For C1 and C2 states use cpu_ticks() to measure sleep time instead of much
slower ACPI timer. We can't do it for C3, as TSC may stop there. But it is
less important there as wake up latency is high any way.
For C1 and C2 states do not check/clear bus mastering activity status, as
it is important only for C3. As side effect it can make CPU enter C2 instead
of C3 if last BM activity was two sleeps back (unlike one before), but
that may be even good because of collecting more statistics. Premature BM
wakeup from C3, entered because of overestimation, can easily be worse then
entering C2 from both performance and power consumption points of view.
Together on dual Xeon E5645 system on sequential 512 bytes read test this
change makes cpu_idle_acpi() as fast as simplest cpu_idle_hlt() and only
few percents slower then cpu_idle_mwait(), while deeper states are still
actively used during idle periods.
To help with diagnostics, add C-state type into dev.cpu.X.cx_supported.
Sponsored by: iXsystems, Inc.
... from a user-set persistent limit on the said level.
Allow to set the user-imposed limit below current deepest available level
as the available levels may be dynamically changed by ACPI platform
in both directions.
Allow "Cmax" as an input value for cx_lowest sysctls to mean that there
is not limit and OS can use all available C-states.
Retire global cpu_cx_count as it no longer serves any meaningful
purpose.
Reviewed by: jhb, gianni, sbruno
Tested by: sbruno, Vitaly Magerya <vmagerya@gmail.com>
MFC after: 2 weeks
although by default only C1 is enabled (cx_lowest=0) and enabling deeper
states goes through acpi_cpu_set_cx_lowest which re-evaluates cpu_non_c3
MFC after: 2 weeks
cpu_non_c3 is already evaluated in acpi_cpu_cx_cst and in
acpi_cpu_set_cx_lowest.
Besides acpi_cpu_cx_list is not protected by any locking.
As a result also move setting of cpu_can_deep_sleep to more appropriate
places.
MFC after: 2 weeks
Adjust power_profile script to handle the new world order as well.
Some vendors are opting out of a C2 state and only defining C1 & C3. This
leads the acpi_cpu display to indicate that the machine supports C1 & C2
which is caused by the (mis)use of the index of the cx_state array as the
ACPI_STATE_CX value.
e.g. the code was pretending that cx_state[i] would
always convert to i by subtracting 1.
cx_state[2] == ACPI_STATE_C3
cx_state[1] == ACPI_STATE_C2
cx_state[0] == ACPI_STATE_C1
however, on certain machines this would lead to
cx_state[1] == ACPI_STATE_C3
cx_state[0] == ACPI_STATE_C1
This didn't break anything but led to a display of:
* dev.cpu.0.cx_supported: C1/1 C2/96
Instead of
* dev.cpu.0.cx_supported: C1/1 C3/96
MFC after: 2 weeks
processor objects. Instead of forcing the new-bus CPU objects to use
a unit number equal to pc_cpuid, adjust acpi_pcpu_get_id() to honor the
MADT IDs by default. As with the previous change, setting
debug.acpi.cpu_unordered to 1 in the loader will revert to the old
behavior.
Tested by: jimharris
MFC after: 1 month
one. Interestingly, these are actually the default for quite some time
(bus_generic_driver_added(9) since r52045 and bus_generic_print_child(9)
since r52045) but even recently added device drivers do this unnecessarily.
Discussed with: jhb, marcel
- While at it, use DEVMETHOD_END.
Discussed with: jhb
- Also while at it, use __FBSDID.
processors unless the invariant TSC bit of CPUID is set. Intel processors
may stop incrementing TSC when DPSLP# pin is asserted, according to Intel
processor manuals, i. e., TSC timecounter is useless if the processor can
enter deep sleep state (C3/C4). This problem was accidentally uncovered by
r222869, which increased timecounter quality of P-state invariant TSC, e.g.,
for Core2 Duo T5870 (Family 6, Model f) and Atom N270 (Family 6, Model 1c).
Reported by: Fabian Keil (freebsd-listen at fabiankeil dot de)
Ian FREISLICH (ianf at clue dot co dot za)
Tested by: Fabian Keil (freebsd-listen at fabiankeil dot de)
- Core2 Duo T5870 (C3 state available/enabled)
jkim - Xeon X5150 (C3 state unavailable)
safer for i386 because it can be easily over 4 GHz now. More worse, it can
be easily changed by user with 'machdep.tsc_freq' tunable (directly) or
cpufreq(4) (indirectly). Note it is intentionally not used in performance
critical paths to avoid performance regression (but we should, in theory).
Alternatively, we may add "virtual TSC" with lower frequency if maximum
frequency overflows 32 bits (and ignore possible incoherency as we do now).
function always returned the nominal frequency instead of current frequency
because we use RDTSC instruction to calculate difference in CPU ticks, which
is supposedly constant for the case. Now we support cpu_get_nominal_mhz()
for the case, instead. Note it should be just enough for most usage cases
because cpu_est_clockrate() is often times abused to find maximum frequency
of the processor.
ACPI specification sates that if P_LVL2_LAT > 100, then a system doesn't
support C2; if P_LVL3_LAT > 1000, then C3 is not supported.
But there are no such rules for Cx state data returned by _CST. If a
state is not supported it should not be included into the return
package. In other words, any latency value returned by _CST is valid,
it's up to the OS and/or user to decide whether to use it.
Submitted by: nork
Suggested by: mav
MFC after: 1 week
The main goal of this is to generate timer interrupts only when there is
some work to do. When CPU is busy interrupts are generating at full rate
of hz + stathz to fullfill scheduler and timekeeping requirements. But
when CPU is idle, only minimum set of interrupts (down to 8 interrupts per
second per CPU now), needed to handle scheduled callouts is executed.
This allows significantly increase idle CPU sleep time, increasing effect
of static power-saving technologies. Also it should reduce host CPU load
on virtualized systems, when guest system is idle.
There is set of tunables, also available as writable sysctls, allowing to
control wanted event timer subsystem behavior:
kern.eventtimer.timer - allows to choose event timer hardware to use.
On x86 there is up to 4 different kinds of timers. Depending on whether
chosen timer is per-CPU, behavior of other options slightly differs.
kern.eventtimer.periodic - allows to choose periodic and one-shot
operation mode. In periodic mode, current timer hardware taken as the only
source of time for time events. This mode is quite alike to previous kernel
behavior. One-shot mode instead uses currently selected time counter
hardware to schedule all needed events one by one and program timer to
generate interrupt exactly in specified time. Default value depends of
chosen timer capabilities, but one-shot mode is preferred, until other is
forced by user or hardware.
kern.eventtimer.singlemul - in periodic mode specifies how much times
higher timer frequency should be, to not strictly alias hardclock() and
statclock() events. Default values are 2 and 4, but could be reduced to 1
if extra interrupts are unwanted.
kern.eventtimer.idletick - makes each CPU to receive every timer interrupt
independently of whether they busy or not. By default this options is
disabled. If chosen timer is per-CPU and runs in periodic mode, this option
has no effect - all interrupts are generating.
As soon as this patch modifies cpu_idle() on some platforms, I have also
refactored one on x86. Now it makes use of MONITOR/MWAIT instrunctions
(if supported) under high sleep/wakeup rate, as fast alternative to other
methods. It allows SMP scheduler to wake up sleeping CPUs much faster
without using IPI, significantly increasing performance on some highly
task-switching loads.
Tested by: many (on i386, amd64, sparc64 and powerc)
H/W donated by: Gheorghe Ardelean
Sponsored by: iXsystems, Inc.
This reflects actual type used to store and compare child device orders.
Change is mostly done via a Coccinelle (soon to be devel/coccinelle)
semantic patch.
Verified by LINT+modules kernel builds.
Followup to: r212213
MFC after: 10 days
measured interval as upper bound. It should be more precise then just
assuming hz/2. For idle CPU it should be quite precise, for busy - not
worse then before.
state lower than the lowest one supported by the current CPU. This closes
some races with changes to the hw.acpi.cpu_cx_lowest sysctl while Cx
states for individual CPUs were changing (e.g. unplugging the AC adapter
of a laptop) that could result in panics.
Submitted by: Giovanni Trematerra
Tested by: David Demelier demelier dot david of gmail
MFC after: 3 days
Some current systems dynamically load SSDT(s) when _PDC/_OSC method
of Processor is evaluated. Other devices in ACPI namespace may access
objects defined in the dynamic SSDT. Drivers for such devices might
have to have a rather high priority, because of other dependencies.
Good example is acpi_ec driver for EC.
Thus we attach to Processors as early as possible to load the SSDTs
before any other drivers may try to evaluate control methods.
It also seems to be a natural order for a processor in a device
hierarchy.
On the other hand, some child devices on acpi cpu bus need to access
other system resources like PCI configuration space of chipset devices,
so they need to be probed and attached rather late.
For this reason we probe and attach the cpu bus at
SI_SUB_CONFIGURE:SI_ORDER_MIDDLE SYSINIT level.
In the future this could be done more elegantly via multipass.
Please note that acpi drivers that might access ACPI namespace from
device_identify will do that before _PDC/_OSC of Processors are evaluated.
Legacy cpu driver is not affected by this change.
PR: kern/142561 (in part)
Reviewed by: jhb
Silence from: acpi@
MFC after: 5 weeks
_PDC was deprecated in favor of _OSC long time ago, but it
seems that they still peacefully coexist and in some case
only _PDC is present.
Still _OSC provides a reacher interface and is capable to
report back its status.
If the status is non-zero, then report it, we may find
it useful to understand what firmware expects from OS.
Also clean up some comments that became less useful over time.
Reviewed by: njl, jhb, rpaulo
MFC after: 3 weeks
o acpi_hpet: auto-added 'wildcard' devices can be identified by
non-NULL handle attribute.
o acpi_ec: auto-add 'wildcard' devices can be identified by
unset (NULL) private attribute.
o acpi_cpu: use private instead of magic to store cpu id.
Reviewed by: jhb
Silence from: acpi@
MFC after: 2 weeks
X-MFC-Note: perhaps the ivar should stay for ABI stability
The newbus lock is responsible for protecting newbus internIal structures,
device states and devclass flags. It is necessary to hold it when all
such datas are accessed. For the other operations, softc locking should
ensure enough protection to avoid races.
Newbus lock is automatically held when virtual operations on the device
and bus are invoked when loading the driver or when the suspend/resume
take place. For other 'spourious' operations trying to access/modify
the newbus topology, newbus lock needs to be automatically acquired and
dropped.
For the moment Giant is also acquired in some key point (modules subsystem)
in order to avoid problems before the 8.0 release as module handlers could
make assumptions about it. This Giant locking should go just after
the release happens.
Please keep in mind that the public interface can be expanded in order
to provide more support, if there are really necessities at some point
and also some bugs could arise as long as the patch needs a bit of
further testing.
Bump __FreeBSD_version in order to reflect the newbus lock introduction.
Reviewed by: ed, hps, jhb, imp, mav, scottl
No answer by: ariff, thompsa, yongari
Tested by: pho,
G. Trematerra <giovanni dot trematerra at gmail dot com>,
Brandon Gooch <jamesbrandongooch at gmail dot com>
Sponsored by: Yahoo! Incorporated
Approved by: re (ksmith)
leading to a bug, when C-state does not decrease on sleep shorter then
declared transition latency. Fixing this deprecates workaround for broken
C-states on some hardware.
By the way, change state selecting logic a bit. Instead of last sleep
time use short-time average of it. Global interrupts rate in system is a
quite random value, to corellate subsequent sleeps so directly.
into acpi_cpu_startup() which is where all the other code to update this
global variable lives. This fixes a bug where cpu_cx_count was not updated
correctly if acpi_cpu_generic_cx_probe() returned early.
PR: kern/108581
Debugged by: Bruce Cran
Reviewed by: avg, njl, sepotvin
MFC after: 3 days
This is triggered only if BIOS configures ACPI_BITREG_BUS_MASTER_RLD
aka BRLD_EN_BM to 1.
Rationale:
1. we do not support C3 on PIIX4E
2. bus master activity need not break out of C2 state
3. because of CPU_QUIRK_NO_BM_CTRL quirk we may reset bus master
status which would result in immediate break out from C2
So if you have seen
cpu0: too many short sleeps, backing off to C1
with this chipset before you may want to try cx_lowest of C2 again.
Reviewed by: rpaulo (mentor), njl
Approved by: rpaulo (mentor)
the appropriate bit in the DEVACTB register.
This change allows the C2 state on those systems to work as expected.
Reviewed by: njl
Submitted by: Andriy Gapon <avg at icyb.net.ua>
MFC after: 1 week
CPUs to make sure idle threads are evicted from the softc before returning
from acpi_cpu_shutdown(). However, this is unnecessary since stop_cpus()
handles this for itself and at this point it's possible that our IPI will be
blocked (interrupts disabled).
Thanks to: Glen Leeder <glen.leeder / nokia.com>
MFC after: 3 days
needed at least to convince the BIOS to give us access to CPU freq
control on MacBooks.
Submitted by: Rui Paulo <rpaulo / fnop.net>
Approved by: re
MFC after: 5 days
While in the suspend path, this means the idle thread will just return
immediately rather than trying to enter C1-n. This helps in the case where
the chipset is powered down before the rest of the system and reads from
the cpu sleep registers begin returning immediately, causing the logic that
catches bad C2/C3 behavior to kick in. Observed on my Panasonic Y4.
MFC after: 3 days
(j/i) was being used and it was being incremented, not decremented as before.
Factor out this code into a common function and call it from both the common
and per-CPU case.
MFC after: 1 day
