Pass clocksource pointer to the read() callback for clocksources. This
allows us to share the callback between multiple instances.
[hugh@veritas.com: fix powerpc build of clocksource pass clocksource mods]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PowerPC has been a long time user of the generic RTC abstraction, so hook up
rtc-generic:
- Create the "rtc-generic" platform device if ppc_md.get_rtc_time is set,
- Kill rtc-ppc, as rtc-generic offers the same functionality in a more
generic way, and supports autoloading through udev.
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
* 'cpus4096-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (66 commits)
x86: export vector_used_by_percpu_irq
x86: use logical apicid in x2apic_cluster's x2apic_cpu_mask_to_apicid_and()
sched: nominate preferred wakeup cpu, fix
x86: fix lguest used_vectors breakage, -v2
x86: fix warning in arch/x86/kernel/io_apic.c
sched: fix warning in kernel/sched.c
sched: move test_sd_parent() to an SMP section of sched.h
sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0
sched: activate active load balancing in new idle cpus
sched: bias task wakeups to preferred semi-idle packages
sched: nominate preferred wakeup cpu
sched: favour lower logical cpu number for sched_mc balance
sched: framework for sched_mc/smt_power_savings=N
sched: convert BALANCE_FOR_xx_POWER to inline functions
x86: use possible_cpus=NUM to extend the possible cpus allowed
x86: fix cpu_mask_to_apicid_and to include cpu_online_mask
x86: update io_apic.c to the new cpumask code
x86: Introduce topology_core_cpumask()/topology_thread_cpumask()
x86: xen: use smp_call_function_many()
x86: use work_on_cpu in x86/kernel/cpu/mcheck/mce_amd_64.c
...
Fixed up trivial conflict in kernel/time/tick-sched.c manually
The cpu time spent by the idle process actually doing something is
currently accounted as idle time. This is plain wrong, the architectures
that support VIRT_CPU_ACCOUNTING=y can do better: distinguish between the
time spent doing nothing and the time spent by idle doing work. The first
is accounted with account_idle_time and the second with account_system_time.
The architectures that use the account_xxx_time interface directly and not
the account_xxx_ticks interface now need to do the check for the idle
process in their arch code. In particular to improve the system vs true
idle time accounting the arch code needs to measure the true idle time
instead of just testing for the idle process.
To improve the tick based accounting as well we would need an architecture
primitive that can tell us if the pt_regs of the interrupted context
points to the magic instruction that halts the cpu.
In addition idle time is no more added to the stime of the idle process.
This field now contains the system time of the idle process as it should
be. On systems without VIRT_CPU_ACCOUNTING this will always be zero as
every tick that occurs while idle is running will be accounted as idle
time.
This patch contains the necessary common code changes to be able to
distinguish idle system time and true idle time. The architectures with
support for VIRT_CPU_ACCOUNTING need some changes to exploit this.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The utimescaled / stimescaled fields in the task structure and the
global cpustat should be set on all architectures. On s390 the calls
to account_user_time_scaled and account_system_time_scaled never have
been added. In addition system time that is accounted as guest time
to the user time of a process is accounted to the scaled system time
instead of the scaled user time.
To fix the bugs and to prevent future forgetfulness this patch merges
account_system_time_scaled into account_system_time and
account_user_time_scaled into account_user_time.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Michael Neuling <mikey@neuling.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Impact: change calling convention of existing clock_event APIs
struct clock_event_timer's cpumask field gets changed to take pointer,
as does the ->broadcast function.
Another single-patch change. For safety, we BUG_ON() in
clockevents_register_device() if it's not set.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Since we started using the generic timekeeping code, we haven't had a
powerpc-specific version of do_gettimeofday, and hence there is now
nothing that reads the do_gtod variable in arch/powerpc/kernel/time.c.
This therefore removes it and the code that sets it.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Currently the clock_gettime implementation in the VDSO produces a
result with microsecond resolution for the cases that are handled
without a system call, i.e. CLOCK_REALTIME and CLOCK_MONOTONIC. The
nanoseconds field of the result is obtained by computing a
microseconds value and multiplying by 1000.
This changes the code in the VDSO to do the computation for
clock_gettime with nanosecond resolution. That means that the
resolution of the result will ultimately depend on the timebase
frequency.
Because the timestamp in the VDSO datapage (stamp_xsec, the real time
corresponding to the timebase count in tb_orig_stamp) is in units of
2^-20 seconds, it doesn't have sufficient resolution for computing a
result with nanosecond resolution. Therefore this adds a copy of
xtime to the VDSO datapage and updates it in update_gtod() along with
the other time-related fields.
Signed-off-by: Paul Mackerras <paulus@samba.org>
For some reason long ago I decided that we should zero out the time base
when we calibrate the decrementer. The problem is that this can be
harmful in SMP systems where the firmware has already synchronized the
time bases on the various cores.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
It's not even passed on to smp_call_function() anymore, since that
was removed. So kill it.
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Make a few things static in lparcfg.c
Make init and exit routines static in rtas_flash.c
Make things static in rtas_pci.c
Make some functions static in rtas.c
Make fops static in rtas-proc.c
Remove unneeded extern for do_gtod in smp.c
Make clocksource_init() static in time.c
Make last_tick_len and ticklen_to_xs static in time.c
Move the declaration of the pvr per-cpu into smp.h
Make kexec_smp_down() and kexec_stack static in machine_kexec_64.c
Don't return void in arch_teardown_msi_irqs() in msi.c
Move declaration of GregorianDay()into asm/time.h
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
As TICK_LENGTH_SHIFT is used for more than just the tick length, the name
isn't quite approriate anymore, so this renames it to NTP_SCALE_SHIFT.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This changes time_freq to a 64bit value and makes it static (the only outside
user had no real need to modify it). Intermediate values were already 64bit,
so the change isn't that big, but it saves a little in shifts by replacing
SHIFT_NSEC with TICK_LENGTH_SHIFT. PPM_SCALE is then used to convert between
user space and kernel space representation.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This moves the ability to scale cputime into generic code. This allows us
to fix the issue in kernel/timer.c (noticed by Balbir) where we could only
add an unscaled value to the scaled utime/stime.
This adds a cputime_to_scaled function. As before, the POWERPC version
does the scaling based on the last SPURR/PURR ratio calculated. The
generic and s390 (only other arch to implement asm/cputime.h) versions are
both NOPs.
Also moves the SPURR and PURR snapshots closer.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These hooks ensure that a decrementer interrupt is not pending when
suspending; otherwise, problems may occur on 6xx/7xx/7xxx-based
systems (except for powermacs, which use a separate suspend path).
For example, with deep sleep on the 831x, a pending decrementer will
cause a system freeze because the SoC thinks the decrementer interrupt
would have woken the system, but the core must have interrupts
disabled due to the setup required for deep sleep.
Changed via-pmu.c to use the new ppc_md hooks, and made the arch_*
functions call the generic_* functions unconditionally. -- paulus
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
We have multiple calls to has_feature being inlined, but gcc can't
be sure that the store via get_paca() doesn't alias the path to
cur_cpu_spec->feature.
Reorder to put the calls to read_purr and read_spurr adjacent to each
other. To add a sense of consistency, reorder the remaining lines to
perform parallel steps on purr and scaled purr of each line instead of
calculating and then using one value before going on to the next.
In addition, we can tell gcc that no SPURR means no PURR. The test is
completely hidden in the PURR case, and in the !PURR case the second test
is eliminated resulting in the simple register copy in the out-of-line
branch.
Further, gcc sees get_paca()->system_time referenced several times and
allocates a register to address it (shadowing r13) instead of caching its
value. Reading into a local varable saves the shadow of r13 and removes
a potentially duplicate load (between the nested if and its parent).
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
If CPU_FTR_PURR is not set, we will never set cpu_purr_data->initialized.
Checking via __get_cpu_var on 64 bit avoids one dependent load compared
to cpu_has_feature in the not-present case, and is always required when
it is present. The code is under CONFIG_VIRT_CPU_ACCOUNTING so 32 bit
will not be affected.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
timer_interrupt() was calculating per_cpu_offset several times, having to
start from the toc because of potential aliasing issues.
Placing both decrementer per_cpu varables in a struct and calculating
the address once with __get_cpu_var results in better code on both 32
and 64 bit.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Use __get_cpu_var(x) instead of per_cpu(x, smp_processor_id()), as it
is optimized on ppc64 to access the current cpu's per-cpu offset directly;
it's local_paca.offset instead of TOC->paca[local_paca->processor_id].offset.
This is the trivial portion, two functions with one use each.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
as its only called from time_init, which is __init.
Also remove unneeded forward declaration.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
If we get no user time and no system time allocated since the last
account_system_vtime, the system to user time ratio estimate can end
up dividing by zero.
This was causing a problem noticed by Balbir Singh.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
These don't need to be seen by everyone on every boot.
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Since powerpc started using CONFIG_GENERIC_CLOCKEVENTS, the
deterministic CPU accounting (CONFIG_VIRT_CPU_ACCOUNTING) has been
broken on powerpc, because we end up counting user time twice: once in
timer_interrupt() and once in update_process_times().
This fixes the problem by pulling the code in update_process_times
that updates utime and stime into a separate function called
account_process_tick. If CONFIG_VIRT_CPU_ACCOUNTING is not defined,
there is a version of account_process_tick in kernel/timer.c that
simply accounts a whole tick to either utime or stime as before. If
CONFIG_VIRT_CPU_ACCOUNTING is defined, then arch code gets to
implement account_process_tick.
This also lets us simplify the s390 code a bit; it means that the s390
timer interrupt can now call update_process_times even when
CONFIG_VIRT_CPU_ACCOUNTING is turned on, and can just implement a
suitable account_process_tick().
account_process_tick() now takes the task_struct * as an argument.
Tested both with and without CONFIG_VIRT_CPU_ACCOUNTING.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The decrementer in Book E and 4xx processors interrupts on the
transition from 1 to 0, rather than on the 0 to -1 transition as on
64-bit server and 32-bit "classic" (6xx/7xx/7xxx) processors. At the
moment we subtract 1 from the count of how many decrementer ticks are
required before the next interrupt before putting it into the
decrementer, which is correct for server/classic processors, but could
possibly cause the interrupt to happen too early on Book E and 4xx if
the timebase/decrementer frequency is low.
This fixes the problem by making set_dec subtract 1 from the count for
server and classic processors, instead of having the callers subtract
1. Since set_dec already had a bunch of ifdefs to handle different
processor types, there is no net increase in ugliness. :)
Note that calling set_dec(0) may not generate an interrupt on some
processors. To make sure that decrementer_set_next_event always calls
set_dec with an interval of at least 1 tick, we set min_delta_ns of
the decrementer_clockevent to correspond to 2 ticks (2 rather than 1
to compensate for truncations in the conversions between ticks and
ns).
This also removes a redundant call to set the decrementer to
0x7fffffff - it was already set to that earlier in timer_interrupt.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This adds POWERPC specific hooks for scaled time accounting.
POWER6 includes a SPURR register. The SPURR is based off the PURR register
but is scaled based on CPU frequency and issue rates. This gives a more
accurate account of the instructions used per task. The PURR and timebase
will be constant relative to the wall clock, irrespective of the CPU
frequency.
This implementation reads the SPURR register in account_system_vtime which
is only call called on context witch and hard and soft irq entry and exit.
The percentage of user and system time is then estimated using the ratio of
these accounted by the PURR. If the SPURR is not present, the PURR read.
An earlier implementation of this patch read the SPURR whenever the PURR
was read, which included the system call entry and exit path.
Unfortunately this showed a performance regression on lmbench runs, so was
re-implemented.
I've included the lmbench results here when run bare metal on POWER6. 1st
column is the unpatch results. 2nd column is the results using the below
patch and the 3rd is the % diff of these results from the base. 4th and
5th columns are the results and % differnce from the base using the older
patch (SPURR read in syscall entry/exit path).
Base Scaled-Acct SPURR-in-syscall
Result Result % diff Result % diff
Simple syscall: 0.3086 0.3086 0.0000 0.3452 11.8600
Simple read: 0.4591 0.4671 1.7425 0.5044 9.86713
Simple write: 0.4364 0.4366 0.0458 0.4731 8.40971
Simple stat: 2.0055 2.0295 1.1967 2.0669 3.06158
Simple fstat: 0.5962 0.5876 -1.442 0.6368 6.80979
Simple open/close: 3.1283 3.1009 -0.875 3.2088 2.57328
Select on 10 fd's: 0.8554 0.8457 -1.133 0.8667 1.32101
Select on 100 fd's: 3.5292 3.6329 2.9383 3.6664 3.88756
Select on 250 fd's: 7.9097 8.1881 3.5197 8.2242 3.97613
Select on 500 fd's: 15.2659 15.836 3.7357 15.873 3.97814
Select on 10 tcp fd's: 0.9576 0.9416 -1.670 0.9752 1.83792
Select on 100 tcp fd's: 7.248 7.2254 -0.311 7.2685 0.28283
Select on 250 tcp fd's: 17.7742 17.707 -0.375 17.749 -0.1406
Select on 500 tcp fd's: 35.4258 35.25 -0.496 35.286 -0.3929
Signal handler installation: 0.6131 0.6075 -0.913 0.647 5.52927
Signal handler overhead: 2.0919 2.1078 0.7600 2.1831 4.35967
Protection fault: 0.7345 0.7478 1.8107 0.8031 9.33968
Pipe latency: 33.006 16.398 -50.31 33.475 1.42368
AF_UNIX sock stream latency: 14.5093 30.910 113.03 30.715 111.692
Process fork+exit: 219.8 222.8 1.3648 229.37 4.35623
Process fork+execve: 876.14 873.28 -0.32 868.66 -0.8533
Process fork+/bin/sh -c: 2830 2876.5 1.6431 2958 4.52296
File /var/tmp/XXX write bw: 1193497 1195536 0.1708 118657 -0.5799
Pagefaults on /var/tmp/XXX: 3.1272 3.2117 2.7020 3.2521 3.99398
Also, kernel compile times show no difference with this patch applied.
[pbadari@us.ibm.com: Avoid unnecessary PURR reading]
Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The clockevent bootup message only needs to be KERN_INFO.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
In testing the new clocksource and clockevent code on a PPC601
processor, I discovered that the clockevent multiplier value for the
decrementer clockevent was overflowing. Because the RTCL register in
the 601 effectively counts at 1GHz (it doesn't actually, but it
increases by 128 every 128ns), and the shift value was 32, that meant
the multiplier value had to be 2^32, which won't fit in an unsigned
long on 32-bit. The same problem would arise on any platform where
the timebase frequency was 1GHz or more (not that we actually have any
such machines today).
This fixes it by reducing the shift value to 16. Doing the
calculations with a resolution of 2^-16 nanoseconds (15 femtoseconds)
should be quite adequate. :)
Signed-off-by: Paul Mackerras <paulus@samba.org>
On old powermacs, we sometimes set the decrementer to 1 in order to
trigger a decrementer interrupt, which we use to handle an interrupt
that was pending at the time when it was re-enabled. This was causing
the decrementer clock event device to call the event function for the
next event early, which was causing problems when high-res timers were
not enabled.
This fixes the problem by recording the timebase value at which the
next event should occur, and checking the current timebase against the
recorded value in timer_interrupt. If it isn't time for the next
event, it just reprograms the decrementer and returns.
This also subtracts 1 from the value stored into the decrementer,
which is appropriate because the decrementer interrupts on the
transition from 0 to -1, not when the decrementer reaches 0.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This registers a clock event structure for the decrementer and turns
on CONFIG_GENERIC_CLOCKEVENTS, which means that we now don't need
most of timer_interrupt(), since the work is done in generic code.
For secondary CPUs, their decrementer clockevent is registered when
the CPU comes up (the generic code automatically removes the
clockevent when the CPU goes down).
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
With these functions implemented we cooperate better with the generic
timekeeping code. This obsoletes the need for the timer sysdev as a bonus.
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Recent changes to the timekeeping code broke support for the PowerPC 601
processor which doesn't have the usual timebase facility but a slightly
different thing called (yuck) the RTC.
This fixes it, boot tested on an old 601 based PowerMac 7200.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Allow generic_calibrate_decr to work for 40x platforms. Given that the hardware
behavior is identical, this also changes the set_dec function to reload the PIT
on 40x to match the behavior 44x currently has.
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
This removes several duplicate includes from arch/powerpc/.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
From: Maynard Johnson <mpjohn@us.ibm.com>
This patch updates the existing arch/powerpc/oprofile/op_model_cell.c
to add in the SPU profiling capabilities. In addition, a 'cell' subdirectory
was added to arch/powerpc/oprofile to hold Cell-specific SPU profiling code.
Exports spu_set_profile_private_kref and spu_get_profile_private_kref which
are used by OProfile to store private profile information in spufs data
structures.
Also incorporated several fixes from other patches (rrn). Check pointer
returned from kzalloc. Eliminated unnecessary cast. Better error
handling and cleanup in the related area. 64-bit unsigned long parameter
was being demoted to 32-bit unsigned int and eventually promoted back to
unsigned long.
Signed-off-by: Carl Love <carll@us.ibm.com>
Signed-off-by: Maynard Johnson <mpjohn@us.ibm.com>
Signed-off-by: Bob Nelson <rrnelson@us.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
When booting a current kernel with CONFIG_PRINTK_TIME enabled you'll
see messages like:
[ 0.000000] time_init: decrementer frequency = 188.044000 MHz
[ 0.000000] time_init: processor frequency = 1504.352000 MHz
[3712914.436297] Console: colour dummy device 80x25
This cause by the initialisation of tb_to_ns_scale in time_init(), suddenly the
multiplication in sched_clock() now does something :). This patch modifies
sched_clock() to report the offset since the machine booted so the same
printk's now look like:
[ 0.000000] time_init: decrementer frequency = 188.044000 MHz
[ 0.000000] time_init: processor frequency = 1504.352000 MHz
[ 0.000135] Console: colour dummy device 80x25
Effectivly including the uptime in printk()s.
This patch makes tb_to_ns_scale and tb_to_ns_shift static and
read_mostly for good measure.
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Currently iSeries will recalibrate the cputime_factors in the first
settimeofday() call.
It seems the reason for doing this is to ensure a resaonable time delta after
time_init(). On current kernels (with udev), this call is made 40-60 seconds
into the boot process, by moving it to a late initcall it is called
approximately 5 seconds after time_init() is called. This is sufficient to
recalibrate the timebase.
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
CC: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
For POWERPC, stolen time accounts for cycles lost to the hypervisor or
PURR cycles attributed to the other SMT thread. Hence, when a PURR is
available, we should still calculate stolen time, irrespective of being
virtualised.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
cpu_purr_data is a per-cpu array used to account for stolen time on
partitioned systems. It used to be the case that cpus accessed each
others' cpu_purr_data, so each entry was protected by a spinlock.
However, the code was reworked ("Simplify stolen time calculation")
with the result that each cpu accesses its own cpu_purr_data and not
those of other cpus. This means we can get rid of the spinlock as
long as we're careful to disable interrupts when accessing
cpu_purr_data in process context.
Signed-off-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Greatly simplify the function smp_space_timers.
The stolen time calculation (per comment within the code) doesn't need the
half-jiffy stagger any more. There isn't an issue with bouncing off global
locks, so we really shouldn't need any sort of staggering at all.
However, the last_jiffy value still needs to be set. This removes the
extra stagger logic, and just sets the values.
This change should benefit applications that rely on barrier
synchronization, and will help cut down OS jitter.
Boot tested across the board (G5,power3,power4,power5,970mp blade).
Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
In calculating stolen time, we were trying to actually account for time
spent in the hypervisor. We don't really have enough information to do
that accurately, so don't try. Instead, we now calculate stolen time as
time that the current cpu thread is not actually dispatching instructions.
On chips without a PURR, we cannot do this, so stolen time will always
be zero. On chips with a PURR, this is merely the difference between
the elapsed PURR values and the elapsed TB values.
This gives us much more sane vaules from tools such as mpstat, even if
they are still a bit strange e.g. 2 busy threads on one cpu will both
appear to have 50% user time and 50% stolen time while 1 busy thread on
a cpu will look like 100% user on one of them and 100% idle on the other.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Remove struct pt_regs * from all handlers.
Also remove the regs argument from get_irq() functions.
Compile tested with arch/powerpc/config/* and
arch/ppc/configs/prep_defconfig
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
