search for: pv_lock

...this, I think I found the issue. However, if that is true, it seems rather lucky if pv spinlocks in HVM worked for anybody. The xen_hvm_smp_init() call will change the smp_ops hooks. One of which is smp_prepare_cpus. This is done in start_kernel and at this point in time, there is no change to the pv_lock_ops and they point to the ticket versions. Later in start_kernel, check_bugs is called and part of that takes the pv_lock_ops and patches the kernel with the correct jumps. _After_ that, the kernel_init is called and that in turn does the smp_prepare_cpus which now changes the pv_lock_ops again, *b...

...> +====================================== >> + >> +KVM/arm64 provids some hypervisor service calls to support a paravirtualized >> +guest obtaining the vcpu is currently running or not. >> + >> +Two new SMCCC compatible hypercalls are defined: >> + >> +* PV_LOCK_FEATURES: 0xC5000040 >> +* PV_LOCK_PREEMPTED: 0xC5000041 > > These values are in the "Standard Hypervisor Service Calls" section of > SMCCC - so is there a document that describes this features such that > other OSes or hypervisors can implement it? I'm also not...

As we need let pv-qspinlock-kernel run on all environment which might have no powervm, we should runtime choose which qspinlock version to use. The default pv-qspinlock use native version. pv_lock initialization should be done in bootstage with irq disabled. And if possible, restore pv_lock_ops callbacks to pv version. Signed-off-by: Pan Xinhui <xinhui.pan at linux.vnet.ibm.com> --- arch/powerpc/include/asm/qspinlock.h | 17 +++++++++ arch/powerpc/include/asm/qspinlock_...

...l Overhead | 3913363.1 lps | 3883287.8 lps ----------------------------------------+-------------------+------------------ System Benchmarks Index Score | 1835.1 | 1327.6 Zengruan Ye (5): KVM: arm64: Document PV-lock interface KVM: arm64: Implement PV_LOCK_FEATURES call KVM: arm64: Support pvlock preempted via shared structure KVM: arm64: Add interface to support vcpu preempted check KVM: arm64: Support the vcpu preemption check Documentation/virt/kvm/arm/pvlock.rst | 31 +++++++++ arch/arm/include/asm/kvm_host.h | 13 ++++ arch/arm64...

...l Overhead | 3913363.1 lps | 3883287.8 lps ----------------------------------------+-------------------+------------------ System Benchmarks Index Score | 1835.1 | 1327.6 Zengruan Ye (5): KVM: arm64: Document PV-lock interface KVM: arm64: Implement PV_LOCK_FEATURES call KVM: arm64: Support pvlock preempted via shared structure KVM: arm64: Add interface to support vcpu preempted check KVM: arm64: Support the vcpu preemption check Documentation/virt/kvm/arm/pvlock.rst | 31 +++++++++ arch/arm/include/asm/kvm_host.h | 13 ++++ arch/arm64...

change fome v1: separate into 6 pathes from one patch some minor code changes. benchmark test results are below. run 3 tests on pseries IBM,8408-E8E with 32cpus, 64GB memory perf bench futex hash perf bench futex lock-pi perf record -advRT || perf bench sched messaging -g 1000 || perf report summary: _____test________________spinlcok______________pv-qspinlcok_____ |futex hash | 556370 ops |

change fome v1: separate into 6 pathes from one patch some minor code changes. benchmark test results are below. run 3 tests on pseries IBM,8408-E8E with 32cpus, 64GB memory perf bench futex hash perf bench futex lock-pi perf record -advRT || perf bench sched messaging -g 1000 || perf report summary: _____test________________spinlcok______________pv-qspinlcok_____ |futex hash | 556370 ops |

change from v2: __spin_yeild_cpu() will yield slices to lpar if target cpu is running. remove unnecessary rmb() in __spin_yield/wake_cpu. __pv_wait() will check the *ptr == val. some commit message change change fome v1: separate into 6 pathes from one patch some minor code changes. I do several tests on pseries IBM,8408-E8E with 32cpus, 64GB memory. benchmark test results are below. 2

change from v2: __spin_yeild_cpu() will yield slices to lpar if target cpu is running. remove unnecessary rmb() in __spin_yield/wake_cpu. __pv_wait() will check the *ptr == val. some commit message change change fome v1: separate into 6 pathes from one patch some minor code changes. I do several tests on pseries IBM,8408-E8E with 32cpus, 64GB memory. benchmark test results are below. 2

change from v4: BUG FIX. thanks boqun reporting this issue. struct __qspinlock has different layout in bigendian mahcine. native_queued_spin_unlock() may write value to a wrong address. now fix it. sorry for not even doing a test on bigendian machine before!!! change from v3: a big change in [PATCH v4 4/6] pv-qspinlock: powerpc support pv-qspinlock no other patch changed. and the patch

change from v4: BUG FIX. thanks boqun reporting this issue. struct __qspinlock has different layout in bigendian mahcine. native_queued_spin_unlock() may write value to a wrong address. now fix it. sorry for not even doing a test on bigendian machine before!!! change from v3: a big change in [PATCH v4 4/6] pv-qspinlock: powerpc support pv-qspinlock no other patch changed. and the patch

From: root <root at ltcalpine2-lp13.aus.stglabs.ibm.com> change from v4: BUG FIX. thanks boqun reporting this issue. struct __qspinlock has different layout in bigendian mahcine. native_queued_spin_unlock() may write value to a wrong address. now fix it. change from v3: a big change in [PATCH v4 4/6] pv-qspinlock: powerpc support pv-qspinlock no other patch changed. and the patch

From: root <root at ltcalpine2-lp13.aus.stglabs.ibm.com> change from v4: BUG FIX. thanks boqun reporting this issue. struct __qspinlock has different layout in bigendian mahcine. native_queued_spin_unlock() may write value to a wrong address. now fix it. change from v3: a big change in [PATCH v4 4/6] pv-qspinlock: powerpc support pv-qspinlock no other patch changed. and the patch

Hi All, this is the fairlock patchset. You can apply them and build successfully. patches are based on linux-next qspinlock can avoid waiter starved issue. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. v8 -> v9: mv qspinlocm config entry to

Hi All, this is the fairlock patchset. You can apply them and build successfully. patches are based on linux-next qspinlock can avoid waiter starved issue. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. v8 -> v9: mv qspinlocm config entry to

This patch set aims to support the vcpu_is_preempted() functionality under KVM/arm64, which allowing the guest to obtain the VCPU is currently running or not. This will enhance lock performance on overcommitted hosts (more runnable VCPUs than physical CPUs in the system) as doing busy waits for preempted VCPUs will hurt system performance far worse than early yielding. We have observed some

Hi All, this is the fairlock patchset. You can apply them and build successfully. patches are based on linux-next qspinlock can avoid waiter starved issue. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. v7 -> v8: add one patch to drop a function call

Hi All, this is the fairlock patchset. You can apply them and build successfully. patches are based on linux-next qspinlock can avoid waiter starved issue. It has about the same speed in single-thread and it can be much faster in high contention situations especially when the spinlock is embedded within the data structure to be protected. v7 -> v8: add one patch to drop a function call