kernel.git/arch/x86/kernel/tsc.c, branch linux-4.12.y

sched/clock, x86/perf: Fix "perf test tsc"

2017-03-23T06:31:49Z

People reported that commit: 5680d8094ffa ("sched/clock: Provide better clock continuity") broke "perf test tsc". That commit added another offset to the reported clock value; so take that into account when computing the provided offset values. Reported-by: Adrian Hunter Reported-by: Arnaldo Carvalho de Melo Tested-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 5680d8094ffa ("sched/clock: Provide better clock continuity") Signed-off-by: Ingo Molnar

x86/tsc: Fix ART for TSC_KNOWN_FREQ

2017-03-13T18:50:23Z

Subhransu reported that convert_art_to_tsc() isn't working for him. The ART to TSC relation is only set up for systems which use the refined TSC calibration. Systems with known TSC frequency (available via CPUID 15) are not using the refined calibration and therefor the ART to TSC relation is never established. Add the setup to the known frequency init path which skips ART calibration. The init code needs to be duplicated as for systems which use refined calibration the ART setup must be delayed until calibration has been done. The problem has been there since the ART support was introdduced, but only detected now because Subhransu tested the first time on hardware which has TSC frequency enumerated via CPUID 15. Note for stable: The conditional has changed from TSC_RELIABLE to TSC_KNOWN_FREQUENCY. [ tglx: Rewrote changelog and identified the proper 'Fixes' commit ] Fixes: f9677e0f8308 ("x86/tsc: Always Running Timer (ART) correlated clocksource") Reported-by: "Prusty, Subhransu S" Signed-off-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org Cc: christopher.s.hall@intel.com Cc: kevin.b.stanton@intel.com Cc: john.stultz@linaro.org Cc: akataria@vmware.com Link: http://lkml.kernel.org/r/20170313145712.GI3312@twins.programming.kicks-ass.net Signed-off-by: Thomas Gleixner

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-03-07T22:42:34Z

Pull scheduler fixes from Ingo Molnar: "A fix for KVM's scheduler clock which (erroneously) was always marked unstable, a fix for RT/DL load balancing, plus latency fixes" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/clock, x86/tsc: Rework the x86 'unstable' sched_clock() interface sched/core: Fix pick_next_task() for RT,DL sched/fair: Make select_idle_cpu() more aggressive

sched/clock, x86/tsc: Rework the x86 'unstable' sched_clock() interface

2017-03-02T07:50:49Z

Wanpeng Li reported that since the following commit: acb04058de49 ("sched/clock: Fix hotplug crash") ... KVM always runs with unstable sched-clock even though KVM's kvm_clock _is_ stable. The problem is that we've tied clear_sched_clock_stable() to the TSC state, and overlooked that sched_clock() is a paravirt function. Solve this by doing two things: - tie the sched_clock() stable state more clearly to the TSC stable state for the normal (!paravirt) case. - only call clear_sched_clock_stable() when we mark TSC unstable when we use native_sched_clock(). The first means we can actually run with stable sched_clock in more situations then before, which is good. And since commit: 12907fbb1a69 ("sched/clock, clocksource: Add optional cs::mark_unstable() method") ... this should be reliable. Since any detection of TSC fail now results in marking the TSC unstable. Reported-by: Wanpeng Li Signed-off-by: Peter Zijlstra (Intel) Cc: Borislav Petkov Cc: Linus Torvalds Cc: Mike Galbraith Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Fixes: acb04058de49 ("sched/clock: Fix hotplug crash") Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:27Z

We are going to split out of , which will have to be picked up from other headers and .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-02-20T20:52:55Z

Pull scheduler updates from Ingo Molnar: "The main changes in this (fairly busy) cycle were: - There was a class of scheduler bugs related to forgetting to update the rq-clock timestamp which can cause weird and hard to debug problems, so there's a new debug facility for this: which uncovered a whole lot of bugs which convinced us that we want to keep the debug facility. (Peter Zijlstra, Matt Fleming) - Various cputime related updates: eliminate cputime and use u64 nanoseconds directly, simplify and improve the arch interfaces, implement delayed accounting more widely, etc. - (Frederic Weisbecker) - Move code around for better structure plus cleanups (Ingo Molnar) - Move IO schedule accounting deeper into the scheduler plus related changes to improve the situation (Tejun Heo) - ... plus a round of sched/rt and sched/deadline fixes, plus other fixes, updats and cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (85 commits) sched/core: Remove unlikely() annotation from sched_move_task() sched/autogroup: Rename auto_group.[ch] to autogroup.[ch] sched/topology: Split out scheduler topology code from core.c into topology.c sched/core: Remove unnecessary #include headers sched/rq_clock: Consolidate the ordering of the rq_clock methods delayacct: Include sched/core: Clean up comments sched/rt: Show the 'sched_rr_timeslice' SCHED_RR timeslice tuning knob in milliseconds sched/clock: Add dummy clear_sched_clock_stable() stub function sched/cputime: Remove generic asm headers sched/cputime: Remove unused nsec_to_cputime() s390, sched/cputime: Remove unused cputime definitions powerpc, sched/cputime: Remove unused cputime definitions s390, sched/cputime: Make arch_cpu_idle_time() to return nsecs ia64, sched/cputime: Remove unused cputime definitions ia64: Convert vtime to use nsec units directly ia64, sched/cputime: Move the nsecs based cputime headers to the last arch using it sched/cputime: Remove jiffies based cputime sched/cputime, vtime: Return nsecs instead of cputime_t to account sched/cputime: Complete nsec conversion of tick based accounting ...

x86/tsc: Avoid the large time jump when sanitizing TSC ADJUST

2017-02-10T08:47:16Z

Olof reported that on a machine which has a BIOS wreckaged TSC the timestamps in dmesg are making a large jump because the TSC value is jumping forward after resetting the TSC ADJUST register to a sane value. This can be avoided by calling the TSC ADJUST saniziting function before initializing the per cpu sched clock machinery. That takes the offset into account and avoid the time jump. What cannot be avoided is that the 'Firmware Bug' warnings on the secondary CPUs are printed with the large time offsets because it would be too much effort and ugly hackery to print those warnings into a buffer and emit them after the adjustemt on the starting CPUs. It's a firmware bug and should be fixed in firmware. The weird timestamps are collateral damage and just illustrate the sillyness of the BIOS folks: [ 0.397445] smp: Bringing up secondary CPUs ... [ 0.402100] x86: Booting SMP configuration: [ 0.406343] .... node #0, CPUs: #1 [1265776479.930667] [Firmware Bug]: TSC ADJUST differs: Reference CPU0: -2978888639075328 CPU1: -2978888639183101 [1265776479.944664] TSC ADJUST synchronize: Reference CPU0: 0 CPU1: -2978888639183101 [ 0.508119] #2 [1265776480.032346] [Firmware Bug]: TSC ADJUST differs: Reference CPU0: -2978888639075328 CPU2: -2978888639183677 [1265776480.044192] TSC ADJUST synchronize: Reference CPU0: 0 CPU2: -2978888639183677 [ 0.607643] #3 [1265776480.131874] [Firmware Bug]: TSC ADJUST differs: Reference CPU0: -2978888639075328 CPU3: -2978888639184530 [1265776480.143720] TSC ADJUST synchronize: Reference CPU0: 0 CPU3: -2978888639184530 [ 0.707108] smp: Brought up 1 node, 4 CPUs [ 0.711271] smpboot: Total of 4 processors activated (21698.88 BogoMIPS) Reported-by: Olof Johansson Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20170209151231.411460506@linutronix.de Signed-off-by: Thomas Gleixner

Merge branch 'linus' into sched/core, to pick up fixes and refresh the branch

2017-02-01T08:12:25Z

Signed-off-by: Ingo Molnar

sched/clock, clocksource: Add optional cs::mark_unstable() method

2017-01-14T10:29:43Z

PeterZ reported that we'd fail to mark the TSC unstable when the clocksource watchdog finds it unsuitable. Allow a clocksource to run a custom action when its being marked unstable and hook up the TSC unstable code. Reported-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

x86/tsc: Add the Intel Denverton Processor to native_calibrate_tsc()

2017-01-14T08:30:37Z

The Intel Denverton microserver uses a 25 MHz TSC crystal, so we can derive its exact [*] TSC frequency using CPUID and some arithmetic, eg.: TSC: 1800 MHz (25000000 Hz * 216 / 3 / 1000000) [*] 'exact' is only as good as the crystal, which should be +/- 20ppm Signed-off-by: Len Brown Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/306899f94804aece6d8fa8b4223ede3b48dbb59c.1484287748.git.len.brown@intel.com Signed-off-by: Ingo Molnar