* pm-sleep:
PM: hibernate: constify attribute_group structures.
PM / hibernate: Drop redundant parameter of swsusp_alloc()
PM / hibernate: Use CONFIG_HAVE_SET_MEMORY for include condition
x86/power/64: Use char arrays for asm function names
* pm-cpufreq:
cpufreq / CPPC: Initialize policy->min to lowest nonlinear performance
cpufreq: sfi: make freq_table static
cpufreq: exynos5440: Fix inconsistent indenting
cpufreq: imx6q: imx6ull should use the same flow as imx6ul
cpufreq: dt: Add support for hi3660
* intel_pstate:
cpufreq: Update scaling_cur_freq documentation
cpufreq: intel_pstate: Clean up after performance governor changes
intel_pstate: skip scheduler hook when in "performance" mode
intel_pstate: delete scheduler hook in HWP mode
x86: use common aperfmperf_khz_on_cpu() to calculate KHz using APERF/MPERF
cpufreq: intel_pstate: Remove max/min fractions to limit performance
x86: do not use cpufreq_quick_get() for /proc/cpuinfo "cpu MHz"
* pm-cpuidle:
cpuidle: menu: allow state 0 to be disabled
intel_idle: Use more common logging style
x86/ACPI/cstate: Allow ACPI C1 FFH MWAIT use on AMD systems
ARM: cpuidle: Support asymmetric idle definition
* pm-tools:
cpupower: Add support for new AMD family 0x17
cpupower: Fix bug where return value was not used
tools/power turbostat: update version number
tools/power turbostat: decode MSR_IA32_MISC_ENABLE only on Intel
tools/power turbostat: stop migrating, unless '-m'
tools/power turbostat: if --debug, print sampling overhead
tools/power turbostat: hide SKL counters, when not requested
intel_pstate: use updated msr-index.h HWP.EPP values
tools/power x86_energy_perf_policy: support HWP.EPP
x86: msr-index.h: fix shifts to ULL results in HWP macros.
x86: msr-index.h: define HWP.EPP values
x86: msr-index.h: define EPB mid-points
Commit f8475cef90 "x86: use common aperfmperf_khz_on_cpu() to
calculate KHz using APERF/MPERF" modified the way the scaling_cur_freq
cpufreq policy attribute in sysfs is handled on contemporary
Intel-based x86 systems, so update the documentation to reflect
that change.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After commit 82b4e03e01 (intel_pstate: skip scheduler hook when in
"performance" mode) get_target_pstate_use_performance() and
get_target_pstate_use_cpu_load() are never called if scaling_governor
is "performance", so drop the CPUFREQ_POLICY_PERFORMANCE checks from
them as they will never trigger anyway.
Moreover, the documentation needs to be updated to reflect the change
made by the above commit, so do that too.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group. So mark the non-const structs as const.
File size before:
text data bss dec hex filename
6332 488 308 7128 1bd8 kernel/power/hibernate.o
File size After adding 'const':
text data bss dec hex filename
6396 424 308 7128 1bd8 kernel/power/hibernate.o
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The menu driver does not allow state0 to be disabled completely.
If it is disabled but other enabled states don't meet latency
requirements, it is still used.
Fix this by starting with the first enabled idle state. Fall back
to state 0 if no idle states are enabled (arguably this should be
-EINVAL if it is attempted, but this is the minimal fix).
Acked-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Remove #define PREFIX and add #define pr_fmt to use more common logging.
Miscellanea:
o Add missing newline to format
o Convert a single printk without KERN_<LEVEL> to pr_info
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Description of Lowest Perfomance in ACPI 6.1 specification states:
"Lowest Performance is the absolute lowest performance level of
the platform. Selecting a performance level lower than the lowest
nonlinear performance level may actually cause an efficiency penalty,
but should reduce the instantaneous power consumption of the processor.
In traditional terms, this represents the T-state range of performance
levels."
Set the default value of policy->min to Lowest Nonlinear Performance
to avoid any potential efficiency penalty.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Alexey Klimov <alexey.klimov@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The first parameter of swsusp_alloc is not used, so drop it.
Signed-off-by: BaoJun Luo <baojun.luo@samsung.com>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Kbuild reported a build failure when CONFIG_STRICT_KERNEL_RWX was
enabled on powerpc. We don't yet have ARCH_HAS_SET_MEMORY and ppc32
saw a build failure.
I've only done a basic compile test with a config that has
hibernation enabled.
Fixes: 50327ddfbc (kernel/power/snapshot.c: use set_memory.h header)
Reported-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
AMD systems support the Monitor/Mwait instructions and these can be used
for ACPI C1 in the same way as on Intel systems.
Three things are needed:
1) This patch.
2) BIOS that declares a C1 state in _CST to use FFH, with correct values.
3) CPUID_Fn00000005_EDX is non-zero on the system.
The BIOS on AMD systems have historically not defined a C1 state in _CST,
so the acpi_idle driver uses HALT for ACPI C1.
Currently released systems have CPUID_Fn00000005_EDX as reserved/RAZ. If a
BIOS is released for these systems that requests a C1 state with FFH, the
FFH implementation in Linux will fail since CPUID_Fn00000005_EDX is 0. The
acpi_idle driver will then fallback to using HALT for ACPI C1.
Future systems are expected to have non-zero CPUID_Fn00000005_EDX and BIOS
support for using FFH for ACPI C1.
Allow ffh_cstate_init() to succeed on AMD systems.
Tested on Fam15h and Fam17h systems.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When the governor is set to "performance", intel_pstate does not
need the scheduler hook for doing any calculations. Under these
conditions, its only purpose is to continue to maintain
cpufreq/scaling_cur_freq.
The cpufreq/scaling_cur_freq sysfs attribute is now provided by
shared x86 cpufreq code on modern x86 systems, including
all systems supported by the intel_pstate driver.
So in "performance" governor mode, the scheduler hook can be skipped.
This applies to both in Software and Hardware P-state control modes.
Suggested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The cpufreq/scaling_cur_freq sysfs attribute is now provided by
shared x86 cpufreq code on modern x86 systems, including
all systems supported by the intel_pstate driver.
In HWP mode, maintaining that value was the sole purpose of
the scheduler hook, intel_pstate_update_util_hwp(),
so it can now be removed.
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The goal of this change is to give users a uniform and meaningful
result when they read /sys/...cpufreq/scaling_cur_freq
on modern x86 hardware, as compared to what they get today.
Modern x86 processors include the hardware needed
to accurately calculate frequency over an interval --
APERF, MPERF, and the TSC.
Here we provide an x86 routine to make this calculation
on supported hardware, and use it in preference to any
driver driver-specific cpufreq_driver.get() routine.
MHz is computed like so:
MHz = base_MHz * delta_APERF / delta_MPERF
MHz is the average frequency of the busy processor
over a measurement interval. The interval is
defined to be the time between successive invocations
of aperfmperf_khz_on_cpu(), which are expected to to
happen on-demand when users read sysfs attribute
cpufreq/scaling_cur_freq.
As with previous methods of calculating MHz,
idle time is excluded.
base_MHz above is from TSC calibration global "cpu_khz".
This x86 native method to calculate MHz returns a meaningful result
no matter if P-states are controlled by hardware or firmware
and/or if the Linux cpufreq sub-system is or is-not installed.
When this routine is invoked more frequently, the measurement
interval becomes shorter. However, the code limits re-computation
to 10ms intervals so that average frequency remains meaningful.
Discerning users are encouraged to take advantage of
the turbostat(8) utility, which can gracefully handle
concurrent measurement intervals of arbitrary length.
Signed-off-by: Len Brown <len.brown@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add support for new AMD family 0x17
- Add bit field changes to the msr_pstate structure
- Add the new formula for the calculation of cof
- Changed method to access to CpbDis
Signed-off-by: Sherry Hurwitz <sherry.hurwitz@amd.com>
Acked-by: Thomas Renninger <trenn@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Save return value from amd_pci_get_num_boost_states
and remove redundant setting of *support
Signed-off-by: Sherry Hurwitz <sherry.hurwitz@amd.com>
Reviewed-by: Thomas Renninger <trenn@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull turbostat fixes from Len Brown.
* 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
tools/power turbostat: update version number
tools/power turbostat: decode MSR_IA32_MISC_ENABLE only on Intel
tools/power turbostat: stop migrating, unless '-m'
tools/power turbostat: if --debug, print sampling overhead
tools/power turbostat: hide SKL counters, when not requested
Pull x86 fix from Thomas Gleixner:
"A single fix to unbreak the vdso32 build for 64bit kernels caused by
excess #includes in the mshyperv header"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mshyperv: Remove excess #includes from mshyperv.h
Pull timer fixes from Thomas Gleixner:
"A few fixes for timekeeping and timers:
- Plug a subtle race due to a missing READ_ONCE() in the timekeeping
code where reloading of a pointer results in an inconsistent
callback argument being supplied to the clocksource->read function.
- Correct the CLOCK_MONOTONIC_RAW sub-nanosecond accounting in the
time keeping core code, to prevent a possible discontuity.
- Apply a similar fix to the arm64 vdso clock_gettime()
implementation
- Add missing includes to clocksource drivers, which relied on
indirect includes which fails in certain configs.
- Use the proper iomem pointer for read/iounmap in a probe function"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
arm64/vdso: Fix nsec handling for CLOCK_MONOTONIC_RAW
time: Fix CLOCK_MONOTONIC_RAW sub-nanosecond accounting
time: Fix clock->read(clock) race around clocksource changes
clocksource: Explicitly include linux/clocksource.h when needed
clocksource/drivers/arm_arch_timer: Fix read and iounmap of incorrect variable
Pull perf fixes from Thomas Gleixner:
"Three fixlets for perf:
- Return the proper error code if aux buffers for a event are not
supported.
- Calculate the probe offset for inlined functions correctly
- Update the Skylake DTLB load/store miss event so it can count 1G
TLB entries as well"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf probe: Fix probe definition for inlined functions
perf/x86/intel: Add 1G DTLB load/store miss support for SKL
perf/aux: Correct return code of rb_alloc_aux() if !has_aux(ev)
Pull irq fix from Thomas Gleixner:
"A single fix for the MIPS GIC to prevent ftrace recursion"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/mips-gic: Mark count and compare accessors notrace
Pull input fixes from Dmitry Torokhov:
- a quirk to i8042 to ignore timeout bit on Lifebook AH544
- a fixup to Synaptics RMI function 54 that was breaking some Dells
- a fix for memory leak in soc_button_array driver
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: synaptics-rmi4 - only read the F54 query registers which are used
Input: i8042 - add Fujitsu Lifebook AH544 to notimeout list
Input: soc_button_array - fix leaking the ACPI button descriptor buffer
Pull SCSI target fixes from Nicholas Bellinger:
"Here are the target-pending fixes for v4.12-rc7 that have been queued
up for the last 2 weeks. This includes:
- Fix a TMR related kref underflow detected by the recent refcount_t
conversion in upstream.
- Fix a iscsi-target corner case during explicit connection logout
timeout failure.
- Address last fallout in iscsi-target immediate data handling from
v4.4 target-core now allowing control CDB payload underflow"
* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
iscsi-target: Reject immediate data underflow larger than SCSI transfer length
iscsi-target: Fix delayed logout processing greater than SECONDS_FOR_LOGOUT_COMP
target: Fix kref->refcount underflow in transport_cmd_finish_abort
Turbostat has the capability to set its own affinity to
each CPU so that its MSR accesses are on the local CPU.
However, using the in-kernel cross-call in the msr driver
tends to be less invasive, so do that -- by-default.
'-m' remains to get the old behaviour.
Signed-off-by: Len Brown <len.brown@intel.com>
Pull Kbuild fixes from Masahiro Yamada:
"Nothing scary, just some random fixes:
- fix warnings of host programs
- fix "make tags" when COMPILED_SOURCE=1 is specified along with O=
- clarify help message of C=1 option
- fix dependency for ncurses compatibility check
- fix "make headers_install" for fakechroot environment"
* tag 'kbuild-fixes-v4.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: fix sparse warnings in nconfig
kbuild: fix header installation under fakechroot environment
kconfig: Check for libncurses before menuconfig
Kbuild: tiny correction on `make help`
tags: honor COMPILED_SOURCE with apart output directory
genksyms: add printf format attribute to error_with_pos()
Pull timer fix from Eric Biederman:
"This fixes an issue of confusing injected signals with the signals
from posix timers that has existed since posix timers have been in the
kernel.
This patch is slightly simpler than my earlier version of this patch
as I discovered in testing that I had misspelled "#ifdef
CONFIG_POSIX_TIMERS". So I deleted that unnecessary test and made
setting of resched_timer uncondtional.
I have tested this and verified that without this patch there is a
nasty hang that is easy to trigger, and with this patch everything
works properly"
Thomas Gleixner dixit:
"It fixes the problem at hand and covers the ptrace case as well, which
I missed.
Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de>"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
signal: Only reschedule timers on signals timers have sent
A recent commit included linux/slab.h in linux/irq.h. This breaks the build
of vdso32 on a 64-bit kernel.
The reason is that linux/irq.h gets included into the vdso code via
linux/interrupt.h which is included from asm/mshyperv.h. That makes the
32-bit vdso compile fail, because slab.h includes the pgtable headers for
64-bit on a 64-bit build.
Neither linux/clocksource.h nor linux/interrupt.h are needed in the
mshyperv.h header file itself - it has a dependency on <linux/atomic.h>.
Remove the includes and unbreak the build.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Fixes: dee863b571 ("hv: export current Hyper-V clocksource")
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1706231038460.2647@nanos
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The --debug option now pre-pends each row with
the number of micro-seconds [usec] to collect
the finishing snapshot for that row.
Signed-off-by: Len Brown <len.brown@intel.com>
Skylake has some new counters, and they were erroneously
exempt from --show and --hide
eg.
turbostat --quiet --show CPU
CPU Totl%C0 Any%C0 GFX%C0 CPUGFX%
- 116.73 90.56 85.69 79.00
0 117.78 91.38 86.47 79.71
2
1
3
is now
CPU
-
0
2
1
3
Signed-off-by: Len Brown <len.brown@intel.com>
Pull powerpc fixes from Michael Ellerman:
"Some more powerpc fixes for 4.12. Most of these actually came in last
week but got held up for some more testing.
- three fixes for kprobes/ftrace/livepatch interactions.
- properly handle data breakpoints when using the Radix MMU.
- fix for perf sampling of registers during call_usermodehelper().
- properly initialise the thread_info on our emergency stacks
- add an explicit flush when doing TLB invalidations for a process
using NPU2.
Thanks to: Alistair Popple, Naveen N. Rao, Nicholas Piggin, Ravi
Bangoria, Masami Hiramatsu"
* tag 'powerpc-4.12-7' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64: Initialise thread_info for emergency stacks
powerpc/powernv/npu-dma: Add explicit flush when sending an ATSD
powerpc/perf: Fix oops when kthread execs user process
powerpc/64s: Handle data breakpoints in Radix mode
powerpc/kprobes: Skip livepatch_handler() for jprobes
powerpc/ftrace: Pass the correct stack pointer for DYNAMIC_FTRACE_WITH_REGS
powerpc/kprobes: Pause function_graph tracing during jprobes handling
Pull ACPI fix from Rafael Wysocki:
"This fixes the ACPI-based enumeration of some I2C and SPI devices
broken in 4.11.
Specifics:
- I2C and SPI devices are expected to be enumerated by the I2C and
SPI subsystems, respectively, but due to a change made during the
4.11 cycle, in some cases the ACPI core marks them as already
enumerated which causes the I2C and SPI subsystems to overlook
them, so fix that (Jarkko Nikula)"
* tag 'acpi-4.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / scan: Fix enumeration for special SPI and I2C devices
Pull i2c fix from Wolfram Sang.
* 'i2c/for-current-fixed' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: imx: Use correct function to write to register
Pull GPIO fix from Linus Walleij:
"A single GPIO patch fixing the compatible string for the MVEBU PWM
controller embedded in the GPIO controller before we release v4.12.
Hopefully"
* tag 'gpio-v4.12-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
gpio: mvebu: change compatible string for PWM support
Pull sound fixes from Takashi Iwai:
"Nothing exciting here, just a few stable fixes:
- suppress spurious kernel WARNING in PCM core
- fix potential spin deadlock at error handling in firewire
- HD-audio PCI ID addition / fixup"
* tag 'sound-4.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda - Apply quirks to Broxton-T, too
ALSA: firewire-lib: Fix stall of process context at packet error
ALSA: pcm: Don't treat NULL chmap as a fatal error
ALSA: hda - Add Coffelake PCI ID
Pull drm fixes from Dave Airlie:
"A varied bunch of fixes, one for an API regression with connectors.
Otherwise amdgpu and i915 have a bunch of varied fixes, the shrinker
ones being the most important"
* tag 'drm-fixes-for-v4.12-rc7' of git://people.freedesktop.org/~airlied/linux:
drm: Fix GETCONNECTOR regression
drm/radeon: add a quirk for Toshiba Satellite L20-183
drm/radeon: add a PX quirk for another K53TK variant
drm/amdgpu: adjust default display clock
drm/amdgpu/atom: fix ps allocation size for EnableDispPowerGating
drm/amdgpu: add Polaris12 DID
drm/i915: Don't enable backlight at setup time.
drm/i915: Plumb the correct acquire ctx into intel_crtc_disable_noatomic()
drm/i915: Fix deadlock witha the pipe A quirk during resume
drm/i915: Remove __GFP_NORETRY from our buffer allocator
drm/i915: Encourage our shrinker more when our shmemfs allocations fails
drm/i915: Differentiate between sw write location into ring and last hw read
Pull random fixes from Ted Ts'o:
"Fix some locking and gcc optimization issues from the most recent
random_for_linus_stable pull request"
* tag 'random_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
random: silence compiler warnings and fix race
Pull device mapper fixes from Mike Snitzer:
- a revert of a DM mirror commit that has proven to make the code prone
to crash
- a DM io reference count fix that resolves a NULL pointer seen when
issuing discards to a DM mirror target's device whose mirror legs do
not all support discards
- a couple DM integrity fixes
* tag 'for-4.12/dm-fixes-4' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm io: fix duplicate bio completion due to missing ref count
dm integrity: fix to not disable/enable interrupts from interrupt context
Revert "dm mirror: use all available legs on multiple failures"
dm integrity: reject mappings too large for device
Some hardware have clusters with different idle states. The current code does
not support this and fails as it expects all the idle states to be identical.
Because of this, the Mediatek mtk8173 had to create the same idle state for a
big.Little system and now the Hisilicon 960 is facing the same situation.
Solve this by simply assuming the multiple driver will be needed for all the
platforms using the ARM generic cpuidle driver which makes sense because of the
different topologies we can support with a single kernel for ARM32 or ARM64.
Every CPU has its own driver, so every single CPU can specify in the DT the
idle states.
This simple approach allows to support the future dynamIQ system, current SMP
and HMP.
Tested on:
- 96boards: Hikey 620
- 96boards: Hikey 960
- 96boards: dragonboard410c
- Mediatek 8173
Tested-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In the current model the max/min perf limits are a fraction of current
user space limits to the allowed max_freq or 100% for global limits.
This results in wrong ratio limits calculation because of rounding
issues for some user space limits.
Initially we tried to solve this issue by issue by having more shift
bits to increase precision. Still there are isolated cases where we still
have error.
This can be avoided by using ratios all together. Since the way we get
cpuinfo.max_freq is by multiplying scaling factor to max ratio, we can
easily keep the max/min ratios in terms of ratios and not fractions.
For example:
if the max ratio = 36
cpuinfo.max_freq = 36 * 100000 = 3600000
Suppose user space sets a limit of 1200000, then we can calculate
max ratio limit as
= 36 * 1200000 / 3600000
= 12
This will be correct for any user limits.
The other advantage is that, we don't need to do any calculation in the
fast path as ratio limit is already calculated via set_policy() callback.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq_quick_get() allows cpufreq drivers to over-ride cpu_khz
that is otherwise reported in x86 /proc/cpuinfo "cpu MHz".
There are four problems with this scheme,
any of them is sufficient justification to delete it.
1. Depending on which cpufreq driver is loaded, the behavior
of this field is different.
2. Distros complain that they have to explain to users
why and how this field changes. Distros have requested a constant.
3. The two major providers of this information, acpi_cpufreq
and intel_pstate, both "get it wrong" in different ways.
acpi_cpufreq lies to the user by telling them that
they are running at whatever frequency was last
requested by software.
intel_pstate lies to the user by telling them that
they are running at the average frequency computed
over an undefined measurement. But an average computed
over an undefined interval, is itself, undefined...
4. On modern processors, user space utilities, such as
turbostat(1), are more accurate and more precise, while
supporing concurrent measurement over arbitrary intervals.
Users who have been consulting /proc/cpuinfo to
track changing CPU frequency will be dissapointed that
it no longer wiggles -- perhaps being unaware of the
limitations of the information they have been consuming.
Yes, they can change their scripts to look in sysfs
cpufreq/scaling_cur_frequency. Here they will find the same
data of dubious quality here removed from /proc/cpuinfo.
The value in sysfs will be addressed in a subsequent patch
to address issues 1-3, above.
Issue 4 will remain -- users that really care about
accurate frequency information should not be using either
proc or sysfs kernel interfaces.
They should be using using turbostat(8), or a similar
purpose-built analysis tool.
Signed-off-by: Len Brown <len.brown@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
pointer freq_table can be made static as it does not need to be in
global scope.
Cleans up sparse warning:
"symbol 'freq_table' was not declared. Should it be static?"
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
