Sometimes users have turbostat running in interval mode
when they take processors offline/online.
Previously, turbostat would survive, but not gracefully.
Tighten up the error checking so turbostat notices
changesn sooner, and print just 1 line on change:
turbostat: re-initialized with num_cpus %d
Signed-off-by: Len Brown <len.brown@intel.com>
turbostat uses /dev/cpu/*/msr interface to read MSRs.
For modern systems, it reads 10 MSR/CPU. This can
be observed as 10 "Function Call Interrupts"
per CPU per sample added to /proc/interrupts.
This overhead is measurable on large idle systems,
and as Yoquan Song pointed out, it can even trick
cpuidle into thinking the system is busy.
Here turbostat re-schedules itself in-turn to each
CPU so that its MSR reads will always be local.
This replaces the 10 "Function Call Interrupts"
with a single "Rescheduling interrupt" per sample
per CPU.
On an idle 32-CPU system, this shifts some residency from
the shallow c1 state to the deeper c7 state:
# ./turbostat.old -s
%c0 GHz TSC %c1 %c3 %c6 %c7 %pc2 %pc3 %pc6 %pc7
0.27 1.29 2.29 0.95 0.02 0.00 98.77 20.23 0.00 77.41 0.00
0.25 1.24 2.29 0.98 0.02 0.00 98.75 20.34 0.03 77.74 0.00
0.27 1.22 2.29 0.54 0.00 0.00 99.18 20.64 0.00 77.70 0.00
0.26 1.22 2.29 1.22 0.00 0.00 98.52 20.22 0.00 77.74 0.00
0.26 1.38 2.29 0.78 0.02 0.00 98.95 20.51 0.05 77.56 0.00
^C
i# ./turbostat.new -s
%c0 GHz TSC %c1 %c3 %c6 %c7 %pc2 %pc3 %pc6 %pc7
0.27 1.20 2.29 0.24 0.01 0.00 99.49 20.58 0.00 78.20 0.00
0.27 1.22 2.29 0.25 0.00 0.00 99.48 20.79 0.00 77.85 0.00
0.27 1.20 2.29 0.25 0.02 0.00 99.46 20.71 0.03 77.89 0.00
0.28 1.26 2.29 0.25 0.01 0.00 99.46 20.89 0.02 77.67 0.00
0.27 1.20 2.29 0.24 0.01 0.00 99.48 20.65 0.00 78.04 0.00
cc: Youquan Song <youquan.song@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
turbostat -s
cuts down on the amount of output, per user request.
also treak some output whitespace and the man page.
Signed-off-by: Len Brown <len.brown@intel.com>
This includes initial support for the recently published ACPI 5.0 spec.
In particular, support for the "hardware-reduced" bit that eliminates
the dependency on legacy hardware.
APEI has patches resulting from testing on real hardware.
Plus other random fixes.
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux: (52 commits)
acpi/apei/einj: Add extensions to EINJ from rev 5.0 of acpi spec
intel_idle: Split up and provide per CPU initialization func
ACPI processor: Remove unneeded variable passed by acpi_processor_hotadd_init V2
ACPI processor: Remove unneeded cpuidle_unregister_driver call
intel idle: Make idle driver more robust
intel_idle: Fix a cast to pointer from integer of different size warning in intel_idle
ACPI: kernel-parameters.txt : Add intel_idle.max_cstate
intel_idle: remove redundant local_irq_disable() call
ACPI processor: Fix error path, also remove sysdev link
ACPI: processor: fix acpi_get_cpuid for UP processor
intel_idle: fix API misuse
ACPI APEI: Convert atomicio routines
ACPI: Export interfaces for ioremapping/iounmapping ACPI registers
ACPI: Fix possible alignment issues with GAS 'address' references
ACPI, ia64: Use SRAT table rev to use 8bit or 16/32bit PXM fields (ia64)
ACPI, x86: Use SRAT table rev to use 8bit or 32bit PXM fields (x86/x86-64)
ACPI: Store SRAT table revision
ACPI, APEI, Resolve false conflict between ACPI NVS and APEI
ACPI, Record ACPI NVS regions
ACPI, APEI, EINJ, Refine the fix of resource conflict
...
Field names were shortened: "pkg" is now "pk", "core" is now "cr"
Signed-off-by: Arun Thomas <arun.thomas@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Reduce columns for package number to 1.
If you can afford more than 9 packages,
you can also afford a terminal with more than 80 columns:-)
Also shave a column also off the package C-states
Signed-off-by: Len Brown <len.brown@intel.com>
Follow kernel coding style traditions more closely.
Delete typedef, re-name "per cpu counters" to
simply be counters etc.
This patch changes no functionality.
Suggested-by: Thiago Farina <tfransosi@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
bug could cause false positive on indicating
presence of invarient TSC or APERF support.
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
MSR_IA32_ENERGY_PERF_BIAS first became available on Westmere Xeon.
It is implemented in all Sandy Bridge processors -- mobile, desktop and server.
It is expected to become increasingly important in subsequent generations.
x86_energy_perf_policy is a user-space utility to set the
hardware energy vs performance policy hint in the processor.
Most systems would benefit from "x86_energy_perf_policy normal"
at system startup, as the hardware default is maximum performance
at the expense of energy efficiency.
See x86_energy_perf_policy.8 man page for more information.
Background:
Linux-2.6.36 added "epb" to /proc/cpuinfo to indicate
if an x86 processor supports MSR_IA32_ENERGY_PERF_BIAS,
without actually modifying the MSR.
In March, 2010, Venkatesh Pallipadi proposed a small driver
that programmed MSR_IA32_ENERGY_PERF_BIAS, based on
the cpufreq governor in use. It also offered
a boot-time cmdline option to override.
http://lkml.org/lkml/2010/3/4/457
But hiding the hardware policy behind the
governor choice was deemed "kinda icky".
In June, 2010, I proposed a generic user/kernel API to
generalize the power/performance policy trade-off.
"RFC: /sys/power/policy_preference"
http://lkml.org/lkml/2010/6/16/399
That is my preference for implementing this capability,
but I received no support on the list.
So in September, 2010, I sent x86_energy_perf_policy.c to LKML,
a user-space utility that scribbles directly to the MSR.
http://lkml.org/lkml/2010/9/28/246
Here is that same utility, after responding to some review feedback,
to live in tools/power/, where it is easily found.
Signed-off-by: Len Brown <len.brown@intel.com>
turbostat is a Linux tool to observe proper operation
of Intel(R) Turbo Boost Technology.
turbostat displays the actual processor frequency
on x86 processors that include APERF and MPERF MSRs.
Note that turbostat is of limited utility on Linux
kernels 2.6.29 and older, as acpi_cpufreq cleared
APERF/MPERF up through that release.
On Intel Core i3/i5/i7 (Nehalem) and newer processors,
turbostat also displays residency in idle power saving states,
which are necessary for diagnosing any cpuidle issues
that may have an effect on turbo-mode.
See the turbostat.8 man page for example usage.
Signed-off-by: Len Brown <len.brown@intel.com>
