17 Dec, 2014

1 commit

  • When the ladder governor sees the CPUIDLE_FLAG_TIME_INVALID flag,
    it unconditionally causes a state promotion by setting last_residency
    to a number higher than the state's promotion_time:

    last_residency = last_state->threshold.promotion_time + 1

    It does this for fear that cpuidle_get_last_residency()
    will be in-accurate, because cpuidle_enter_state() invoked
    a state with CPUIDLE_FLAG_TIME_INVALID.

    But the only state with CPUIDLE_FLAG_TIME_INVALID is
    acpi_safe_halt(), which may return well after its actual
    idle duration because it enables interrupts, so cpuidle_enter_state()
    also measures interrupt service time.

    So what? In ladder, a huge invalid last_residency has exactly
    the same effect as the current code -- it unconditionally
    causes a state promotion.

    In the case where the idle residency plus measured interrupt
    handling time is less than the state's demotion_time -- we should
    use that timestamp to give ladder a chance to demote, rather than
    unconditionally promoting.

    This can be done by simply ignoring the CPUIDLE_FLAG_TIME_INVALID,
    and using the "invalid" time, as it is either equal to what we are
    doing today, or better.

    Signed-off-by: Len Brown
    Acked-by: Daniel Lezcano
    Signed-off-by: Rafael J. Wysocki

    Len Brown
     

13 Nov, 2014

1 commit

  • The only place where the time is invalid is when the ACPI_CSTATE_FFH entry
    method is not set. Otherwise for all the drivers, the time can be correctly
    measured.

    Instead of duplicating the CPUIDLE_FLAG_TIME_VALID flag in all the drivers
    for all the states, just invert the logic by replacing it by the flag
    CPUIDLE_FLAG_TIME_INVALID, hence we can set this flag only for the acpi idle
    driver, remove the former flag from all the drivers and invert the logic with
    this flag in the different governor.

    Signed-off-by: Daniel Lezcano
    Signed-off-by: Rafael J. Wysocki

    Daniel Lezcano
     

27 Aug, 2014

1 commit


29 Jul, 2014

1 commit


15 Jul, 2013

1 commit

  • cpufreq governors are defined as modules in the code, but the Kconfig
    options do not allow them to be built as modules. This is not really
    a problem, but the cpuidle init ordering is: the cpuidle init
    functions (framework and driver) and then the governors. That leads
    to some weirdness in the cpuidle framework.

    Namely, cpuidle_register_device() calls cpuidle_enable_device() which
    fails at the first attempt, because governors have not been registered
    yet. When a governor is registered, the framework calls
    cpuidle_enable_device() again which runs __cpuidle_register_device()
    only then. Of course, for that to work, the cpuidle_enable_device()
    return value has to be ignored by cpuidle_register_device().

    Instead of having this cyclic call graph and relying on a positive
    side effects of the hackish back and forth cpuidle_enable_device()
    calls it is better to fix the cpuidle init ordering.

    To that end, replace the module init code with postcore_initcall()
    so we have:

    * cpuidle framework : core_initcall
    * cpuidle governors : postcore_initcall
    * cpuidle drivers : device_initcall

    and remove the corresponding module exit code as it is dead anyway
    (governors can't be built as modules).

    [rjw: Changelog]
    Signed-off-by: Daniel Lezcano
    Signed-off-by: Rafael J. Wysocki

    Daniel Lezcano
     

04 Sep, 2012

2 commits

  • For the mechanism introduced by commit cbc9ef0 (PM / Domains: Add
    preliminary support for cpuidle, v2) to work with the ladder
    governor, that governor should respect the "disabled" state flag
    added by that commit. Change the ladder governor accordingly.

    Signed-off-by: Rafael J. Wysocki

    Rafael J. Wysocki
     
  • There are two cpuidle governors ladder and menu. While the ladder
    governor is always available, if CONFIG_CPU_IDLE is selected, the
    menu governor additionally requires CONFIG_NO_HZ.

    A particular C state can be disabled by writing to the sysfs file
    /sys/devices/system/cpu/cpuN/cpuidle/stateN/disable, but this mechanism
    is only implemented in the menu governor. Thus, in a system where
    CONFIG_NO_HZ is not selected, the ladder governor becomes default and
    always will walk through all sleep states - irrespective of whether the
    C state was disabled via sysfs or not. The only way to select a specific
    C state was to write the related latency to /dev/cpu_dma_latency and
    keep the file open as long as this setting was required - not very
    practical and not suitable for setting a single core in an SMP system.

    With this patch, the ladder governor only will promote to the next
    C state, if it has not been disabled, and it will demote, if the
    current C state was disabled.

    Note that the patch does not make the setting of the sysfs variable
    "disable" coherent, i.e. if one is disabling a light state, then all
    deeper states are disabled as well, but the "disable" variable does not
    reflect it. Likewise, if one enables a deep state but a lighter state
    still is disabled, then this has no effect. A related section has been
    added to the documentation.

    Signed-off-by: Carsten Emde
    Signed-off-by: Rafael J. Wysocki

    Carsten Emde
     

08 Nov, 2011

1 commit

  • * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
    cpuidle: Single/Global registration of idle states
    cpuidle: Split cpuidle_state structure and move per-cpu statistics fields
    cpuidle: Remove CPUIDLE_FLAG_IGNORE and dev->prepare()
    cpuidle: Move dev->last_residency update to driver enter routine; remove dev->last_state
    ACPI: Fix CONFIG_ACPI_DOCK=n compiler warning
    ACPI: Export FADT pm_profile integer value to userspace
    thermal: Prevent polling from happening during system suspend
    ACPI: Drop ACPI_NO_HARDWARE_INIT
    ACPI atomicio: Convert width in bits to bytes in __acpi_ioremap_fast()
    PNPACPI: Simplify disabled resource registration
    ACPI: Fix possible recursive locking in hwregs.c
    ACPI: use kstrdup()
    mrst pmu: update comment
    tools/power turbostat: less verbose debugging

    Linus Torvalds
     

07 Nov, 2011

2 commits

  • This patch makes the cpuidle_states structure global (single copy)
    instead of per-cpu. The statistics needed on per-cpu basis
    by the governor are kept per-cpu. This simplifies the cpuidle
    subsystem as state registration is done by single cpu only.
    Having single copy of cpuidle_states saves memory. Rare case
    of asymmetric C-states can be handled within the cpuidle driver
    and architectures such as POWER do not have asymmetric C-states.

    Having single/global registration of all the idle states,
    dynamic C-state transitions on x86 are handled by
    the boot cpu. Here, the boot cpu would disable all the devices,
    re-populate the states and later enable all the devices,
    irrespective of the cpu that would receive the notification first.

    Reference:
    https://lkml.org/lkml/2011/4/25/83

    Signed-off-by: Deepthi Dharwar
    Signed-off-by: Trinabh Gupta
    Tested-by: Jean Pihet
    Reviewed-by: Kevin Hilman
    Acked-by: Arjan van de Ven
    Acked-by: Kevin Hilman
    Signed-off-by: Len Brown

    Deepthi Dharwar
     
  • Cpuidle governor only suggests the state to enter using the
    governor->select() interface, but allows the low level driver to
    override the recommended state. The actual entered state
    may be different because of software or hardware demotion. Software
    demotion is done by the back-end cpuidle driver and can be accounted
    correctly. Current cpuidle code uses last_state field to capture the
    actual state entered and based on that updates the statistics for the
    state entered.

    Ideally the driver enter routine should update the counters,
    and it should return the state actually entered rather than the time
    spent there. The generic cpuidle code should simply handle where
    the counters live in the sysfs namespace, not updating the counters.

    Reference:
    https://lkml.org/lkml/2011/3/25/52

    Signed-off-by: Deepthi Dharwar
    Signed-off-by: Trinabh Gupta
    Tested-by: Jean Pihet
    Reviewed-by: Kevin Hilman
    Acked-by: Arjan van de Ven
    Acked-by: Kevin Hilman
    Signed-off-by: Len Brown

    Deepthi Dharwar
     

01 Nov, 2011

1 commit


25 Aug, 2011

1 commit


11 May, 2010

1 commit

  • This patch changes the string based list management to a handle base
    implementation to help with the hot path use of pm-qos, it also renames
    much of the API to use "request" as opposed to "requirement" that was
    used in the initial implementation. I did this because request more
    accurately represents what it actually does.

    Also, I added a string based ABI for users wanting to use a string
    interface. So if the user writes 0xDDDDDDDD formatted hex it will be
    accepted by the interface. (someone asked me for it and I don't think
    it hurts anything.)

    This patch updates some documentation input I got from Randy.

    Signed-off-by: markgross
    Signed-off-by: Rafael J. Wysocki

    Mark Gross
     

16 Dec, 2009

1 commit

  • It does not seem possible that ldev can be NULL, so drop the unnecessary
    test. If ldev can somehow be NULL, then the initialization of last_idx
    should be moved below the test.

    A simplified version of the semantic match that detects this problem is as
    follows (http://coccinelle.lip6.fr/):

    //
    @match exists@
    expression x, E;
    identifier fld;
    @@

    * x->fld
    ... when != \(x = E\|&x\)
    * x == NULL
    //

    Signed-off-by: Julia Lawall
    Acked-by: Arjan van de Ven
    Cc: Ingo Molnar
    Cc: Venkatesh Pallipadi
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Julia Lawall
     

16 Aug, 2008

2 commits

  • ladder governor only honored latency requirement when promoting C-states.
    Instead. it should check for latency requirement on each idle call,
    and demote to appropriate C-state when there is a latency requirement change.

    Signed-off-by: Venkatesh Pallipadi
    Signed-off-by: Andi Kleen

    venkatesh.pallipadi@intel.com
     
  • 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
    Signed-off-by: Andi Kleen

    venkatesh.pallipadi@intel.com
     

06 Feb, 2008

1 commit

  • 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_" 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
    Cc: "John W. Linville"
    Cc: Len Brown
    Cc: Jaroslav Kysela
    Cc: Takashi Iwai
    Cc: Arjan van de Ven
    Cc: Venki Pallipadi
    Cc: Adam Belay
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mark Gross
     

10 Oct, 2007

1 commit

  • commit e5a16b1f9eec0af7cfa0830304b41c1c0833cf9f
    Author: Len Brown
    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

    commit dfbb9d5aedfb18848a3e0d6f6e3e4969febb209c
    Author: Len Brown
    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

    commit 889172fc915f5a7fe20f35b133cbd205ce69bf6c
    Author: Venki Pallipadi
    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
    Signed-off-by: Len Brown

    commit 9544a8181edc7ecc33b3bfd69271571f98ed08bc
    Author: Venki Pallipadi
    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
    Signed-off-by: Len Brown

    commit 8975059a2c1e56cfe83d1bcf031bcf4cb39be743
    Author: Adam Belay
    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
    Acked-by: Venkatesh Pallipadi
    Signed-off-by: Len Brown

    commit e0322e2b58dd1b12ec669bf84693efe0dc2414a8
    Author: Adam Belay
    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
    Acked-by: Venkatesh Pallipadi
    Signed-off-by: Len Brown

    commit 18a6e770d5c82ba26653e53d240caa617e09e9ab
    Author: Adam Belay
    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
    Acked-by: Venkatesh Pallipadi
    Signed-off-by: Len Brown

    commit 1fdc0887286179b40ce24bcdbde663172e205ef0
    Author: Adam Belay
    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
    Acked-by: Venkatesh Pallipadi
    Signed-off-by: Len Brown

    commit 0ef38840db666f48e3cdd2b769da676c57228dd9
    Author: Adam Belay
    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
    Acked-by: Venkatesh Pallipadi
    Signed-off-by: Len Brown

    commit bb4d74fca63fa96cf3ace644b15ae0f12b7df5a1
    Author: Adam Belay
    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
    Acked-by: Venkatesh Pallipadi
    Signed-off-by: Len Brown

    commit df3c71559bb69b125f1a48971bf0d17f78bbdf47
    Author: Len Brown
    Date: Sun Aug 12 02:00:45 2007 -0400

    cpuidle: fix IA64 build (again)

    Signed-off-by: Len Brown

    commit a02064579e3f9530fd31baae16b1fc46b5a7bca8
    Author: Venkatesh Pallipadi
    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
    Signed-off-by: Len Brown

    commit 0912a44b13adf22f5e3f607d263aed23b4910d7e
    Author: Venkatesh Pallipadi
    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
    Signed-off-by: Len Brown

    commit c649a76e76be6bff1fd770d0a775798813a3f6e0
    Author: Venkatesh Pallipadi
    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
    Acked-by: Adam Belay
    Signed-off-by: Len Brown

    commit 2305a5920fb8ee6ccec1c62ade05aa8351091d71
    Author: Adam Belay
    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
    Acked-by: Venkatesh Pallipadi
    Acked-by: Shaohua Li
    Signed-off-by: Len Brown

    commit df25b6b56955714e6e24b574d88d1fd11f0c3ee5
    Author: Len Brown
    Date: Tue Jul 24 17:08:21 2007 -0400

    cpuidle: fix IA64 buid

    Signed-off-by: Len Brown

    commit fd6ada4c14488755ff7068860078c437431fbccd
    Author: Adrian Bunk
    Date: Mon Jul 9 11:33:13 2007 -0700

    cpuidle: static

    make cpuidle_replace_governor() static

    Signed-off-by: Adrian Bunk
    Cc: Venkatesh Pallipadi
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit c1d4a2cebcadf2429c0c72e1d29aa2a9684c32e0
    Author: Adrian Bunk
    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
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit dbf8780c6e8d572c2c273da97ed1cca7608fd999
    Author: Andrew Morton
    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
    Cc: Venki Pallipadi
    Cc: Ingo Molnar
    Cc: Thomas Gleixner
    Cc: john stultz
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 29f0e248e7017be15f99febf9143a2cef00b2961
    Author: Andrew Morton
    Date: Tue Jul 3 00:43:04 2007 -0400

    tick.h needs hrtimer.h

    It uses hrtimers.

    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit e40cede7d63a029e92712a3fe02faee60cc38fb4
    Author: Venki Pallipadi
    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
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 83b42be2efece386976507555c29e7773a0dfcd1
    Author: Venki Pallipadi
    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
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit d2a74b8c5e8f22def4709330d4bfc4a29209b71c
    Author: Venki Pallipadi
    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
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 1f60a0e80bf83cf6b55c8845bbe5596ed8f6307b
    Author: Venki Pallipadi
    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
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 45a42095cf64b003b4a69be3ce7f434f97d7af51
    Author: Venki Pallipadi
    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
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 80dca7cdba3e6ee13eae277660873ab9584eb3be
    Author: Venki Pallipadi
    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
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 589c37c2646c5e3813a51255a5ee1159cb4c33fc
    Author: Venki Pallipadi
    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
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 0ba80bd9ab3ed304cb4f19b722e4cc6740588b5e
    Author: Len Brown
    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

    commit d7d8fa7f96a7f7682be7c6cc0cc53fa7a18c3b58
    Author: Adam Belay
    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
    Signed-off-by: Len Brown

    commit a4bec7e65aa3b7488b879d971651cc99a6c410fe
    Author: Adam Belay
    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
    Signed-off-by: Len Brown

    commit 2929d8996fbc77f41a5ff86bb67cdde3ca7d2d72
    Author: Adam Belay
    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
    Signed-off-by: Len Brown

    commit 3a7fd42f9825c3b03e364ca59baa751bb350775f
    Author: Venki Pallipadi
    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
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 4893339a142afbd5b7c01ffadfd53d14746e858e
    Author: Shaohua Li
    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
    Signed-off-by: Len Brown

    commit 43bbbbe1cb998cbd2df656f55bb3bfe30f30e7d1
    Author: Shaohua Li
    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
    Signed-off-by: Len Brown

    commit d1edadd608f24836def5ec483d2edccfb37b1d19
    Author: Shaohua Li
    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
    Signed-off-by: Len Brown

    commit 7169a5cc0d67b263978859672e86c13c23a5570d
    Author: Randy Dunlap
    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
    Cc: Venkatesh Pallipadi
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 4658620158dc2fbd9e4bcb213c5b6fb5d05ba7d4
    Author: Venkatesh Pallipadi
    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
    Cc: Larry Finger
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit c17e168aa6e5fe3851baaae8df2fbc1cf11443a9
    Author: Len Brown
    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 ‘acpi_integer’
    include/acpi/processor.h:106: error: expected specifier-qualifier-list before ‘acpi_integer’
    include/acpi/processor.h:168: error: expected specifier-qualifier-list before ‘acpi_handle’

    Signed-off-by: Len Brown

    commit 8c91d958246bde68db0c3f0c57b535962ce861cb
    Author: Adrian Bunk
    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
    Cc: Venkatesh Pallipadi
    Cc: Adam Belay
    Cc: Shaohua Li
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 0c39dc3187094c72c33ab65a64d2017b21f372d2
    Author: Venkatesh Pallipadi
    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
    Signed-off-by: Adrian Bunk
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 8112e3b115659b07df340ef170515799c0105f82
    Author: Venkatesh Pallipadi
    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
    Cc: Adam Belay
    Cc: Shaohua Li
    Signed-off-by: Andrew Morton
    Signed-off-by: Len Brown

    commit 1eb4431e9599cd25e0d9872f3c2c8986821839dd
    Author: Venkatesh Pallipadi
    Date: Thu Feb 22 13:54:57 2007 -0800

    cpuidle take2: Basic documentation for cpuidle

    Documentation for cpuidle infrastructure

    Signed-off-by: Venkatesh Pallipadi
    Signed-off-by: Adam Belay
    Signed-off-by: Shaohua Li
    Signed-off-by: Len Brown

    commit ef5f15a8b79123a047285ec2e3899108661df779
    Author: Venkatesh Pallipadi
    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
    Signed-off-by: Venkatesh Pallipadi
    Signed-off-by: Adam Belay
    Signed-off-by: Len Brown

    commit 987196fa82d4db52c407e8c9d5dec884ba602183
    Author: Venkatesh Pallipadi
    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
    Signed-off-by: Shaohua Li
    Signed-off-by: Venkatesh Pallipadi
    Signed-off-by: Len Brown

    Signed-off-by: Len Brown

    Len Brown