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7 commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Corrado Zoccolo
|
672917dcc7 |
cpuidle: menu governor: reduce latency on exit
Move the state residency accounting and statistics computation off the hot exit path. On exit, the need to recompute statistics is recorded, and new statistics will be computed when menu_select is called again. The expected effect is to reduce processor wakeup latency from sleep (C-states). We are speaking of few hundreds of cycles reduction out of a several microseconds latency (determined by the hardware transition), so it is difficult to measure. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Len Brown <len.brown@intel.com> Cc: Adam Belay <abelay@novell.com Acked-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Arjan van de Ven
|
69d25870f2 |
cpuidle: fix the menu governor to boost IO performance
Fix the menu idle governor which balances power savings, energy efficiency and performance impact. The reason for a reworked governor is that there have been serious performance issues reported with the existing code on Nehalem server systems. To show this I'm sure Andrew wants to see benchmark results: (benchmark is "fio", "no cstates" is using "idle=poll") no cstates current linux new algorithm 1 disk 107 Mb/s 85 Mb/s 105 Mb/s 2 disks 215 Mb/s 123 Mb/s 209 Mb/s 12 disks 590 Mb/s 320 Mb/s 585 Mb/s In various power benchmark measurements, no degredation was found by our measurement&diagnostics team. Obviously a small percentage more power was used in the "fio" benchmark, due to the much higher performance. While it would be a novel idea to describe the new algorithm in this commit message, I cheaped out and described it in comments in the code instead. [changes since first post: spelling fixes from akpm, review feedback, folded menu-tng into menu.c] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Len Brown <lenb@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Pallipadi, Venkatesh
|
816bb611e4 |
cpuidle: Add decaying history logic to menu idle predictor
Add decaying history of predicted idle time, instead of using the last early wakeup. This logic helps menu governor do better job of predicting idle time. With this change, we also measured noticable (~8%) power savings on a DP server system with CPUs supporting deep C states, when system was lightly loaded. There was no change to power or perf on other load conditions. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> |
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|
venkatesh.pallipadi@intel.com
|
320eee7763 |
cpuidle: Menu governor fix wrong usage of measured_us
There is a bug in menu governor where we have if (data->elapsed_us < data->elapsed_us + measured_us) with measured_us already having elapsed_us added in tickless case here unsigned int measured_us = cpuidle_get_last_residency(dev) + data->elapsed_us; Also, it should be last_residency, not measured_us, that need to be used to do comparing and distinguish between expected & non-expected events. Refactor menu_reflect() to fix these two problems. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Wei Gang <gang.wei@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> |
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venkatesh.pallipadi@intel.com
|
a2bd920233 |
cpuidle: Do not use poll_idle unless user asks for it
poll_idle was added to CPUIDLE, just as a low latency idle handler, to be used in cases when user desires CPUs not to enter any idle state at all. It was supposed to be a run time idle=poll option to the user. But, it was indeed getting used during normal menu and ladder governor default case, with no special user setting (Reported by Linus Torvalds). Change below ensures that poll_idle will not be used unless user explicitly asks pm_qos infrastructure for zero latency requirement. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> |
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Mark Gross
|
d82b35186e |
pm qos infrastructure and interface
The following patch is a generalization of the latency.c implementation done
by Arjan last year. It provides infrastructure for more than one parameter,
and exposes a user mode interface for processes to register pm_qos
expectations of processes.
This interface provides a kernel and user mode interface for registering
performance expectations by drivers, subsystems and user space applications on
one of the parameters.
Currently we have {cpu_dma_latency, network_latency, network_throughput} as
the initial set of pm_qos parameters.
The infrastructure exposes multiple misc device nodes one per implemented
parameter. The set of parameters implement is defined by pm_qos_power_init()
and pm_qos_params.h. This is done because having the available parameters
being runtime configurable or changeable from a driver was seen as too easy to
abuse.
For each parameter a list of performance requirements is maintained along with
an aggregated target value. The aggregated target value is updated with
changes to the requirement list or elements of the list. Typically the
aggregated target value is simply the max or min of the requirement values
held in the parameter list elements.
>From kernel mode the use of this interface is simple:
pm_qos_add_requirement(param_id, name, target_value):
Will insert a named element in the list for that identified PM_QOS
parameter with the target value. Upon change to this list the new target is
recomputed and any registered notifiers are called only if the target value
is now different.
pm_qos_update_requirement(param_id, name, new_target_value):
Will search the list identified by the param_id for the named list element
and then update its target value, calling the notification tree if the
aggregated target is changed. with that name is already registered.
pm_qos_remove_requirement(param_id, name):
Will search the identified list for the named element and remove it, after
removal it will update the aggregate target and call the notification tree
if the target was changed as a result of removing the named requirement.
>From user mode:
Only processes can register a pm_qos requirement. To provide for
automatic cleanup for process the interface requires the process to register
its parameter requirements in the following way:
To register the default pm_qos target for the specific parameter, the
process must open one of /dev/[cpu_dma_latency, network_latency,
network_throughput]
As long as the device node is held open that process has a registered
requirement on the parameter. The name of the requirement is
"process_<PID>" derived from the current->pid from within the open system
call.
To change the requested target value the process needs to write a s32
value to the open device node. This translates to a
pm_qos_update_requirement call.
To remove the user mode request for a target value simply close the device
node.
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: fix build again]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: mark gross <mgross@linux.intel.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Adam Belay <abelay@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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Len Brown
|
4f86d3a8e2 |
cpuidle: consolidate 2.6.22 cpuidle branch into one patch
commit e5a16b1f9eec0af7cfa0830304b41c1c0833cf9f
Author: Len Brown <len.brown@intel.com>
Date: Tue Oct 2 23:44:44 2007 -0400
cpuidle: shrink diff
processor_idle.c | 440 +++++++++++++++++++++++++++++++++++++++++--
1 file changed, 429 insertions(+), 11 deletions(-)
Signed-off-by: Len Brown <len.brown@intel.com>
commit dfbb9d5aedfb18848a3e0d6f6e3e4969febb209c
Author: Len Brown <len.brown@intel.com>
Date: Wed Sep 26 02:17:55 2007 -0400
cpuidle: reduce diff size
Reduces the cpuidle processor_idle.c diff vs 2.6.22 from this
processor_idle.c | 2006 ++++++++++++++++++++++++++-----------------
1 file changed, 1219 insertions(+), 787 deletions(-)
to this:
processor_idle.c | 502 +++++++++++++++++++++++++++++++++++++++----
1 file changed, 458 insertions(+), 44 deletions(-)
...for the purpose of making the cpuilde patch less invasive
and easier to review.
no functional changes. build tested only.
Signed-off-by: Len Brown <len.brown@intel.com>
commit 889172fc915f5a7fe20f35b133cbd205ce69bf6c
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Thu Sep 13 13:40:05 2007 -0700
cpuidle: Retain old ACPI policy for !CONFIG_CPU_IDLE
Retain the old policy in processor_idle, so that when CPU_IDLE is not
configured, old C-state policy will still be used. This provides a
clean gradual migration path from old ACPI policy to new cpuidle
based policy.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 9544a8181edc7ecc33b3bfd69271571f98ed08bc
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Thu Sep 13 13:39:17 2007 -0700
cpuidle: Configure governors by default
Quoting Len "Do not give an option to users to shoot themselves in the foot".
Remove the configurability of ladder and menu governors as they are
needed for default policy of cpuidle. That way users will not be able to
have cpuidle without any policy loosing all C-state power savings.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 8975059a2c1e56cfe83d1bcf031bcf4cb39be743
Author: Adam Belay <abelay@novell.com>
Date: Tue Aug 21 18:27:07 2007 -0400
CPUIDLE: load ACPI properly when CPUIDLE is disabled
Change the registration return codes for when CPUIDLE
support is not compiled into the kernel. As a result, the ACPI
processor driver will load properly even if CPUIDLE is unavailable.
However, it may be possible to cleanup the ACPI processor driver further
and eliminate some dead code paths.
Signed-off-by: Adam Belay <abelay@novell.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit e0322e2b58dd1b12ec669bf84693efe0dc2414a8
Author: Adam Belay <abelay@novell.com>
Date: Tue Aug 21 18:26:06 2007 -0400
CPUIDLE: remove cpuidle_get_bm_activity()
Remove cpuidle_get_bm_activity() and updates governors
accordingly.
Signed-off-by: Adam Belay <abelay@novell.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 18a6e770d5c82ba26653e53d240caa617e09e9ab
Author: Adam Belay <abelay@novell.com>
Date: Tue Aug 21 18:25:58 2007 -0400
CPUIDLE: max_cstate fix
Currently max_cstate is limited to 0, resulting in no idle processor
power management on ACPI platforms. This patch restores the value to
the array size.
Signed-off-by: Adam Belay <abelay@novell.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 1fdc0887286179b40ce24bcdbde663172e205ef0
Author: Adam Belay <abelay@novell.com>
Date: Tue Aug 21 18:25:40 2007 -0400
CPUIDLE: handle BM detection inside the ACPI Processor driver
Update the ACPI processor driver to detect BM activity and
limit state entry depth internally, rather than exposing such
requirements to CPUIDLE. As a result, CPUIDLE can drop this
ACPI-specific interface and become more platform independent. BM
activity is now handled much more aggressively than it was in the
original implementation, so some testing coverage may be needed to
verify that this doesn't introduce any DMA buffer under-run issues.
Signed-off-by: Adam Belay <abelay@novell.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 0ef38840db666f48e3cdd2b769da676c57228dd9
Author: Adam Belay <abelay@novell.com>
Date: Tue Aug 21 18:25:14 2007 -0400
CPUIDLE: menu governor updates
Tweak the menu governor to more effectively handle non-timer
break events. Non-timer break events are detected by comparing the
actual sleep time to the expected sleep time. In future revisions, it
may be more reliable to use the timer data structures directly.
Signed-off-by: Adam Belay <abelay@novell.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit bb4d74fca63fa96cf3ace644b15ae0f12b7df5a1
Author: Adam Belay <abelay@novell.com>
Date: Tue Aug 21 18:24:40 2007 -0400
CPUIDLE: fix 'current_governor' sysfs entry
Allow the "current_governor" sysfs entry to properly handle
input terminated with '\n'.
Signed-off-by: Adam Belay <abelay@novell.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit df3c71559bb69b125f1a48971bf0d17f78bbdf47
Author: Len Brown <len.brown@intel.com>
Date: Sun Aug 12 02:00:45 2007 -0400
cpuidle: fix IA64 build (again)
Signed-off-by: Len Brown <len.brown@intel.com>
commit a02064579e3f9530fd31baae16b1fc46b5a7bca8
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Sun Aug 12 01:39:27 2007 -0400
cpuidle: Remove support for runtime changing of max_cstate
Remove support for runtime changeability of max_cstate. Drivers can use
use latency APIs.
max_cstate can still be used as a boot time option and dmi override.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 0912a44b13adf22f5e3f607d263aed23b4910d7e
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Sun Aug 12 01:39:16 2007 -0400
cpuidle: Remove ACPI cstate_limit calls from ipw2100
ipw2100 already has code to use accetable_latency interfaces to limit the
C-state. Remove the calls to acpi_set_cstate_limit and acpi_get_cstate_limit
as they are redundant.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit c649a76e76be6bff1fd770d0a775798813a3f6e0
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Sun Aug 12 01:35:39 2007 -0400
cpuidle: compile fix for pause and resume functions
Fix the compilation failure when cpuidle is not compiled in.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: Adam Belay <adam.belay@novell.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 2305a5920fb8ee6ccec1c62ade05aa8351091d71
Author: Adam Belay <abelay@novell.com>
Date: Thu Jul 19 00:49:00 2007 -0400
cpuidle: re-write
Some portions have been rewritten to make the code cleaner and lighter
weight. The following is a list of changes:
1.) the state name is now included in the sysfs interface
2.) detection, hotplug, and available state modifications are handled by
CPUIDLE drivers directly
3.) the CPUIDLE idle handler is only ever installed when at least one
cpuidle_device is enabled and ready
4.) the menu governor BM code no longer overflows
5.) the sysfs attributes are now printed as unsigned integers, avoiding
negative values
6.) a variety of other small cleanups
Also, Idle drivers are no longer swappable during runtime through the
CPUIDLE sysfs inteface. On i386 and x86_64 most idle handlers (e.g.
poll, mwait, halt, etc.) don't benefit from an infrastructure that
supports multiple states, so I think using a more general case idle
handler selection mechanism would be cleaner.
Signed-off-by: Adam Belay <abelay@novell.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit df25b6b56955714e6e24b574d88d1fd11f0c3ee5
Author: Len Brown <len.brown@intel.com>
Date: Tue Jul 24 17:08:21 2007 -0400
cpuidle: fix IA64 buid
Signed-off-by: Len Brown <len.brown@intel.com>
commit fd6ada4c14488755ff7068860078c437431fbccd
Author: Adrian Bunk <bunk@stusta.de>
Date: Mon Jul 9 11:33:13 2007 -0700
cpuidle: static
make cpuidle_replace_governor() static
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit c1d4a2cebcadf2429c0c72e1d29aa2a9684c32e0
Author: Adrian Bunk <bunk@stusta.de>
Date: Tue Jul 3 00:54:40 2007 -0400
cpuidle: static
This patch makes the needlessly global struct menu_governor static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit dbf8780c6e8d572c2c273da97ed1cca7608fd999
Author: Andrew Morton <akpm@linux-foundation.org>
Date: Tue Jul 3 00:49:14 2007 -0400
export symbol tick_nohz_get_sleep_length
ERROR: "tick_nohz_get_sleep_length" [drivers/cpuidle/governors/menu.ko] undefined!
ERROR: "tick_nohz_get_idle_jiffies" [drivers/cpuidle/governors/menu.ko] undefined!
And please be sure to get your changes to core kernel suitably reviewed.
Cc: Adam Belay <abelay@novell.com>
Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 29f0e248e7017be15f99febf9143a2cef00b2961
Author: Andrew Morton <akpm@linux-foundation.org>
Date: Tue Jul 3 00:43:04 2007 -0400
tick.h needs hrtimer.h
It uses hrtimers.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit e40cede7d63a029e92712a3fe02faee60cc38fb4
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Tue Jul 3 00:40:34 2007 -0400
cpuidle: first round of documentation updates
Documentation changes based on Pavel's feedback.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 83b42be2efece386976507555c29e7773a0dfcd1
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Tue Jul 3 00:39:25 2007 -0400
cpuidle: add rating to the governors and pick the one with highest rating by default
Introduce a governor rating scheme to pick the right governor by default.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit d2a74b8c5e8f22def4709330d4bfc4a29209b71c
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Tue Jul 3 00:38:08 2007 -0400
cpuidle: make cpuidle sysfs driver governor switch off by default
Make default cpuidle sysfs to show current_governor and current_driver in
read-only mode. More elaborate available_governors and available_drivers with
writeable current_governor and current_driver interface only appear with
"cpuidle_sysfs_switch" boot parameter.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 1f60a0e80bf83cf6b55c8845bbe5596ed8f6307b
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Tue Jul 3 00:37:00 2007 -0400
cpuidle: menu governor: change the early break condition
Change the C-state early break out algorithm in menu governor.
We only look at early breakouts that result in wakeups shorter than idle
state's target_residency. If such a breakout is frequent enough, eliminate
the particular idle state upto a timeout period.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 45a42095cf64b003b4a69be3ce7f434f97d7af51
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Tue Jul 3 00:35:38 2007 -0400
cpuidle: fix uninitialized variable in sysfs routine
Fix the uninitialized usage of ret.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 80dca7cdba3e6ee13eae277660873ab9584eb3be
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Tue Jul 3 00:34:16 2007 -0400
cpuidle: reenable /proc/acpi//power interface for the time being
Keep /proc/acpi/processor/CPU*/power around for a while as powertop depends
on it. It will be marked deprecated and removed in future. powertop can use
cpuidle interfaces instead.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 589c37c2646c5e3813a51255a5ee1159cb4c33fc
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Tue Jul 3 00:32:37 2007 -0400
cpuidle: menu governor and hrtimer compile fix
Compile fix for menu governor.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 0ba80bd9ab3ed304cb4f19b722e4cc6740588b5e
Author: Len Brown <len.brown@intel.com>
Date: Thu May 31 22:51:43 2007 -0400
cpuidle: build fix - cpuidle vs ipw2100 module
ERROR: "acpi_set_cstate_limit" [drivers/net/wireless/ipw2100.ko] undefined!
Signed-off-by: Len Brown <len.brown@intel.com>
commit d7d8fa7f96a7f7682be7c6cc0cc53fa7a18c3b58
Author: Adam Belay <abelay@novell.com>
Date: Sat Mar 24 03:47:07 2007 -0400
cpuidle: add the 'menu' governor
Here is my first take at implementing an idle PM governor that takes
full advantage of NO_HZ. I call it the 'menu' governor because it
considers the full list of idle states before each entry.
I've kept the implementation fairly simple. It attempts to guess the
next residency time and then chooses a state that would meet at least
the break-even point between power savings and entry cost. To this end,
it selects the deepest idle state that satisfies the following
constraints:
1. If the idle time elapsed since bus master activity was detected
is below a threshold (currently 20 ms), then limit the selection
to C2-type or above.
2. Do not choose a state with a break-even residency that exceeds
the expected time remaining until the next timer interrupt.
3. Do not choose a state with a break-even residency that exceeds
the elapsed time between the last pair of break events,
excluding timer interrupts.
This governor has an advantage over "ladder" governor because it
proactively checks how much time remains until the next timer interrupt
using the tick infrastructure. Also, it handles device interrupt
activity more intelligently by not including timer interrupts in break
event calculations. Finally, it doesn't make policy decisions using the
number of state entries, which can have variable residency times (NO_HZ
makes these potentially very large), and instead only considers sleep
time deltas.
The menu governor can be selected during runtime using the cpuidle sysfs
interface like so:
"echo "menu" > /sys/devices/system/cpu/cpuidle/current_governor"
Signed-off-by: Adam Belay <abelay@novell.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit a4bec7e65aa3b7488b879d971651cc99a6c410fe
Author: Adam Belay <abelay@novell.com>
Date: Sat Mar 24 03:47:03 2007 -0400
cpuidle: export time until next timer interrupt using NO_HZ
Expose information about the time remaining until the next
timer interrupt expires by utilizing the dynticks infrastructure.
Also modify the main idle loop to allow dynticks to handle
non-interrupt break events (e.g. DMA). Finally, expose sleep ticks
information to external code. Thomas Gleixner is responsible for much
of the code in this patch. However, I've made some additional changes,
so I'm probably responsible if there are any bugs or oversights :)
Signed-off-by: Adam Belay <abelay@novell.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 2929d8996fbc77f41a5ff86bb67cdde3ca7d2d72
Author: Adam Belay <abelay@novell.com>
Date: Sat Mar 24 03:46:58 2007 -0400
cpuidle: governor API changes
This patch prepares cpuidle for the menu governor. It adds an optional
stage after idle state entry to give the governor an opportunity to
check why the state was exited. Also it makes sure the idle loop
returns after each state entry, allowing the appropriate dynticks code
to run.
Signed-off-by: Adam Belay <abelay@novell.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 3a7fd42f9825c3b03e364ca59baa751bb350775f
Author: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Thu Apr 26 00:03:59 2007 -0700
cpuidle: hang fix
Prevent hang on x86-64, when ACPI processor driver is added as a module on
a system that does not support C-states.
x86-64 expects all idle handlers to enable interrupts before returning from
idle handler. This is due to enter_idle(), exit_idle() races. Make
cpuidle_idle_call() confirm to this when there is no pm_idle_old.
Also, cpuidle look at the return values of attch_driver() and set
current_driver to NULL if attach fails on all CPUs.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 4893339a142afbd5b7c01ffadfd53d14746e858e
Author: Shaohua Li <shaohua.li@intel.com>
Date: Thu Apr 26 10:40:09 2007 +0800
cpuidle: add support for max_cstate limit
With CPUIDLE framework, the max_cstate (to limit max cpu c-state)
parameter is ingored. Some systems require it to ignore C2/C3
and some drivers like ipw require it too.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 43bbbbe1cb998cbd2df656f55bb3bfe30f30e7d1
Author: Shaohua Li <shaohua.li@intel.com>
Date: Thu Apr 26 10:40:13 2007 +0800
cpuidle: add cpuidle_fore_redetect_devices API
add cpuidle_force_redetect_devices API,
which forces all CPU redetect idle states.
Next patch will use it.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit d1edadd608f24836def5ec483d2edccfb37b1d19
Author: Shaohua Li <shaohua.li@intel.com>
Date: Thu Apr 26 10:40:01 2007 +0800
cpuidle: fix sysfs related issue
Fix the cpuidle sysfs issue.
a. make kobject dynamicaly allocated
b. fixed sysfs init issue to avoid suspend/resume issue
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 7169a5cc0d67b263978859672e86c13c23a5570d
Author: Randy Dunlap <randy.dunlap@oracle.com>
Date: Wed Mar 28 22:52:53 2007 -0400
cpuidle: 1-bit field must be unsigned
A 1-bit bitfield has no room for a sign bit.
drivers/cpuidle/governors/ladder.c:54:16: error: dubious bitfield without explicit `signed' or `unsigned'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 4658620158dc2fbd9e4bcb213c5b6fb5d05ba7d4
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Wed Mar 28 22:52:41 2007 -0400
cpuidle: fix boot hang
Patch for cpuidle boot hang reported by Larry Finger here.
http://www.ussg.iu.edu/hypermail/linux/kernel/0703.2/2025.html
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Larry Finger <larry.finger@lwfinger.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit c17e168aa6e5fe3851baaae8df2fbc1cf11443a9
Author: Len Brown <len.brown@intel.com>
Date: Wed Mar 7 04:37:53 2007 -0500
cpuidle: ladder does not depend on ACPI
build fix for CONFIG_ACPI=n
In file included from drivers/cpuidle/governors/ladder.c:21:
include/acpi/processor.h:88: error: expected specifier-qualifier-list before âacpi_integerâ
include/acpi/processor.h:106: error: expected specifier-qualifier-list before âacpi_integerâ
include/acpi/processor.h:168: error: expected specifier-qualifier-list before âacpi_handleâ
Signed-off-by: Len Brown <len.brown@intel.com>
commit 8c91d958246bde68db0c3f0c57b535962ce861cb
Author: Adrian Bunk <bunk@stusta.de>
Date: Tue Mar 6 02:29:40 2007 -0800
cpuidle: make code static
This patch makes the following needlessly global code static:
- driver.c: __cpuidle_find_driver()
- governor.c: __cpuidle_find_governor()
- ladder.c: struct ladder_governor
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Adam Belay <abelay@novell.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 0c39dc3187094c72c33ab65a64d2017b21f372d2
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Wed Mar 7 02:38:22 2007 -0500
cpu_idle: fix build break
This patch fixes a build breakage with !CONFIG_HOTPLUG_CPU and
CONFIG_CPU_IDLE.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 8112e3b115659b07df340ef170515799c0105f82
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Tue Mar 6 02:29:39 2007 -0800
cpuidle: build fix for !CPU_IDLE
Fix the compile issues when CPU_IDLE is not configured.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Adam Belay <abelay@novell.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 1eb4431e9599cd25e0d9872f3c2c8986821839dd
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Thu Feb 22 13:54:57 2007 -0800
cpuidle take2: Basic documentation for cpuidle
Documentation for cpuidle infrastructure
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Adam Belay <abelay@novell.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit ef5f15a8b79123a047285ec2e3899108661df779
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Thu Feb 22 13:54:03 2007 -0800
cpuidle take2: Hookup ACPI C-states driver with cpuidle
Hookup ACPI C-states onto generic cpuidle infrastructure.
drivers/acpi/procesor_idle.c is now a ACPI C-states driver that registers as
a driver in cpuidle infrastructure and the policy part is removed from
drivers/acpi/processor_idle.c. We use governor in cpuidle instead.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Adam Belay <abelay@novell.com>
Signed-off-by: Len Brown <len.brown@intel.com>
commit 987196fa82d4db52c407e8c9d5dec884ba602183
Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Date: Thu Feb 22 13:52:57 2007 -0800
cpuidle take2: Core cpuidle infrastructure
Announcing 'cpuidle', a new CPU power management infrastructure to manage
idle CPUs in a clean and efficient manner.
cpuidle separates out the drivers that can provide support for multiple types
of idle states and policy governors that decide on what idle state to use
at run time.
A cpuidle driver can support multiple idle states based on parameters like
varying power consumption, wakeup latency, etc (ACPI C-states for example).
A cpuidle governor can be usage model specific (laptop, server,
laptop on battery etc).
Main advantage of the infrastructure being, it allows independent development
of drivers and governors and allows for better CPU power management.
A huge thanks to Adam Belay and Shaohua Li who were part of this mini-project
since its beginning and are greatly responsible for this patchset.
This patch:
Core cpuidle infrastructure.
Introduces a new abstraction layer for cpuidle:
* which manages drivers that can support multiple idles states. Drivers
can be generic or particular to specific hardware/platform
* allows pluging in multiple policy governors that can take idle state policy
decision
* The core also has a set of sysfs interfaces with which administrato can know
about supported drivers and governors and switch them at run time.
Signed-off-by: Adam Belay <abelay@novell.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
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