-rc4-konrad-1+ #17
> [   11.698456] Call Trace:
> [   11.698465]  [<ffffffff810587c3>] warn_slowpath_common+0x80/0x98
> [   11.698471]  [<ffffffffa0117000>] ? 0xffffffffa0116fff
> [   11.698501]  [<ffffffff8105886f>] warn_slowpath_fmt+0x41/0x43
> [   11.698508]  [<ffffffff8132959b>] cpuidle_unregister_driver+0x2a/0x61
> [   11.698516]  [<ffffffffa01170e3>] acpi_processor_init+0xe3/0xe8 [processor]
> [   11.698524]  [<ffffffff8100207a>] do_one_initcall+0x7a/0x150
> [   11.698531]  [<ffffffff8108d968>] sys_init_module+0x7e/0x1c7
> [   11.698539]  [<ffffffff813de7d2>] system_call_fastpath+0x16/0x1b
> [   11.698543] ---[ end trace f1b3f5c476845ee5 ]---
> 
> and a high idle power consumption again.

Yup. That would be happen. Thanks for testing that. Will have to
find some way of making the Xen one run first. Or deregistering
the baremetal one perhaps.