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alistair23-linux/arch/x86/kernel
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Rafael J. Wysocki 7d5905dc14 x86 / CPU: Always show current CPU frequency in /proc/cpuinfo 
After commit 890da9cf09 (Revert "x86: do not use cpufreq_quick_get()
for /proc/cpuinfo "cpu MHz"") the "cpu MHz" number in /proc/cpuinfo
on x86 can be either the nominal CPU frequency (which is constant)
or the frequency most recently requested by a scaling governor in
cpufreq, depending on the cpufreq configuration.  That is somewhat
inconsistent and is different from what it was before 4.13, so in
order to restore the previous behavior, make it report the current
CPU frequency like the scaling_cur_freq sysfs file in cpufreq.

To that end, modify the /proc/cpuinfo implementation on x86 to use
aperfmperf_snapshot_khz() to snapshot the APERF and MPERF feedback
registers, if available, and use their values to compute the CPU
frequency to be reported as "cpu MHz".

However, do that carefully enough to avoid accumulating delays that
lead to unacceptable access times for /proc/cpuinfo on systems with
many CPUs.  Run aperfmperf_snapshot_khz() once on all CPUs
asynchronously at the /proc/cpuinfo open time, add a single delay
upfront (if necessary) at that point and simply compute the current
frequency while running show_cpuinfo() for each individual CPU.

Also, to avoid slowing down /proc/cpuinfo accesses too much, reduce
the default delay between consecutive APERF and MPERF reads to 10 ms,
which should be sufficient to get large enough numbers for the
frequency computation in all cases.

Fixes: 890da9cf09 (Revert "x86: do not use cpufreq_quick_get() for /proc/cpuinfo "cpu MHz"")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
 		2017-11-15 19:46:50 +01:00
..
acpi x86/virt, x86/acpi: Add test for ACPI_FADT_NO_VGA 2017-11-10 10:03:13 +01:00
apic Merge branch 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 19:07:38 -08:00
cpu x86 / CPU: Always show current CPU frequency in /proc/cpuinfo 2017-11-15 19:46:50 +01:00
fpu Merge branch 'linus' into x86/asm, to pick up fixes and resolve conflicts 2017-11-07 10:53:06 +01:00
kprobes Merge branch 'linus' into perf/core, to fix conflicts 2017-11-07 10:30:18 +01:00
.gitignore
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Makefile x86/umip: Add emulation code for UMIP instructions 2017-11-08 11:16:22 +01:00
alternative.c kprobes, x86/alternatives: Use text_mutex to protect smp_alt_modules 2017-11-07 12:20:09 +01:00
amd_gart_64.c x86: remove arch specific dma_supported implementation 2017-06-28 06:54:46 -07:00
amd_nb.c x86/cpu/AMD: Apply the Erratum 688 fix when the BIOS doesn't 2017-10-22 13:06:02 +02:00
apb_timer.c Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-25 14:30:04 -08:00
aperture_64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
apm_32.c dmi: Mark all struct dmi_system_id instances const 2017-09-14 11:59:30 +02:00
asm-offsets.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
asm-offsets_32.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
asm-offsets_64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
audit_64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bootflag.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
check.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cpuid.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-12 19:25:04 -08:00
crash.c resource: Fix resource_size.cocci warnings 2017-11-07 20:44:56 +01:00
crash_dump_32.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crash_dump_64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
devicetree.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
doublefault.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dumpstack.c x86/asm/32: Remove a bunch of '& 0xffff' from pt_regs segment reads 2017-07-30 12:04:41 +02:00
dumpstack_32.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dumpstack_64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
e820.c x86/boot/e820: Add support to determine the E820 type of an address 2017-07-18 11:38:01 +02:00
early-quirks.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
early_printk.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ebda.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
eisa.c x86/eisa: Add missing include 2017-08-31 21:34:48 +02:00
espfix_64.c locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() 2017-10-25 11:01:08 +02:00
ftrace.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ftrace_32.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ftrace_64.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
head32.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
head64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
head_32.S Merge branch 'linus' into x86/asm, to pick up fixes and resolve conflicts 2017-11-07 10:53:06 +01:00
head_64.S Merge branch 'linus' into x86/asm, to pick up fixes and resolve conflicts 2017-11-07 10:53:06 +01:00
hpet.c x86/hpet: Cure interface abuse in the resume path 2017-08-01 13:02:37 +02:00
hw_breakpoint.c x86/kernel: Audit and remove any unnecessary uses of module.h 2016-07-14 15:06:41 +02:00
i8237.c
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i8253.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
i8259.c Merge branch 'linus' into x86/apic, to resolve conflicts 2017-11-07 10:51:10 +01:00
idt.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 18:29:23 -08:00
io_delay.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ioport.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq.c x86/irq: Simplify hotplug vector accounting 2017-09-25 20:52:02 +02:00
irq_32.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq_64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq_work.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irqinit.c Merge branch 'linus' into x86/apic, to resolve conflicts 2017-11-07 10:51:10 +01:00
itmt.c sched/x86: Remove unnecessary TBM3 check to update topology 2017-01-19 08:42:37 +01:00
jump_label.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kdebugfs.c x86, mpparse, x86/acpi, x86/PCI, x86/dmi, SFI: Use memremap() for RAM mappings 2017-07-18 11:37:58 +02:00
kexec-bzimage64.c x86/boot/e820: Rename the e820_table_firmware to e820_table_kexec 2017-07-05 10:09:02 +02:00
kgdb.c sched/x86: Add 'struct inactive_task_frame' to better document the sleeping task stack frame 2016-08-24 12:27:41 +02:00
ksysfs.c x86/sysfs: Fix off-by-one error in loop termination 2017-09-25 09:36:16 +02:00
kvm.c Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 17:04:36 -08:00
kvmclock.c X86/KVM: Clear encryption attribute when SEV is active 2017-11-07 15:36:00 +01:00
ldt.c Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 14:13:48 -08:00
livepatch.c livepatch/x86: apply alternatives and paravirt patches after relocations 2016-08-18 23:41:55 +02:00
machine_kexec_32.c x86/idt: Consolidate IDT invalidation 2017-08-29 12:07:26 +02:00
machine_kexec_64.c x86/mm, kexec: Fix memory corruption with SME on successive kexecs 2017-07-30 12:09:12 +02:00
mmconf-fam10h_64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
module.c x86/module: Detect and skip invalid relocations 2017-11-05 09:52:16 +01:00
mpparse.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
msr.c x86/msr: Remove bogus cleanup from the error path 2016-12-25 10:47:41 +01:00
nmi.c locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() 2017-10-25 11:01:08 +02:00
nmi_selftest.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
paravirt-spinlocks.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
paravirt.c locking/paravirt: Use new static key for controlling call of virt_spin_lock() 2017-10-10 11:50:12 +02:00
paravirt_patch_32.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
paravirt_patch_64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci-calgary_64.c x86, calgary: Convert timers to use timer_setup() 2017-11-02 15:50:32 -07:00
pci-dma.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci-iommu_table.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci-nommu.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci-swiotlb.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pcspeaker.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
perf_regs.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
platform-quirks.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pmem.c resource: Provide resource struct in resource walk callback 2017-11-07 15:35:57 +01:00
probe_roms.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
process.c Merge branch 'linus' into x86/asm, to pick up fixes and resolve conflicts 2017-11-07 10:53:06 +01:00
process_32.c x86/entry/64: Remove all remaining direct thread_struct::sp0 reads 2017-11-02 11:04:47 +01:00
process_64.c x86/entry/64: Remove thread_struct::sp0 2017-11-02 11:04:48 +01:00
ptrace.c x86/arch_prctl/64: Rename do_arch_prctl() to do_arch_prctl_64() 2017-03-20 16:10:32 +01:00
pvclock.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/nmi.h> 2017-03-02 08:42:30 +01:00
quirks.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
reboot.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
reboot_fixups_32.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
relocate_kernel_32.S
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relocate_kernel_64.S x86/mm, kexec: Fix memory corruption with SME on successive kexecs 2017-07-30 12:09:12 +02:00
resource.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rtc.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
setup.c Merge branch 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 19:07:38 -08:00
setup_percpu.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
signal.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
signal_compat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
smp.c x86/tracing: Disentangle pagefault and resched IPI tracing key 2017-08-29 11:42:29 +02:00
smpboot.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 18:29:23 -08:00
stacktrace.c x86/stacktrace: Avoid recording save_stack_trace() wrappers 2017-09-29 19:44:03 +02:00
step.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sys_x86_64.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sysfb.c
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sysfb_efi.c Merge branch 'linus' into efi/core, to pick up fixes 2016-05-07 07:00:07 +02:00
sysfb_simplefb.c x86/sysfb: Fix lfb_size calculation 2016-11-16 09:38:23 +01:00
tboot.c iommu/vt-d: Correctly disable Intel IOMMU force on 2017-06-15 16:41:10 +02:00
tce_64.c x86/cpufeature: Remove cpu_has_clflush 2016-03-31 13:35:09 +02:00
time.c Merge branch 'linus' into x86/apic, to resolve conflicts 2017-11-07 10:51:10 +01:00
tls.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tls.h
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topology.c
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trace_clock.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tracepoint.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
traps.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 18:29:23 -08:00
tsc.c Merge branch 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 19:07:38 -08:00
tsc_msr.c x86/tsc: Set TSC_KNOWN_FREQ and TSC_RELIABLE flags on Intel Atom SoCs 2016-11-18 10:58:31 +01:00
tsc_sync.c Merge branch 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 19:07:38 -08:00
umip.c x86/umip: Force a page fault when unable to copy emulated result to user 2017-11-08 11:16:22 +01:00
unwind_frame.c x86/unwind: Disable unwinder warnings on 32-bit 2017-10-10 12:49:49 +02:00
unwind_guess.c x86/unwind: Add the ORC unwinder 2017-07-26 13:18:20 +02:00
unwind_orc.c x86/unwind: Disable KASAN checking in the ORC unwinder 2017-11-08 10:21:49 +01:00
uprobes.c uprobes/x86: Use existing definitions for segment override prefixes 2017-11-01 21:50:08 +01:00
verify_cpu.S x86/boot: Annotate verify_cpu() as a callable function 2017-09-28 09:39:03 +02:00
vm86_32.c Merge branch 'linus' into x86/asm, to pick up fixes and resolve conflicts 2017-11-07 10:53:06 +01:00
vmlinux.lds.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vsmp_64.c x86/apic: Remove unused callbacks 2017-09-25 20:51:58 +02:00
x86_init.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 18:29:23 -08:00