Currently we use overlap to weaken the SYNC hint, but allow it to
set the hint as well.

 echo NO_SYNC_WAKEUP > /debug/sched_features
 echo SYNC_MORE > /debug/sched_features

preserves pipe-test behaviour without using the WF_SYNC hint.

Worth playing with on more workloads...
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The sync argument rename to introduce WF_* broke stuff by missing a
local alias for an argument in __wake_up_common, fix it by using
the more descriptive wake_flags name.

This restores WF_SYNC propagation, which fixes wake_affine()
behaviour, which fixes pipe-test.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Avoid the cache buddies from biasing the time distribution away
from fork()ers. Normally the next buddy will be the preferred
scheduling target, but this makes fork()s prefer to run the new
child, whereas we prefer to run the parent, since that will
generate more work.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In order to extend the functions to have more than 1 flag (sync),
rename the argument to flags, and explicitly define a WF_ space for
individual flags.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In order to be able to rename the sync argument, we need to rename
the current flag argument.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

I suspect a feed-back loop between cpuidle and the aperf/mperf
cpu_power bits, where when we have idle C-states lower the ratio,
which leads to lower cpu_power and then less load, which generates
more idle time, etc..

Put in a knob to disable it.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

APERF/MPERF support for cpu_power.

APERF/MPERF is arch defined to be a relative scale of work capacity
per logical cpu, this is assumed to include SMT and Turbo mode.

APERF/MPERF are specified to both reset to 0 when either counter
wraps, which is highly inconvenient, since that'll give a blimp
when that happens. The manual specifies writing 0 to the counters
after each read, but that's 1) too expensive, and 2) destroys the
possibility of sharing these counters with other users, so we live
with the blimp - the other existing user does too.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Move some of the aperf/mperf code out from the cpufreq driver
thingy so that other people can enjoy it too.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: cpufreq@vger.kernel.org
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Move the APERFMPERF capacility into a X86_FEATURE flag so that it
can be used outside of the acpi cpufreq driver.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: cpufreq@vger.kernel.org
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Provide an ach specific hook for cpufreq based scaling of
cpu_power.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
[ego@in.ibm.com: spotting bugs]
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

If we're looking to place a new task, we might as well find the
idlest position _now_, not 1 tick ago.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Make the idle balancer more agressive, to improve a
x264 encoding workload provided by Jason Garrett-Glaser:

 NEXT_BUDDY NO_LB_BIAS
 encoded 600 frames, 252.82 fps, 22096.60 kb/s
 encoded 600 frames, 250.69 fps, 22096.60 kb/s
 encoded 600 frames, 245.76 fps, 22096.60 kb/s

 NO_NEXT_BUDDY LB_BIAS
 encoded 600 frames, 344.44 fps, 22096.60 kb/s
 encoded 600 frames, 346.66 fps, 22096.60 kb/s
 encoded 600 frames, 352.59 fps, 22096.60 kb/s

 NO_NEXT_BUDDY NO_LB_BIAS
 encoded 600 frames, 425.75 fps, 22096.60 kb/s
 encoded 600 frames, 425.45 fps, 22096.60 kb/s
 encoded 600 frames, 422.49 fps, 22096.60 kb/s

Peter pointed out that this is better done via newidle_idx,
not via LB_BIAS, newidle balancing should look for where
there is load _now_, not where there was load 2 ticks ago.

Worst-case latencies are improved as well as no buddies
means less vruntime spread. (as per prior lkml discussions)

This change improves kbuild-peak parallelism as well.
Reported-by: NJason Garrett-Glaser <darkshikari@gmail.com>
Signed-off-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1253011667.9128.16.camel@marge.simson.net>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

CPU level should have WAKE_AFFINE, whereas ALLNODES is dubious.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When merging select_task_rq_fair() and sched_balance_self() we lost
the use of wake_idx, restore that and set them to 0 to make wake
balancing more aggressive.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

While merging select_task_rq_fair() and sched_balance_self() I made
a mistake that leads to testing the wrong task affinty.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

for_each_domain() uses RCU to serialize the sched_domains, except
it doesn't actually use rcu_read_lock() and instead relies on
disabling preemption -> FAIL.

XXX: audit other sched_domain code.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

One of the problems of power-saving balancing is that under certain
scenarios it is too slow and allows tons of real work to pile up.

Avoid this by ignoring the powersave stuff when there's real work
to be done.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The problem with wake_idle() is that is doesn't respect things like
cpu_power, which means it doesn't deal well with SMT nor the recent
RT interaction.

To cure this, it needs to do what sched_balance_self() does, which
leads to the possibility of merging select_task_rq_fair() and
sched_balance_self().

Modify sched_balance_self() to:

  - update_shares() when walking up the domain tree,
    (it only called it for the top domain, but it should
     have done this anyway), which allows us to remove
    this ugly bit from try_to_wake_up().

  - do wake_affine() on the smallest domain that contains
    both this (the waking) and the prev (the wakee) cpu for
    WAKE invocations.

Then use the top-down balance steps it had to replace wake_idle().

This leads to the dissapearance of SD_WAKE_BALANCE and
SD_WAKE_IDLE_FAR, with SD_WAKE_IDLE replaced with SD_BALANCE_WAKE.

SD_WAKE_AFFINE needs SD_BALANCE_WAKE to be effective.

Touch all topology bits to replace the old with new SD flags --
platforms might need re-tuning, enabling SD_BALANCE_WAKE
conditionally on a NUMA distance seems like a good additional
feature, magny-core and small nehalem systems would want this
enabled, systems with slow interconnects would not.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We're going to want to drop rq->lock in try_to_wake_up() for a
longer period of time, however we also want to deal with concurrent
waking of the same task, which is currently handled by holding
rq->lock.

So introduce a new TASK state, namely TASK_WAKING, which indicates
someone is already waking the task (other wakers will fail p->state
& state).

We also keep preemption disabled over the whole ttwu().
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Rather ugly patch to fully place the sched_balance_self() code
inside the fair class.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Move the sched_balance_self() code into sched_fair.c

This facilitates the merger of sched_balance_self() and
sched_fair::select_task_rq().
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In preparation to other code movement, move weighted_cpuload(),
source_load() and target_load() before the class includes.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add text...
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add a NEXT_BUDDY feature flag to aid in debugging.
Signed-off-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

It consists of two conditions, split them out in separate toggles
so we can test them independently.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Merge branch 'x86-setup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-setup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, e820: Guard against array overflowed in __e820_add_region()
  x86, setup: remove obsolete pre-Kconfig CONFIG_VIDEO_ variables

Merge branch 'x86-percpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-percpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, percpu: Collect hot percpu variables into one cacheline
  x86, percpu: Fix DECLARE/DEFINE_PER_CPU_PAGE_ALIGNED()
  x86, percpu: Add 'percpu_read_stable()' interface for cacheable accesses

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, highmem_32.c: Clean up comment
  x86, pgtable.h: Clean up types
  x86: Clean up dump_pagetable()

Merge branch 'x86-kbuild-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-kbuild-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Simplify the Makefile in a minor way through use of cc-ifversion

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86-64: move clts into batch cpu state updates when preloading fpu
  x86-64: move unlazy_fpu() into lazy cpu state part of context switch
  x86-32: make sure clts is batched during context switch
  x86: split out core __math_state_restore

Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Decrease the level of some NUMA messages to KERN_DEBUG

* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (22 commits)
  x86: Fix code patching for paravirt-alternatives on 486
  x86, msr: change msr-reg.o to obj-y, and export its symbols
  x86: Use hard_smp_processor_id() to get apic id for AMD K8 cpus
  x86, sched: Workaround broken sched domain creation for AMD Magny-Cours
  x86, mcheck: Use correct cpumask for shared bank4
  x86, cacheinfo: Fixup L3 cache information for AMD multi-node processors
  x86: Fix CPU llc_shared_map information for AMD Magny-Cours
  x86, msr: Fix msr-reg.S compilation with gas 2.16.1, on 32-bit too
  x86: Move kernel_fpu_using to irq_fpu_usable in asm/i387.h
  x86, msr: fix msr-reg.S compilation with gas 2.16.1
  x86, msr: Export the register-setting MSR functions via /dev/*/msr
  x86, msr: Create _on_cpu helpers for {rw,wr}msr_safe_regs()
  x86, msr: Have the _safe MSR functions return -EIO, not -EFAULT
  x86, msr: CFI annotations, cleanups for msr-reg.S
  x86, asm: Make _ASM_EXTABLE() usable from assembly code
  x86, asm: Add 32-bit versions of the combined CFI macros
  x86, AMD: Disable wrongly set X86_FEATURE_LAHF_LM CPUID bit
  x86, msr: Rewrite AMD rd/wrmsr variants
  x86, msr: Add rd/wrmsr interfaces with preset registers
  x86: add specific support for Intel Atom architecture
  ...

Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Make memtype_seq_ops const
  x86: uv: Clean up uv_ptc_init(), use proc_create()
  x86: Use printk_once()
  x86/cpu: Clean up various files a bit
  x86: Remove duplicated #include
  x86, ipi: Clean up safe_smp_processor_id() by using the cpu_has_apic() macro helper
  x86: Clean up idt_descr and idt_tableby using NR_VECTORS instead of hardcoded number
  x86: Further clean up of mtrr/generic.c
  x86: Clean up mtrr/main.c
  x86: Clean up mtrr/state.c
  x86: Clean up mtrr/mtrr.h
  x86: Clean up mtrr/if.c
  x86: Clean up mtrr/generic.c
  x86: Clean up mtrr/cyrix.c
  x86: Clean up mtrr/cleanup.c
  x86: Clean up mtrr/centaur.c
  x86: Clean up mtrr/amd.c:
  x86: ds.c fix invalid assignment

Merge branch 'x86-asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-asm-generic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: remove all now-duplicate header files
  x86: convert termios.h to the asm-generic version
  x86: convert almost generic headers to asm-generic version
  x86: convert trivial headers to asm-generic version
  x86: add copies of some headers to convert to asm-generic

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86/i386: Put aligned stack-canary in percpu shared_aligned section
  x86/i386: Make sure stack-protector segment base is cache aligned
  x86: Detect stack protector for i386 builds on x86_64
  x86: allow "=rm" in native_save_fl()
  x86: properly annotate alternatives.c
  x86: Introduce GDT_ENTRY_INIT(), initialize bad_bios_desc statically
  x86, 32-bit: Use generic sys_pipe()
  x86: Introduce GDT_ENTRY_INIT(), fix APM
  x86: Introduce GDT_ENTRY_INIT()
  x86: Introduce set_desc_base() and set_desc_limit()
  x86: Remove unused patch_espfix_desc()
  x86: Use get_desc_base()

Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits)
  ACPI, x86: expose some IO-APIC routines when CONFIG_ACPI=n
  x86, apic: Slim down stack usage in early_init_lapic_mapping()
  x86, ioapic: Get rid of needless check and simplify ioapic_setup_resources()
  x86, ioapic: Define IO_APIC_DEFAULT_PHYS_BASE constant
  x86: Fix x86_model test in es7000_apic_is_cluster()
  x86, apic: Move dmar_table_init() out of enable_IR()
  x86, ioapic: Panic on irq-pin binding only if needed
  x86/apic: Enable x2APIC without interrupt remapping under KVM
  x86, apic: Drop redundant bit assignment
  x86, ioapic: Throw BUG instead of NULL dereference
  x86, ioapic: Introduce for_each_irq_pin() helper
  x86: Remove superfluous NULL pointer check in destroy_irq()
  x86/ioapic.c: unify ioapic_retrigger_irq()
  x86/ioapic.c: convert __target_IO_APIC_irq to conventional for() loop
  x86/ioapic.c: clean up replace_pin_at_irq_node logic and comments
  x86/ioapic.c: convert replace_pin_at_irq_node to conventional for() loop
  x86/ioapic.c: simplify add_pin_to_irq_node()
  x86/ioapic.c: convert io_apic_level_ack_pending loop to normal for() loop
  x86/ioapic.c: move lost comment to what seems like appropriate place
  x86/ioapic.c: remove redundant declaration of irq_pin_list
  ...

* git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (87 commits)
  NFSv4: Disallow 'mount -t nfs4 -overs=2' and 'mount -t nfs4 -overs=3'
  NFS: Allow the "nfs" file system type to support NFSv4
  NFS: Move details of nfs4_get_sb() to a helper
  NFS: Refactor NFSv4 text-based mount option validation
  NFS: Mount option parser should detect missing "port="
  NFS: out of date comment regarding O_EXCL above nfs3_proc_create()
  NFS: Handle a zero-length auth flavor list
  SUNRPC: Ensure that sunrpc gets initialised before nfs, lockd, etc...
  nfs: fix compile error in rpc_pipefs.h
  nfs: Remove reference to generic_osync_inode from a comment
  SUNRPC: cache must take a reference to the cache detail's module on open()
  NFS: Use the DNS resolver in the mount code.
  NFS: Add a dns resolver for use with NFSv4 referrals and migration
  SUNRPC: Fix a typo in cache_pipefs_files
  nfs: nfs4xdr: optimize low level decoding
  nfs: nfs4xdr: get rid of READ_BUF
  nfs: nfs4xdr: simplify decode_exchange_id by reusing decode_opaque_inline
  nfs: nfs4xdr: get rid of COPYMEM
  nfs: nfs4xdr: introduce decode_sessionid helper
  nfs: nfs4xdr: introduce decode_verifier helper
  ...

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev: (25 commits)
  pata_rz1000: use printk_once
  ahci: kill @force_restart and refine CLO for ahci_kick_engine()
  pata_cs5535: add pci id for AMD based CS5535 controllers
  ahci: Add AMD SB900 SATA/IDE controller device IDs
  drivers/ata: use resource_size
  sata_fsl: Defer non-ncq commands when ncq commands active
  libata: add SATA PMP revision information for spec 1.2
  libata: fix off-by-one error in ata_tf_read_block()
  ahci: Gigabyte GA-MA69VM-S2 can't do 64bit DMA
  ahci: make ahci_asus_m2a_vm_32bit_only() quirk more generic
  dmi: extend dmi_get_year() to dmi_get_date()
  dmi: fix date handling in dmi_get_year()
  libata: unbreak TPM filtering by reorganizing ata_scsi_pass_thru()
  sata_sis: convert to slave_link
  sata_sil24: always set protocol override for non-ATAPI data commands
  libata: Export AHCI capabilities
  libata: Delegate nonrot flag setting to SCSI
  [libata] Add pata_rdc driver for RDC ATA devices
  drivers/ata: Remove unnecessary semicolons
  libata: remove spindown skipping and warning
  ...

Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (105 commits)
  ring-buffer: only enable ring_buffer_swap_cpu when needed
  ring-buffer: check for swapped buffers in start of committing
  tracing: report error in trace if we fail to swap latency buffer
  tracing: add trace_array_printk for internal tracers to use
  tracing: pass around ring buffer instead of tracer
  tracing: make tracing_reset safe for external use
  tracing: use timestamp to determine start of latency traces
  tracing: Remove mentioning of legacy latency_trace file from documentation
  tracing/filters: Defer pred allocation, fix memory leak
  tracing: remove users of tracing_reset
  tracing: disable buffers and synchronize_sched before resetting
  tracing: disable update max tracer while reading trace
  tracing: print out start and stop in latency traces
  ring-buffer: disable all cpu buffers when one finds a problem
  ring-buffer: do not count discarded events
  ring-buffer: remove ring_buffer_event_discard
  ring-buffer: fix ring_buffer_read crossing pages
  ring-buffer: remove unnecessary cpu_relax
  ring-buffer: do not swap buffers during a commit
  ring-buffer: do not reset while in a commit
  ...