Bug 11170 - 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless
Summary: 2.6.24 w/ nohz=off runs cooler than 2.6.25 tickless
Status: CLOSED INSUFFICIENT_DATA
Alias: None
Product: ACPI
Classification: Unclassified
Component: Power-Processor (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: cpufreq
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2008-07-27 05:09 UTC by James Ettle
Modified: 2009-01-30 01:38 UTC (History)
4 users (show)

See Also:
Kernel Version: 2.6.25.12-62.fc8
Subsystem:
Regression: Yes
Bisected commit-id:


Attachments
acpidump output for this machine (138.28 KB, text/plain)
2008-07-30 06:35 UTC, James Ettle
Details
dmesg output with kernel 2.6.24.7-92.fc8 (33.53 KB, text/plain)
2008-07-30 06:35 UTC, James Ettle
Details
cpu0cst from kernel-2.6.25.14-67.fc8 (1.17 KB, application/octet-stream)
2008-08-04 08:11 UTC, James Ettle
Details
cpu0ist from kernel-2.6.24.7-92.fc8 (680 bytes, application/octet-stream)
2008-08-04 08:11 UTC, James Ettle
Details
cpu0ist from kernel-2.6.25.14-67.fc8 (680 bytes, application/octet-stream)
2008-08-04 08:12 UTC, James Ettle
Details
cpu1cst from kernel-2.6.25.14-67.fc8 (133 bytes, application/octet-stream)
2008-08-04 08:12 UTC, James Ettle
Details
cpu1ist from kernel-2.6.25.14-67.fc8 (177 bytes, application/octet-stream)
2008-08-04 08:12 UTC, James Ettle
Details
2.6.24 output, AC power (755 bytes, text/plain)
2008-09-12 02:43 UTC, James Ettle
Details
2.6.26 output, AC power (878 bytes, text/plain)
2008-09-12 02:43 UTC, James Ettle
Details
2.6.24 output, battery power (755 bytes, text/plain)
2008-09-12 02:43 UTC, James Ettle
Details
2.6.26 output, battery power (877 bytes, text/plain)
2008-09-12 02:44 UTC, James Ettle
Details
Comment #18 requested data on 2.6.27.4-26.fc9.x86_64 w/ ondemand governor (1.32 KB, text/plain)
2008-11-07 01:28 UTC, James Ettle
Details
Comment #18 requested data on 2.6.27.4-26.fc9.x86_64 w/ powersave governor (1.32 KB, application/octet-stream)
2008-11-07 01:29 UTC, James Ettle
Details

Description James Ettle 2008-07-27 05:09:05 UTC
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.
Comment 1 Thomas Renninger 2008-07-28 03:56:54 UTC
Please provide acpidump and dmesg.
This should be assigned to the ACPI and not Power Management component. I cannot change it.
Comment 2 James Ettle 2008-07-30 06:35:16 UTC
Created attachment 17030 [details]
acpidump output for this machine
Comment 3 James Ettle 2008-07-30 06:35:49 UTC
Created attachment 17031 [details]
dmesg output with kernel 2.6.24.7-92.fc8
Comment 4 ykzhao 2008-08-03 22:58:35 UTC
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.
Comment 5 James Ettle 2008-08-04 08:10:54 UTC
I ran the above commands under both kernels 2.6.24.7-92.fc8 and 2.6.25.14-67.fc8. cpu0ist was different between kernel versions, so I have posted both here. The other files were the same and I've posted the ones obtained under 2.6.25.14.
Comment 6 James Ettle 2008-08-04 08:11:37 UTC
Created attachment 17080 [details]
cpu0cst from kernel-2.6.25.14-67.fc8
Comment 7 James Ettle 2008-08-04 08:11:56 UTC
Created attachment 17081 [details]
cpu0ist from kernel-2.6.24.7-92.fc8
Comment 8 James Ettle 2008-08-04 08:12:12 UTC
Created attachment 17082 [details]
cpu0ist from kernel-2.6.25.14-67.fc8
Comment 9 James Ettle 2008-08-04 08:12:33 UTC
Created attachment 17083 [details]
cpu1cst from kernel-2.6.25.14-67.fc8
Comment 10 James Ettle 2008-08-04 08:12:54 UTC
Created attachment 17084 [details]
cpu1ist from kernel-2.6.25.14-67.fc8
Comment 11 James Ettle 2008-08-04 12:18:29 UTC
Some extra info, don't know if it's related. Another thing I've just noticed with 2.6.25.14-67.fc8 is that it no longer limits the CPU clock to 1.2 GHz on battery power or when the "smart power" button is pressed. 
Comment 12 Zhang Rui 2008-09-07 23:21:40 UTC
please attach the result of
"grep . /sys/devices/system/cpu/cpu0/cpufreq/*" on both 2.6.25 and 2.6.24 kernel.
Comment 13 James Ettle 2008-09-12 02:41:32 UTC
I've attached the requested data from kernel-2.6.24.7-92.fc8 and kernel-2.6.26.3-14.fc8, both on battery and AC power.
Comment 14 James Ettle 2008-09-12 02:43:01 UTC
Created attachment 17743 [details]
2.6.24 output, AC power
Comment 15 James Ettle 2008-09-12 02:43:27 UTC
Created attachment 17744 [details]
2.6.26 output, AC power
Comment 16 James Ettle 2008-09-12 02:43:54 UTC
Created attachment 17745 [details]
2.6.24 output, battery power
Comment 17 James Ettle 2008-09-12 02:44:45 UTC
Created attachment 17746 [details]
2.6.26 output, battery power
Comment 18 Zhang Rui 2008-09-15 19:10:46 UTC
comment #14 and #15 shows that cpu is running in 800000 in 2.6.26 and 21010000 in 2.6.24.
First, please use the "powersave" governor in both 2.6.24 and 2.6.26.
if the problem still exists, please run "grep . /sys/devices/system/cpu/cpu0/cpuidle/*/*" and attach the result.
Comment 19 Zhang Rui 2008-11-06 23:23:05 UTC
no response from bug reporter for over two months.
James,
please re-open it if you can provide the info listed in comment #18
Comment 20 James Ettle 2008-11-07 01:27:10 UTC
Hi --- sorry for neglecting you. I've just started a new job and this has kept me rather busy.

On this bug: it *appears* to be cured in (at least) 2.6.26.7 on x86-64; I'm now using 2.6.27.4 which at idle cools down to the point where the fan turns off.

I'll attached the above-requested anyway in case it is of some use.
Comment 21 James Ettle 2008-11-07 01:28:45 UTC
Created attachment 18726 [details]
Comment #18 requested data on 2.6.27.4-26.fc9.x86_64 w/ ondemand governor
Comment 22 James Ettle 2008-11-07 01:29:04 UTC
Created attachment 18727 [details]
Comment #18 requested data on 2.6.27.4-26.fc9.x86_64 w/ powersave governor
Comment 23 James Ettle 2008-11-07 01:30:42 UTC
Unfortunately, since upgrading to Fedora 9 I no longer have access to the 2.6.24 kernel... I'll close it a fixed for the time being.
Comment 24 James Ettle 2009-01-30 01:38:05 UTC
For further reference: this appears to be fixed for now. Thanks!

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