search for: hmt_medium

...ld(lock); + else + barrier(); +} + +static inline void arch_spin_lock(arch_spinlock_t *lock) +{ + while (1) { + if (likely(__arch_spin_trylock(lock) == 0)) + break; + do { + HMT_low(); + if (is_shared_processor()) + splpar_spin_yield(lock); + } while (unlikely(lock->slock != 0)); + HMT_medium(); + } +} + +static inline +void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) +{ + unsigned long flags_dis; + + while (1) { + if (likely(__arch_spin_trylock(lock) == 0)) + break; + local_save_flags(flags_dis); + local_irq_restore(flags); + do { + HMT_low(); + if (is_sh...

This series adds an option to use queued spinlocks for powerpc, and makes it the default for the Book3S-64 subarch. This effort starts with the generic code so it's very simple but still very performant. There are optimisations that can be made to slowpaths, but I think it's better to attack those incrementally if/when we find things, and try to add the improvements to generic code as

v2 is updated to account for feedback from Will, Peter, and Waiman (thank you), and trims off a couple of RFC and unrelated patches. Thanks, Nick Nicholas Piggin (6): powerpc/powernv: must include hvcall.h to get PAPR defines powerpc/pseries: move some PAPR paravirt functions to their own file powerpc: move spinlock implementation to simple_spinlock powerpc/64s: implement queued

Updated with everybody's feedback (thanks all), and more performance results. What I've found is I might have been measuring the worst load point for the paravirt case, and by looking at a range of loads it's clear that queued spinlocks are overall better even on PV, doubly so when you look at the generally much improved worst case latencies. I have defaulted it to N even though

v3 is updated to use __pv_queued_spin_unlock, noticed by Waiman (thank you). Thanks, Nick Nicholas Piggin (6): powerpc/powernv: must include hvcall.h to get PAPR defines powerpc/pseries: move some PAPR paravirt functions to their own file powerpc: move spinlock implementation to simple_spinlock powerpc/64s: implement queued spinlocks and rwlocks powerpc/pseries: implement paravirt

v3 is updated to use __pv_queued_spin_unlock, noticed by Waiman (thank you). Thanks, Nick Nicholas Piggin (6): powerpc/powernv: must include hvcall.h to get PAPR defines powerpc/pseries: move some PAPR paravirt functions to their own file powerpc: move spinlock implementation to simple_spinlock powerpc/64s: implement queued spinlocks and rwlocks powerpc/pseries: implement paravirt

...the License, or + * (at your option) any later version. + */ + +#include <linux/spinlock.h> + +static void __native_queued_spin_unlock(struct qspinlock *lock) +{ + native_queued_spin_unlock(lock); +} + +static void __pv_wait(u8 *ptr, u8 val, int cpu) +{ + HMT_low(); + __spin_yield_cpu(cpu); + HMT_medium(); +} + +static void __pv_kick(int cpu) +{ + __spin_wake_cpu(cpu); +} + +struct pv_lock_ops pv_lock_op = { + .lock = native_queued_spin_lock_slowpath, + .unlock = __native_queued_spin_unlock, + .wait = NULL, + .kick = NULL, +}; +EXPORT_SYMBOL(pv_lock_op); + +void __init pv_lock_init(void) +{ + if (...

...ic void __native_queued_spin_unlock(struct qspinlock *lock) +{ + native_queued_spin_unlock(lock); +} + +static void __native_wait(u8 *ptr, u8 val, int cpu) +{ +} + +static void __native_kick(int cpu) +{ +} + +static void __pv_wait(u8 *ptr, u8 val, int cpu) +{ + HMT_low(); + __spin_yield_cpu(cpu); + HMT_medium(); +} + +static void __pv_kick(int cpu) +{ + __spin_wake_cpu(cpu); +} + +struct pv_lock_ops pv_lock_op = { + .lock = native_queued_spin_lock_slowpath, + .unlock = __native_queued_spin_unlock, + .wait = __native_wait, + .kick = __native_kick, +}; +EXPORT_SYMBOL(pv_lock_op); + +void __init pv_lock_in...

...ic void __native_queued_spin_unlock(struct qspinlock *lock) +{ + native_queued_spin_unlock(lock); +} + +static void __native_wait(u8 *ptr, u8 val, int cpu) +{ +} + +static void __native_kick(int cpu) +{ +} + +static void __pv_wait(u8 *ptr, u8 val, int cpu) +{ + HMT_low(); + __spin_yield_cpu(cpu); + HMT_medium(); +} + +static void __pv_kick(int cpu) +{ + __spin_wake_cpu(cpu); +} + +struct pv_lock_ops pv_lock_op = { + .lock = native_queued_spin_lock_slowpath, + .unlock = __native_queued_spin_unlock, + .wait = __native_wait, + .kick = __native_kick, +}; +EXPORT_SYMBOL(pv_lock_op); + +void __init pv_lock_in...

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

...ic void __native_queued_spin_unlock(struct qspinlock *lock) +{ + native_queued_spin_unlock(lock); +} + +static void __native_wait(u8 *ptr, u8 val, int cpu) +{ +} + +static void __native_kick(int cpu) +{ +} + +static void __pv_wait(u8 *ptr, u8 val, int cpu) +{ + HMT_low(); + __spin_yield_cpu(cpu); + HMT_medium(); +} + +static void __pv_kick(int cpu) +{ + __spin_wake_cpu(cpu); +} + +struct pv_lock_ops pv_lock_op = { + .lock = native_queued_spin_lock_slowpath, + .unlock = __native_queued_spin_unlock, + .wait = __native_wait, + .kick = __native_kick, +}; +EXPORT_SYMBOL(pv_lock_op); + +void __init pv_lock_in...

...ic void __native_queued_spin_unlock(struct qspinlock *lock) +{ + native_queued_spin_unlock(lock); +} + +static void __native_wait(u8 *ptr, u8 val, int cpu) +{ +} + +static void __native_kick(int cpu) +{ +} + +static void __pv_wait(u8 *ptr, u8 val, int cpu) +{ + HMT_low(); + __spin_yield_cpu(cpu); + HMT_medium(); +} + +static void __pv_kick(int cpu) +{ + __spin_wake_cpu(cpu); +} + +struct pv_lock_ops pv_lock_op = { + .lock = native_queued_spin_lock_slowpath, + .unlock = __native_queued_spin_unlock, + .wait = __native_wait, + .kick = __native_kick, +}; +EXPORT_SYMBOL(pv_lock_op); + +void __init pv_lock_in...

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 |

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

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