search for: 6440d5943c00

There is no need for rmb(), this allows faster lwsync here. Signed-off-by: Nicholas Piggin <npiggin at gmail.com> --- arch/powerpc/lib/locks.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c index 6440d5943c00..47a530de733e 100644 --- a/arch/powerpc/lib/locks.c +++ b/arch/powerpc/lib/locks.c @@ -30,7 +30,7 @@ void splpar_spin_yield(arch_spinlock_t *lock) yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count); if ((yield_count & 1) == 0) return; /* virtual cpu is currently running */ - r...

...hared_processor(void) -{ -#ifdef CONFIG_PPC_SPLPAR - return static_branch_unlikely(&shared_processor); -#else - return false; -#endif -} - static inline void spin_yield(arch_spinlock_t *lock) { if (is_shared_processor()) diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c index 6440d5943c00..04165b7a163f 100644 --- a/arch/powerpc/lib/locks.c +++ b/arch/powerpc/lib/locks.c @@ -27,14 +27,14 @@ void splpar_spin_yield(arch_spinlock_t *lock) return; holder_cpu = lock_value & 0xffff; BUG_ON(holder_cpu >= NR_CPUS); - yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count);...

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

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

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