Commit Graph

480699 Commits

Author SHA1 Message Date
Krzysztof Kozlowski
d6cc1f5824 Documentation: charger: max14577: Document exported sysfs entry
Document the 'fast charge timer' setting exported by max14577 driver
through sysfs entry.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-09-24 15:25:56 +01:00
Krzysztof Kozlowski
8d70d68d7a devicetree: mfd: max14577: Add device tree bindings document
Add document describing device tree bindings for MAX14577 MFD
drivers: MFD core, extcon, regulator and charger.

Both MAX14577 and MAX77836 chipsets are documented.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-09-24 15:25:54 +01:00
Krzysztof Kozlowski
2c33e92962 power: max17040: Add ID for MAX77836 Fuel Gauge block
MAX77836 has the same Fuel Gauge as MAX17040/17048. The max17040 driver
can be safely re-used. The patch adds MAX77836 device to the array of
i2c_device_id. Additionally it removes the id associated with MAX17040
device as the value is not used.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-09-24 15:25:52 +01:00
Krzysztof Kozlowski
e30110e9c9 charger: max14577: Configure battery-dependent settings from DTS and sysfs
Remove hard-coded values for:
 - Fast Charge current,
 - End Of Charge current,
 - Fast Charge timer,
 - Overvoltage Protection Threshold,
 - Battery Constant Voltage,
and use DTS or sysfs to configure them. This allows using the max14577 charger
driver with different batteries.

Now the charger driver requires valid configuration data from DTS. In
case of wrong configuration data it fails during probe.

The fast charge timer is configured through sysfs entry.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-09-24 15:25:49 +01:00
Krzysztof Kozlowski
b8f139f68f regulator/mfd: max14577: Export symbols for calculating charger current
This patch prepares for changing the max14577 charger driver to allow
configuring battery-dependent settings from DTS.

The patch moves from regulator driver to MFD core driver and exports:
 - function for calculating register value for charger's current;
 - table of limits for chargers (MAX14577, MAX77836).

Previously they were used only by the max14577 regulator driver. In next
patch the charger driver will use them as well. Exporting them will
reduce unnecessary code duplication.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Mark Brown <broonie@linaro.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-09-24 15:25:47 +01:00
Krzysztof Kozlowski
3682a8ee87 charger: max14577: Add support for MAX77836 charger
Add support for MAX77836 charger to the max14577 driver. The MAX77836
charger is almost the same as 14577 model except:
 - No dead-battery detection;
 - Support for special charger (like in MAX77693);
 - Support for DX over-voltage protection (like in MAX77693);
 - Lower values of charging current (two times lower current for
   slow/fast charge, much lower EOC current);
 - Slightly different values in ChgTyp field of STATUS2 register. On
   MAX14577 0x6 is reserved and 0x7 dead battery. On the MAX77836 the
   0x6 means special charger and 0x7 is reserved. Regardless of these
   differences the driver maps them to one enum max14577_muic_charger_type.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-09-24 15:25:44 +01:00
Quentin Lambert
2f4096e311 PCI: Remove assignment from complicated "if" conditions
The modifications effectively change the value of len_tmp
in the case where the first condition is not met.

Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-09-24 07:56:43 -06:00
Quentin Lambert
79e50e7298 PCI: Remove assignment from "if" conditions
The following Coccinelle semantic patch was used to find and correct cases
of assignments in "if" conditions:

@@
expression var, expr;
statement S;
@@

+ var = expr;
  if(
- (var = expr)
+ var
  ) S

Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-09-24 07:50:53 -06:00
Quentin Lambert
656f978f9a PCI: Remove unnecessary curly braces
Remove curly braces in simple "if" cases.

No functional change.

Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-09-24 07:49:20 -06:00
Santosh Shilimkar
e0c524049f MAINTAINERS: Add Keystone Multicore Navigator drivers entry
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
2014-09-24 09:49:16 -04:00
Santosh Shilimkar
88139ed030 soc: ti: add Keystone Navigator DMA support
The Keystone Navigator DMA driver sets up the dma channels and flows for
the QMSS(Queue Manager SubSystem) who triggers the actual data movements
across clients using destination queues. Every client modules like
NETCP(Network Coprocessor), SRIO(Serial Rapid IO) and CRYPTO
Engines has its own instance of packet dma hardware. QMSS has also
an internal packet DMA module which is used as an infrastructure
DMA with zero copy.

Initially this driver was proposed as DMA engine driver but since the
hardware is not typical DMA engine and hence doesn't comply with typical
DMA engine driver needs, that approach was naked. Link to that
discussion -
	https://lkml.org/lkml/2014/3/18/340

As aligned, now we pair the Navigator DMA with its companion Navigator
QMSS subsystem driver.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sandeep Nair <sandeep_n@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
2014-09-24 09:49:15 -04:00
Santosh Shilimkar
8172296d87 Documentation: dt: soc: add Keystone Navigator DMA bindings
The Keystone Navigator DMA driver sets up the dma channels and flows for
the QMSS(Queue Manager SubSystem) who triggers the actual data movements
across clients using destination queues. Every client modules like
NETCP(Network Coprocessor), SRIO(Serial Rapid IO) and CRYPTO
Engines has its own instance of packet dma hardware. QMSS has also
an internal packet DMA module which is used as an infrastructure
DMA with zero copy.

Initially this driver was proposed as DMA engine driver but since the
hardware is not typical DMA engine and hence doesn't comply with typical
DMA engine driver needs, that approach was naked. Link to that
discussion -
	https://lkml.org/lkml/2014/3/18/340

As aligned, now we pair the Navigator DMA with its companion Navigator
QMSS subsystem driver.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sandeep Nair <sandeep_n@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
2014-09-24 09:49:15 -04:00
Sandeep Nair
41f93af900 soc: ti: add Keystone Navigator QMSS driver
The QMSS (Queue Manager Sub System) found on Keystone SOCs is one of
the main hardware sub system which forms the backbone of the Keystone
Multi-core Navigator. QMSS consist of queue managers, packed-data structure
processors(PDSP), linking RAM, descriptor pools and infrastructure
Packet DMA.

The Queue Manager is a hardware module that is responsible for accelerating
management of the packet queues. Packets are queued/de-queued by writing or
reading descriptor address to a particular memory mapped location. The PDSPs
perform QMSS related functions like accumulation, QoS, or event management.
Linking RAM registers are used to link the descriptors which are stored in
descriptor RAM. Descriptor RAM is configurable as internal or external memory.

The QMSS driver manages the PDSP setups, linking RAM regions,
queue pool management (allocation, push, pop and notify) and descriptor
pool management. The specifics on the device tree bindings for
QMSS can be found in:
	Documentation/devicetree/bindings/soc/keystone-navigator-qmss.txt

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sandeep Nair <sandeep_n@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
2014-09-24 09:49:14 -04:00
Sandeep Nair
a4dfb8c410 Documentation: dt: soc: add Keystone Navigator QMSS bindings
The QMSS (Queue Manager Sub System) found on Keystone SOCs is one of
the main hardware sub system which forms the backbone of the Keystone
Multi-core Navigator. QMSS consist of queue managers, packed-data structure
processors(PDSP), linking RAM, descriptor pools and infrastructure
Packet DMA.

The Queue Manager is a hardware module that is responsible for accelerating
management of the packet queues. Packets are queued/de-queued by writing or
reading descriptor address to a particular memory mapped location. The PDSPs
perform QMSS related functions like accumulation, QoS, or event management.
Linking RAM registers are used to link the descriptors which are stored in
descriptor RAM. Descriptor RAM is configurable as internal or external memory.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sandeep Nair <sandeep_n@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
2014-09-24 09:49:13 -04:00
Quentin Lambert
382a9c9adc PCI: Add space before open parenthesis
Add space before open parenthesis as is conventional.

No functional change.

[bhelgaas: fix a few more in ibmphp, shpchp]
Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-09-24 07:43:03 -06:00
Ben Hutchings
eeeda4cd06 x86/relocs: Make per_cpu_load_addr static
per_cpu_load_addr is only used for 64-bit relocations, but is
declared in both configurations of relocs.c - with different
types.  This has undefined behaviour in general.  GNU ld is
documented to use the larger size in this case, but other tools
may differ and some warn about this.

References: https://bugs.debian.org/748577
Reported-by: Michael Tautschnig <mt@debian.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: 748577@bugs.debian.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1411561812.3659.23.camel@decadent.org.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 15:17:47 +02:00
Oleg Nesterov
212be3b232 x86/lib/Makefile: Remove the unnecessary "+= thunk_64.o"
Trivial. We have "lib-y += thunk_$(BITS).o" at the start, no
need to add thunk_64.o if !CONFIG_X86_32.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921184232.GB23727@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 15:15:39 +02:00
Oleg Nesterov
0ad6e3c519 x86: Speed up ___preempt_schedule*() by using THUNK helpers
___preempt_schedule() does SAVE_ALL/RESTORE_ALL but this is
suboptimal, we do not need to save/restore the callee-saved
register. And we already have arch/x86/lib/thunk_*.S which
implements the similar asm wrappers, so it makes sense to
redefine ___preempt_schedule() as "THUNK ..." and remove
preempt.S altogether.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921184153.GA23727@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 15:15:38 +02:00
Mathias Krause
7da4b29d49 crypto: aesni - disable "by8" AVX CTR optimization
The "by8" implementation introduced in commit 22cddcc7df ("crypto: aes
- AES CTR x86_64 "by8" AVX optimization") is failing crypto tests as it
handles counter block overflows differently. It only accounts the right
most 32 bit as a counter -- not the whole block as all other
implementations do. This makes it fail the cryptomgr test #4 that
specifically tests this corner case.

As we're quite late in the release cycle, just disable the "by8" variant
for now.

Reported-by: Romain Francoise <romain@orebokech.com>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Chandramouli Narayanan <mouli@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-09-24 21:15:31 +08:00
Wanpeng Li
03bd4e1f72 sched: Fix unreleased llc_shared_mask bit during CPU hotplug
The following bug can be triggered by hot adding and removing a large number of
xen domain0's vcpus repeatedly:

	BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [..] find_busiest_group
	PGD 5a9d5067 PUD 13067 PMD 0
	Oops: 0000 [#3] SMP
	[...]
	Call Trace:
	load_balance
	? _raw_spin_unlock_irqrestore
	idle_balance
	__schedule
	schedule
	schedule_timeout
	? lock_timer_base
	schedule_timeout_uninterruptible
	msleep
	lock_device_hotplug_sysfs
	online_store
	dev_attr_store
	sysfs_write_file
	vfs_write
	SyS_write
	system_call_fastpath

Last level cache shared mask is built during CPU up and the
build_sched_domain() routine takes advantage of it to setup
the sched domain CPU topology.

However, llc_shared_mask is not released during CPU disable,
which leads to an invalid sched domainCPU topology.

This patch fix it by releasing the llc_shared_mask correctly
during CPU disable.

Yasuaki also reported that this can happen on real hardware:

  https://lkml.org/lkml/2014/7/22/1018

His case is here:

	==
	Here is an example on my system.
	My system has 4 sockets and each socket has 15 cores and HT is
	enabled. In this case, each core of sockes is numbered as
	follows:

		 | CPU#
	Socket#0 | 0-14 , 60-74
	Socket#1 | 15-29, 75-89
	Socket#2 | 30-44, 90-104
	Socket#3 | 45-59, 105-119

	Then llc_shared_mask of CPU#30 has 0x3fff80000001fffc0000000.

	It means that last level cache of Socket#2 is shared with
	CPU#30-44 and 90-104.

	When hot-removing socket#2 and #3, each core of sockets is
	numbered as follows:

		 | CPU#
	Socket#0 | 0-14 , 60-74
	Socket#1 | 15-29, 75-89

	But llc_shared_mask is not cleared. So llc_shared_mask of CPU#30
	remains having 0x3fff80000001fffc0000000.

	After that, when hot-adding socket#2 and #3, each core of
	sockets is numbered as follows:

		 | CPU#
	Socket#0 | 0-14 , 60-74
	Socket#1 | 15-29, 75-89
	Socket#2 | 30-59
	Socket#3 | 90-119

	Then llc_shared_mask of CPU#30 becomes
	0x3fff8000fffffffc0000000. It means that last level cache of
	Socket#2 is shared with CPU#30-59 and 90-104. So the mask has
	the wrong value.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Tested-by: Linn Crosetto <linn@hp.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1411547885-48165-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 15:13:20 +02:00
Minghuan Lian
24832b4de3 PCI: designware: Add get_msi_data() to pcie_host_ops
Add a struct pcie_host_ops .get_msi_data() method for platforms to return
their special MSI message data.

Signed-off-by: Minghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Mohit KUMAR <mohit.kumar@st.com>
2014-09-24 07:07:43 -06:00
Bryan O'Donoghue
ee1b5b165c x86/intel/quark: Switch off CR4.PGE so TLB flush uses CR3 instead
Quark x1000 advertises PGE via the standard CPUID method
PGE bits exist in Quark X1000's PTEs. In order to flush
an individual PTE it is necessary to reload CR3 irrespective
of the PTE.PGE bit.

See Quark Core_DevMan_001.pdf section 6.4.11

This bug was fixed in Galileo kernels, unfixed vanilla kernels are expected to
crash and burn on this platform.

Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: Borislav Petkov <bp@alien8.de>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1411514784-14885-1-git-send-email-pure.logic@nexus-software.ie
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 15:06:15 +02:00
Minghuan Lian
450e344e42 PCI: designware: Rename get_msi_data() to get_msi_addr()
The struct pcie_host_ops .get_msi_data() method returns the MSI message
address.  To accurately express its purpose, rename it to .get_msi_addr().

Signed-off-by: Minghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Mohit KUMAR <mohit.kumar@st.com>
2014-09-24 07:04:39 -06:00
Minghuan Lian
0c61ea77cc PCI: designware: Fix IO resource end address calculation
End address should be equal to start_addr + size - 1.  Fix PCI IO resource
end address calculation.

Signed-off-by: Minghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Mohit KUMAR <mohit.kumar@st.com>
2014-09-24 07:04:01 -06:00
Lan Tianyu
2ed53c0d6c x86/smpboot: Speed up suspend/resume by avoiding 100ms sleep for CPU offline during S3
With certain kernel configurations, CPU offline consumes more than
100ms during S3.

It's a timing related issue: native_cpu_die() would occasionally fall
into a 100ms sleep when the CPU idle loop thread marked the CPU state
to DEAD too slowly.

What native_cpu_die() does is that it polls the CPU state and waits
for 100ms if CPU state hasn't been marked to DEAD. The 100ms sleep
doesn't make sense and is purely historic.

To avoid such long sleeping, this patch adds a 'struct completion'
to each CPU, waits for the completion in native_cpu_die() and wakes
up the completion when the CPU state is marked to DEAD.

Tested on an Intel Xeon server with 48 cores, Ivybridge and on
Haswell laptops. The CPU offlining cost on these machines is
reduced from more than 100ms to less than 5ms. The system
suspend time is reduced by 2.3s on the servers.

Borislav and Prarit also helped to test the patch on an AMD
machine and a few systems of various sizes and configurations
(multi-socket, single-socket, no hyper threading, etc.). No
issues were seen.

Tested-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: srostedt@redhat.com
Cc: toshi.kani@hp.com
Cc: imammedo@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409039025-32310-1-git-send-email-tianyu.lan@intel.com
[ Improved a few minor details in the code, cleaned up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 15:02:06 +02:00
Minghuan Lian
ec98e9ab6f PCI: designware: Fix configuration base address when using 'reg'
The code has calculated cfg0_base and cfg1_base when parsing 'reg' or
'ranges' property of PCI DTS node, so remove duplicate calculation.  When
using 'reg', resource cfg is not used, so this code computed an incorrect
configuration base.

Signed-off-by: Minghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Mohit KUMAR <mohit.kumar@st.com>
2014-09-24 07:01:47 -06:00
Stephane Eranian
521e8bac67 perf/x86/intel/uncore: Update support for client uncore IMC PMU
This patch restructures the memory controller (IMC) uncore PMU support
for client SNB/IVB/HSW processors. The main change is that it can now
cope with more than one PCI device ID per processor model. There are
many flavors of memory controllers for each processor. They have
different PCI device ID, yet they behave the same w.r.t. the memory
controller PMU that we are interested in.

The patch now supports two distinct memory controllers for IVB
processors: one for mobile, one for desktop.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140917090616.GA11281@quad
Cc: ak@linux.intel.com
Cc: kan.liang@intel.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:25 +02:00
Andi Kleen
b10fc1c3e3 perf/x86/intel/uncore: Fix PCU filter setup for Sandy/Ivy/Haswell EP
The PCU frequency band filters use 8 bit each in a register.
When setting up the value the shift value was not correctly
scaled, which resulted in all filters except for band 0 to
be zero. Fix the scaling.

This allows to correctly monitor multiple uncore frequency bands.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1409872109-31645-5-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:24 +02:00
Andi Kleen
7e96ae1a89 perf/x86/intel/uncore: Add missing cbox filter flags on IvyBridge-EP uncore driver
The IvyBridge-EP uncore driver was missing three filter flags:
NC, ISOC, C6 which are useful in some cases. Support them in the same way
as the Haswell EP driver, by allowing to set them and exposing
them in the sysfs formats.

Also fix a typo in a define.

Relies on the Haswell EP driver to be applied earlier.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1409872109-31645-4-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:23 +02:00
Yan, Zheng
513d793e5f perf/x86/intel/uncore: Register the PMU only if the uncore pci device exists
Current code registers PMUs for all possible uncore pci devices.
This is not good because, on some machines, one or more uncore pci
devices can be missing. The missing pci device make corresponding
PMU unusable. Register the PMU only if the uncore device exists.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1409872109-31645-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:22 +02:00
Yan, Zheng
e735b9db12 perf/x86/intel/uncore: Add Haswell-EP uncore support
The uncore subsystem in Haswell-EP is similar to Sandy/Ivy
Bridge-EP. There are some differences in config register
encoding and pci device IDs. The Haswell-EP uncore also
supports a few new events. Add the Haswell-EP driver to
the snbep split driver.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
[ Add missing break. Add imc events. Add cbox nc/isoc/c6. ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1409872109-31645-2-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:21 +02:00
Andi Kleen
fdda3c4aac perf/x86/intel: Use Broadwell cache event list for Haswell
Use the newly added Broadwell cache event list for Haswell too.
All Haswell and Broadwell events and offcore masks used in these lists
are identical.

However Haswell is very different from the Sandy Bridge
list that was used previously. That fixes a wide range of mis-counting
cache events.

The node events are now only for retired memory events, so prefetching
and speculative memory accesses are not included. They are PEBS
capable now, which makes it much easier to sample for them, plus it's
possible to create address maps with -d.

The prefetch events are gone now. They way the hardware counts
them is very misleading (some prefetches included, others not), so
it seemed best to leave them out.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1409683455-29168-5-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:20 +02:00
Andi Kleen
c46e665f03 perf/x86: Add INST_RETIRED.ALL workarounds
On Broadwell INST_RETIRED.ALL cannot be used with any period
that doesn't have the lowest 6 bits cleared. And the period
should not be smaller than 128.

Add a new callback to enforce this, and set it for Broadwell.

This is erratum BDM57 and BDM11.

How does this handle the case when an app requests a specific
period with some of the bottom bits set

The apps thinks it is sampling at X occurences per sample, when it is
in fact at X - 63 (worst case).

Short answer:

Any useful instruction sampling period needs to be 4-6 orders
of magnitude larger than 128, as an PMI every 128 instructions
would instantly overwhelm the system and be throttled.
So the +-64 error from this is really small compared to the
period, much smaller than normal system jitter.

Long answer:

<write up by Peter:>

IFF we guarantee perf_event_attr::sample_period >= 128.

Suppose we start out with sample_period=192; then we'll set period_left
to 192, we'll end up with left = 128 (we truncate the lower bits). We
get an interrupt, find that period_left = 64 (>0 so we return 0 and
don't get an overflow handler), up that to 128. Then we trigger again,
at n=256. Then we find period_left = -64 (<=0 so we return 1 and do get
an overflow). We increment with sample_period so we get left = 128. We
fire again, at n=384, period_left = 0 (<=0 so we return 1 and get an
overflow). And on and on.

So while the individual interrupts are 'wrong' we get then with
interval=256,128 in exactly the right ratio to average out at 192. And
this works for everything >=128.

So the num_samples*fixed_period thing is still entirely correct +- 127,
which is good enough I'd say, as you already have that error anyhow.

So no need to 'fix' the tools, al we need to do is refuse to create
INST_RETIRED:ALL events with sample_period < 128.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Mark Davies <junk@eslaf.co.uk>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1409683455-29168-4-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:19 +02:00
Andi Kleen
86a349a28b perf/x86/intel: Add Broadwell core support
Add Broadwell support for Broadwell Client to perf.  This is very
similar to Haswell.  It uses a new cache event table, because there
were various changes there.

The constraint list has one new event that needs to be handled over
Haswell.

The PEBS event list is the same, so we reuse Haswell's.

[fengguang.wu: make intel_bdw_event_constraints[] static]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1409683455-29168-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:18 +02:00
Andi Kleen
d86c8eaf95 perf/x86/intel: Document all Haswell models
Add names for each Haswell model as requested by Peter.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1409683455-29168-2-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:16 +02:00
Andi Kleen
b76146851e perf/x86/intel: Remove incorrect model number from Haswell perf
71 is a Broadwell, not a Haswell. The model number was added
by mistake earlier.

Remove it for now, until it can be re-added later with
real Broadwell support.

In practice it does not cause a lot of issues because the Broadwell
PMU is very similar to Haswell, but some details were wrong,
and it's better to handle it correctly.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: http://lkml.kernel.org/r/1409683455-29168-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:15 +02:00
Jiri Olsa
802c8a61d4 Revert "perf: Do not allow optimized switch for non-cloned events"
This reverts commit 1f9a7268c6.

With the fix of the initial state for the cloned event we now correctly
handle the error described in:

  1f9a7268c6 perf: Do not allow optimized switch for non-cloned events

so we can revert it.

I made an automated test for this, but its not suitable for automated
perf tests framework. It needs to be customized for each machine (the
more cpu the higher numbers for GROUPS/WORKERS/BYTES) and it could take
longer time to hit the issue.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140910143535.GD2409@krava.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:13 +02:00
Jiri Olsa
1929def9e6 perf: Fix child event initial state setup
Currently we initialize the child event based on the original
parent state. This is wrong, because the original parent event
(and its state) is not related to current fork and also could
be already gone.

We need to initialize the child state based on the immediate
parent event state.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410520708-19275-2-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:12 +02:00
Jiri Olsa
dc633982ff perf: Do not POLLHUP event if it has children
Currently we return POLLHUP in event polling if the monitored
process is done, but we didn't consider possible children,
that might be still running and producing data.

Before returning POLLHUP making sure that:

   1) the monitored task has exited and that
   2) we don't have any children to monitor

Also adding parent wakeup when the child event is gone.

Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410520708-19275-1-git-send-email-jolsa@kernel.org
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:48:11 +02:00
Dave Hansen
cebf15eb09 x86, sched: Add new topology for multi-NUMA-node CPUs
I'm getting the spew below when booting with Haswell (Xeon
E5-2699 v3) CPUs and the "Cluster-on-Die" (CoD) feature enabled
in the BIOS.  It seems similar to the issue that some folks from
AMD ran in to on their systems and addressed in this commit:

  161270fc1f ("x86/smp: Fix topology checks on AMD MCM CPUs")

Both these Intel and AMD systems break an assumption which is
being enforced by topology_sane(): a socket may not contain more
than one NUMA node.

AMD special-cased their system by looking for a cpuid flag.  The
Intel mode is dependent on BIOS options and I do not know of a
way which it is enumerated other than the tables being parsed
during the CPU bringup process.  In other words, we have to trust
the ACPI tables <shudder>.

This detects the situation where a NUMA node occurs at a place in
the middle of the "CPU" sched domains.  It replaces the default
topology with one that relies on the NUMA information from the
firmware (SRAT table) for all levels of sched domains above the
hyperthreads.

This also fixes a sysfs bug.  We used to freak out when we saw
the "mc" group cross a node boundary, so we stopped building the
MC group.  MC gets exported as the 'core_siblings_list' in
/sys/devices/system/cpu/cpu*/topology/ and this caused CPUs with
the same 'physical_package_id' to not be listed together in
'core_siblings_list'.  This violates a statement from
Documentation/ABI/testing/sysfs-devices-system-cpu:

	core_siblings: internal kernel map of cpu#'s hardware threads
	within the same physical_package_id.

	core_siblings_list: human-readable list of the logical CPU
	numbers within the same physical_package_id as cpu#.

The sysfs effects here cause an issue with the hwloc tool where
it gets confused and thinks there are more sockets than are
physically present.

Before this patch, there are two packages:

# cd /sys/devices/system/cpu/
# cat cpu*/topology/physical_package_id | sort | uniq -c
     18 0
     18 1

But 4 _sets_ of core siblings:

# cat cpu*/topology/core_siblings_list | sort | uniq -c
      9 0-8
      9 18-26
      9 27-35
      9 9-17

After this set, there are only 2 sets of core siblings, which
is what we expect for a 2-socket system.

# cat cpu*/topology/physical_package_id | sort | uniq -c
     18 0
     18 1
# cat cpu*/topology/core_siblings_list | sort | uniq -c
     18 0-17
     18 18-35

Example spew:
...
	NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter.
	 #2  #3  #4  #5  #6  #7  #8
	.... node  #1, CPUs:    #9
	------------[ cut here ]------------
	WARNING: CPU: 9 PID: 0 at /home/ak/hle/linux-hle-2.6/arch/x86/kernel/smpboot.c:306 topology_sane.isra.2+0x74/0x90()
	sched: CPU #9's mc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency.
	Modules linked in:
	CPU: 9 PID: 0 Comm: swapper/9 Not tainted 3.17.0-rc1-00293-g8e01c4d-dirty #631
	Hardware name: Intel Corporation S2600WTT/S2600WTT, BIOS GRNDSDP1.86B.0036.R05.1407140519 07/14/2014
	0000000000000009 ffff88046ddabe00 ffffffff8172e485 ffff88046ddabe48
	ffff88046ddabe38 ffffffff8109691d 000000000000b001 0000000000000009
	ffff88086fc12580 000000000000b020 0000000000000009 ffff88046ddabe98
	Call Trace:
	[<ffffffff8172e485>] dump_stack+0x45/0x56
	[<ffffffff8109691d>] warn_slowpath_common+0x7d/0xa0
	[<ffffffff8109698c>] warn_slowpath_fmt+0x4c/0x50
	[<ffffffff81074f94>] topology_sane.isra.2+0x74/0x90
	[<ffffffff8107530e>] set_cpu_sibling_map+0x31e/0x4f0
	[<ffffffff8107568d>] start_secondary+0x1ad/0x240
	---[ end trace 3fe5f587a9fcde61 ]---
	#10 #11 #12 #13 #14 #15 #16 #17
	.... node  #2, CPUs:   #18 #19 #20 #21 #22 #23 #24 #25 #26
	.... node  #3, CPUs:   #27 #28 #29 #30 #31 #32 #33 #34 #35

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
[ Added LLC domain and s/match_mc/match_die/ ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: brice.goglin@gmail.com
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/20140918193334.C065EBCE@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:14 +02:00
Kirill Tkhai
8aa6f0ebf4 sched/rt: Use resched_curr() in task_tick_rt()
Some time ago PREEMPT_NEED_RESCHED was implemented,
so reschedule technics is a little more difficult now.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183642.11015.66039.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:12 +02:00
Kirill Tkhai
f1e3a0932f sched: Use rq->rd in sched_setaffinity() under RCU read lock
Probability of use-after-free isn't zero in this place.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183636.11015.83611.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:11 +02:00
Kirill Tkhai
16303ab2fe sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask'
Nothing is locked there, so label's name only confuses a reader.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140922183630.11015.59500.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:10 +02:00
Kirill Tkhai
66339c31bc sched: Use dl_bw_of() under RCU read lock
dl_bw_of() dereferences rq->rd which has to have RCU read lock held.
Probability of use-after-free isn't zero here.

Also add lockdep assert into dl_bw_cpus().

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183624.11015.71558.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:09 +02:00
Kirill Tkhai
7a96c231ca sched/fair: Remove duplicate code from can_migrate_task()
Combine two branches which do the same.

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183612.11015.64200.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:07 +02:00
Peter Zijlstra
c55f5158f5 sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW
Kirill found that there's a subtle race in the
__ARCH_WANT_UNLOCKED_CTXSW code, and instead of fixing it, remove the
entire exception because neither arch that uses it seems to actually
still require it.

Boot tested on mips64el (qemu) only.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kirill Tkhai <tkhai@yandex.ru>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: oleg@redhat.com
Cc: linux@roeck-us.net
Cc: linux-ia64@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/20140923150641.GH3312@worktop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:05 +02:00
Oleg Nesterov
5bd96ab6fe sched: print_rq(): Don't use tasklist_lock
read_lock_irqsave(tasklist_lock) in print_rq() looks strange. We do
not need to disable irqs, and they are already disabled by the caller.

And afaics this lock buys nothing, we can rely on rcu_read_lock().
In this case it makes sense to also move rcu_read_lock/unlock from
the caller to print_rq().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921193341.GA28628@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:04 +02:00
Oleg Nesterov
3472eaa1f1 sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock()
1. read_lock(tasklist_lock) does not need to disable irqs.

2. ->mm != NULL is a common mistake, use PF_KTHREAD.

3. The second ->mm check can be simply removed.

4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) +
   __task_rq_lock().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921193338.GA28621@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:03 +02:00
Oleg Nesterov
8651c65844 sched: Fix the task-group check in tg_has_rt_tasks()
tg_has_rt_tasks() wants to find an RT task in this task_group, but
task_rq(p)->rt.tg wrongly checks the root rt_rq.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Link: http://lkml.kernel.org/r/20140921193336.GA28618@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:47:00 +02:00
Nicolas Pitre
83a0a96a5f sched/fair: Leverage the idle state info when choosing the "idlest" cpu
The code in find_idlest_cpu() looks for the CPU with the smallest load.
However, if multiple CPUs are idle, the first idle CPU is selected
irrespective of the depth of its idle state.

Among the idle CPUs we should pick the one with with the shallowest idle
state, or the latest to have gone idle if all idle CPUs are in the same
state.  The later applies even when cpuidle is configured out.

This patch doesn't cover the following issues:

- The idle exit latency of a CPU might be larger than the time needed
  to migrate the waking task to an already running CPU with sufficient
  capacity, and therefore performance would benefit from task packing
  in such case (in most cases task packing is about power saving).

- Some idle states have a non negligible and non abortable entry latency
  which needs to run to completion before the exit latency can start.
  A concurrent patch series is making this info available to the cpuidle
  core.  Once available, the entry latency with the idle timestamp could
  determine when the exit latency may be effective.

Those issues will be handled in due course.  In the mean time, what
is implemented here should improve things already compared to the current
state of affairs.

Based on an initial patch from Daniel Lezcano.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-pm@vger.kernel.org
Cc: linaro-kernel@lists.linaro.org
Link: http://lkml.kernel.org/n/tip-@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-24 14:46:59 +02:00