[Bug 11170] New: 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless

[Bug 11170] New: 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=11170

           Summary: 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless
           Product: Power Management
           Version: 2.5
     KernelVersion: 2.6.25.12-62.fc8
          Platform: All
        OS/Version: Linux
              Tree: Fedora
            Status: NEW
          Severity: normal
          Priority: P1
         Component: cpufreq
        AssignedTo: cpufreq@www.linux.org.uk
        ReportedBy: theholyettlz@googlemail.com


Latest working kernel version: 2.6.24.7-92.fc8

Earliest failing kernel version: 2.6.25

Distribution: Fedora 8

Hardware Environment: Intel Core 2 Duo T8100 on Clevo M720R notebook

Software Environment: i686

Problem Description:
Kernel 2.6.24.7 runs cooler on this machine, even when booted "nohz=off", than
Kernel 2.6.25.* in tickless mode. The difference, in both coretemp and ACPI
thermal zone, is typically 4-6 C. This is all the more odd since 2.6.25 seems
to better support ACPI features like the lid and sleep button, which were
detected under 2.6.24 but didn't generate events, and the "smart power" button
which limits the clock to 1.2 GHz. [I'm booting "nohz=off" due to another
problem whereby the machine seems to "pause" (*not* freeze) when there are few
interrupts happening.]

Under 2.6.24.7, powertop reports 100% "C0 (cpu running)" residency, just
altering the clock rate, and around 100-200 wups. With 2.6.25.12, it shows two
C0 states, "C0 (cpu running)" and just "C0"; the residency figures don't make
much sense, and I suspect powertop is reporting garbage in both cases
(sometimes things like 8 wups). Furthermore, I don't really understand what I
see in /proc/acpi/processor/*/power --- with 2.6.24.7, only C1 shows any usage,
and the number keeps resetting after a few seconds. With 2.6.25.12, C1--C3 show
some usage, again with the numbers resetting.

Another thing (I don't know if it's related) is that under 2.6.25.12, I get the
following in dmesg:

    ACPI Exception (thermal-0457): AE_ERROR, ACPI thermal trip point state
changed

I also see a lot of

    ACPI: Invalid passive threshold

in dmesg for 2.6.24.7 if I cold-boot 2.6.25.12 first. Furthermore, cold-booting
2.6.25.12 and then re-booting into 2.6.24.7 makes the lid work under the
latter.


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[Bug 11170] 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=11170


bunk@kernel.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bunk@kernel.org
         Regression|0                           |1




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[Bug 11170] 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=11170


trenn@suse.de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |trenn@suse.de,
                   |                            |rui.zhang@intel.com




------- Comment #1 from trenn@suse.de  2008-07-28 03:56 -------
Please provide acpidump and dmesg.
This should be assigned to the ACPI and not Power Management component. I
cannot change it.


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[Bug 11170] 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=11170





------- Comment #2 from theholyettlz@googlemail.com  2008-07-30 06:35 -------
Created an attachment (id=17030)
 --> (http://bugzilla.kernel.org/attachment.cgi?id=17030&action=view)
acpidump output for this machine


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[Bug 11170] 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=11170





------- Comment #3 from theholyettlz@googlemail.com  2008-07-30 06:35 -------
Created an attachment (id=17031)
 --> (http://bugzilla.kernel.org/attachment.cgi?id=17031&action=view)
dmesg output with kernel 2.6.24.7-92.fc8


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[Bug 11170] 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=11170


theholyettlz@googlemail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|cpufreq                     |Power-Processor
            Product|Power Management            |ACPI




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[Bug 11170] 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless

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------- Comment #4 from yakui.zhao@intel.com  2008-08-03 22:58 -------
Will you please attach the following outputs?
    acpidump --addr 0x7f6d4e23 --length 0x2A8 -o cpu0ist
    acpidump --addr 0x7f6d50cb --length 0xb1  -o cpu1ist
    acpidump --addr 0x7f6d48f4 --length 0x4aa -o cpu0cst
    acpidump --addr 0x7f6d4d9e --length 0x85  -o cpu1cst  

Thanks.


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[Bug 11170] 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless

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http://bugzilla.kernel.org/show_bug.cgi?id=11170


yakui.zhao@intel.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |acpi-
                   |                            |bugzilla@lists.sourceforge.n
                   |                            |et




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