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path: root/arch/x86/kernel/tsc_64.c
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2008-07-09x86: merge tsc_init and clocksource codeAlok Kataria
Unify the clocksource code. Unify the tsc_init code. Signed-off-by: Alok N Kataria <akataria@vmware.com> Signed-off-by: Dan Hecht <dhecht@vmware.com> Cc: Dan Hecht <dhecht@vmware.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09x86: merge the TSC cpu-freq codeAlok Kataria
Unify the TSC cpufreq code. Signed-off-by: Alok N Kataria <akataria@vmware.com> Signed-off-by: Dan Hecht <dhecht@vmware.com> Cc: Dan Hecht <dhecht@vmware.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09x86: merge tsc calibrationAlok Kataria
Merge the tsc calibration code for the 32bit and 64bit kernel. The paravirtualized calculate_cpu_khz for 64bit now points to the correct tsc_calibrate code as in 32bit. Original native_calculate_cpu_khz for 64 bit is now called as calibrate_cpu. Also moved the recalibrate_cpu_khz function in the common file. Note that this function is called only from powernow K7 cpu freq driver. Signed-off-by: Alok N Kataria <akataria@vmware.com> Signed-off-by: Dan Hecht <dhecht@vmware.com> Cc: Dan Hecht <dhecht@vmware.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09x86: merge sched_clock handlingAlok Kataria
Move the basic global variable definitions and sched_clock handling in the common "tsc.c" file. - Unify notsc kernel command line handling for 32 bit and 64bit. - Functional changes for 64bit. - "tsc_disabled" is updated if "notsc" is passed at boottime. - Fallback to jiffies for sched_clock, incase notsc is passed on commandline. Signed-off-by: Alok N Kataria <akataria@vmware.com> Signed-off-by: Dan Hecht <dhecht@vmware.com> Cc: Dan Hecht <dhecht@vmware.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-16Merge branch 'linus' into x86/timerstip-x86-timers-2008-06-16_09.20_MonIngo Molnar
2008-05-25x86: tsc_64.c make constant ULThomas Gleixner
arch/x86/kernel/tsc_64.c:245:13: warning: constant 0x100000000 is so big it is long Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-23x86: fix setup of cyc2ns in tsc_64.cThomas Gleixner
When the TSC is calibrated against the PIT due to the nonavailability of PMTIMER/HPET or due to SMI interference then the setup of the per CPU cyc2ns variables is skipped. This is unlikely to happen but it would definitely render sched_clock() unusable. This was introduced with commit 53d517cdbaac704352b3d0c10fecb99e0b54572e x86: scale cyc_2_nsec according to CPU frequency Update the per CPU cyc2ns variables in all exit pathes of tsc_calibrate. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
2008-04-19x86: tsc prevent time going backwardsThomas Gleixner
We already catch most of the TSC problems by sanity checks, but there is a subtle bug which has been in the code forever. This can cause time jumps in the range of hours. This was reported in: http://lkml.org/lkml/2007/8/23/96 and http://lkml.org/lkml/2008/3/31/23 I was able to reproduce the problem with a gettimeofday loop test on a dual core and a quad core machine which both have sychronized TSCs. The TSCs seems not to be perfectly in sync though, but the kernel is not able to detect the slight delta in the sync check. Still there exists an extremly small window where this delta can be observed with a real big time jump. So far I was only able to reproduce this with the vsyscall gettimeofday implementation, but in theory this might be observable with the syscall based version as well. CPU 0 updates the clock source variables under xtime/vyscall lock and CPU1, where the TSC is slighty behind CPU0, is reading the time right after the seqlock was unlocked. The clocksource reference data was updated with the TSC from CPU0 and the value which is read from TSC on CPU1 is less than the reference data. This results in a huge delta value due to the unsigned subtraction of the TSC value and the reference value. This algorithm can not be changed due to the support of wrapping clock sources like pm timer. The huge delta is converted to nanoseconds and added to xtime, which is then observable by the caller. The next gettimeofday call on CPU1 will show the correct time again as now the TSC has advanced above the reference value. To prevent this TSC specific wreckage we need to compare the TSC value against the reference value and return the latter when it is larger than the actual TSC value. I pondered to mark the TSC unstable when the readout is smaller than the reference value, but this would render an otherwise good and fast clocksource unusable without a real good reason. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: set_cyc2ns_scale() remove prev scaleIngo Molnar
Peter Zijlstra pointed out that it's unused. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-07x86: fix call to set_cyc2ns_scale() from time_cpufreq_notifier()Karsten Wiese
In time_cpufreq_notifier() the cpu id to act upon is held in freq->cpu. Use it instead of smp_processor_id() in the call to set_cyc2ns_scale(). This makes the preempt_*able() unnecessary and lets set_cyc2ns_scale() update the intended cpu's cyc2ns. Related mail/thread: http://lkml.org/lkml/2007/12/7/130 Signed-off-by: Karsten Wiese <fzu@wemgehoertderstaat.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-07revert "x86: tsc prevent time going backwards"Ingo Molnar
revert: | commit 47001d603375f857a7fab0e9c095d964a1ea0039 | Author: Thomas Gleixner <tglx@linutronix.de> | Date: Tue Apr 1 19:45:18 2008 +0200 | | x86: tsc prevent time going backwards it has been identified to cause suspend regression - and the commit fixes a longstanding bug that existed before 2.6.25 was opened - so it can wait some more until the effects are better understood. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-04x86: tsc prevent time going backwardsThomas Gleixner
We already catch most of the TSC problems by sanity checks, but there is a subtle bug which has been in the code for ever. This can cause time jumps in the range of hours. This was reported in: http://lkml.org/lkml/2007/8/23/96 and http://lkml.org/lkml/2008/3/31/23 I was able to reproduce the problem with a gettimeofday loop test on a dual core and a quad core machine which both have sychronized TSCs. The TSCs seems not to be perfectly in sync though, but the kernel is not able to detect the slight delta in the sync check. Still there exists an extremly small window where this delta can be observed with a real big time jump. So far I was only able to reproduce this with the vsyscall gettimeofday implementation, but in theory this might be observable with the syscall based version as well. CPU 0 updates the clock source variables under xtime/vyscall lock and CPU1, where the TSC is slighty behind CPU0, is reading the time right after the seqlock was unlocked. The clocksource reference data was updated with the TSC from CPU0 and the value which is read from TSC on CPU1 is less than the reference data. This results in a huge delta value due to the unsigned subtraction of the TSC value and the reference value. This algorithm can not be changed due to the support of wrapping clock sources like pm timer. The huge delta is converted to nanoseconds and added to xtime, which is then observable by the caller. The next gettimeofday call on CPU1 will show the correct time again as now the TSC has advanced above the reference value. To prevent this TSC specific wreckage we need to compare the TSC value against the reference value and return the latter when it is larger than the actual TSC value. I pondered to mark the TSC unstable when the readout is smaller than the reference value, but this would render an otherwise good and fast clocksource unusable without a real good reason. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-30x86: export check_tsc_unstableGlauber de Oliveira Costa
Exporrt check_tsc_unstable function as GPL symbol. lguest is a user of it. Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: remove explicit C3 TSC check on 64bitAndi Kleen
Trust the ACPI code to disable TSC instead when C3 is used. AMD Fam10h does not disable TSC in any C states so the check was incorrect there anyways after the change to handle this like Intel on AMD too. This allows to use the TSC when C3 is disabled in software (acpi.max_c_state=2), but the BIOS supports it anyways. Match i386 behaviour. Cc: lenb@kernel.org Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: allow TSC clock source on AMD Fam10h and some cleanupAndi Kleen
After a lot of discussions with AMD it turns out that TSC on Fam10h CPUs is synchronized when the CONSTANT_TSC cpuid bit is set. Or rather that if there are ever systems where that is not true it would be their BIOS' task to disable the bit. So finally use TSC gettimeofday on Fam10h by default. Or rather it is always used now on CPUs where the AMD specific CONSTANT_TSC bit is set. This gives a nice speed bost for gettimeofday() on these systems which tends to be by far the most common v/syscall. On a Fam10h system here TSC gtod uses about 20% of the CPU time of acpi_pm based gtod(). This was measured on 32bit, on 64bit it is even better because TSC gtod() can use a vsyscall and stay in ring 3, which acpi_pm doesn't. The Intel check simply checks for CONSTANT_TSC too without hardcoding Intel vendor. This is equivalent on 64bit because all 64bit capable Intel CPUs will have CONSTANT_TSC set. On Intel there is no CPU supplied CONSTANT_TSC bit currently, but we synthesize one based on hardcoded knowledge which steppings have p-state invariant TSC. So the new logic is now: On CPUs which have the AMD specific CONSTANT_TSC bit set or on Intel CPUs which are new enough to be known to have p-state invariant TSC always use TSC based gettimeofday() Cc: lenb@kernel.org Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: remove get_cycles_syncAndi Kleen
rdtsc is now speculation-safe, so no need for the sync variants of the APIs. [ mingo@elte.hu: removed the nsec_barrier() complication. ] Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: split get_cycles_syncGlauber de Oliveira Costa
This patch splits get_cycles_sync() into __get_cycles_sync(), and the rdtscll part. Paravirt guests cannot issue rdtscl directly, as it involves a function call in vdso area. So, using the __get_cycles_sync() base, we introduce vget_cycles_sync, which then calls the native version of rdtscll. Ideally, however, a guest should define its own clocksource, together with a vread function Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: allow sched clock to be overridden by paravirtGlauber de Oliveira Costa
This patch turns the sched_clock into native_sched_clock. sched clock becomes a weak symbol, which can then give its place to a paravirt definition. Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: scale cyc_2_nsec according to CPU frequencyGuillaume Chazarain
scale the sched_clock() cyc_2_nsec scaling factor according to CPU frequency changes. [ mingo@elte.hu: simplified it and fixed it for SMP. ] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-19x86: convert cpuinfo_x86 array to a per_cpu arrayMike Travis
cpu_data is currently an array defined using NR_CPUS. This means that we overallocate since we will rarely really use maximum configured cpus. When NR_CPU count is raised to 4096 the size of cpu_data becomes 3,145,728 bytes. These changes were adopted from the sparc64 (and ia64) code. An additional field was added to cpuinfo_x86 to be a non-ambiguous cpu index. This corresponds to the index into a cpumask_t as well as the per_cpu index. It's used in various places like show_cpuinfo(). cpu_data is defined to be the boot_cpu_data structure for the NON-SMP case. Signed-off-by: Mike Travis <travis@sgi.com> Acked-by: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Dmitry Torokhov <dtor@mail.ru> Cc: "Antonino A. Daplas" <adaplas@pol.net> Cc: Mark M. Hoffman <mhoffman@lightlink.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-12x86: unify timex.h variantsThomas Gleixner
Combine the timex.h variants and move the TSC related code into tsc.h. Move the set_cyc2ns_scale() call into the tsc calibraction code, where it belongs. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2007-10-12x86_64: Consolidate tsc calibrationThomas Gleixner
Move the TSC calibration code to tsc.c. Reimplement it so the pm timer can be used as a reference as well. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2007-10-11x86_64: move kernelThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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