On 26 November 2015 at 09:56, Savolainen, Petri (Nokia - FI/Espoo) < petri.savolai...@nokia.com> wrote:
> ping. > > > -----Original Message----- > > From: lng-odp [mailto:lng-odp-boun...@lists.linaro.org] On Behalf Of EXT > > Petri Savolainen > > Sent: Thursday, November 12, 2015 10:30 AM > > To: lng-odp@lists.linaro.org > > Subject: [lng-odp] [API-NEXT PATCH v3] api: atomic: added > > atomic_lock_free_u64 > > > > Platforms may support some uint64 operations lock-free and > > others not. For example, inc_64 can be natively supported but > > cas_64 (or max_64/min_64) not. User may be able to switch to > > 32 bit variables when a 64 bit operation uses locks. The same > > atomic operation struture could be used for platform init to guide > > lock vs. lock-free implementation (e.g. if cas_64 is never > > called, inc_64 can be lock-free). > > > > Signed-off-by: Petri Savolainen <petri.savolai...@nokia.com> > Reviewed-by: Ola Liljedahl <ola.liljed...@linaro.org> > > --- > > include/odp/api/atomic.h | 48 > > +++++++++++++++++++++++++++++++++++++ > > platform/linux-generic/Makefile.am | 1 + > > platform/linux-generic/odp_atomic.c | 24 +++++++++++++++++++ > > 3 files changed, 73 insertions(+) > > create mode 100644 platform/linux-generic/odp_atomic.c > > > > diff --git a/include/odp/api/atomic.h b/include/odp/api/atomic.h > > index 316f13a..5e897c1 100644 > > --- a/include/odp/api/atomic.h > > +++ b/include/odp/api/atomic.h > > @@ -388,6 +388,54 @@ void odp_atomic_add_rls_u32(odp_atomic_u32_t *atom, > > uint32_t val); > > void odp_atomic_sub_rls_u32(odp_atomic_u32_t *atom, uint32_t val); > > > > /** > > + * Atomic operations > > + * > > + * Atomic operations listed in a bit field structure. > > + */ > > +typedef union odp_atomic_op_t { > > + /** Operation flags */ > > + struct { > > + uint32_t init : 1; /**< Init atomic variable */ > > + uint32_t load : 1; /**< Atomic load */ > > + uint32_t store : 1; /**< Atomic store */ > > + uint32_t fetch_add : 1; /**< Atomic fetch and add */ > > + uint32_t add : 1; /**< Atomic add */ > > + uint32_t fetch_sub : 1; /**< Atomic fetch and substract */ > > + uint32_t sub : 1; /**< Atomic substract */ > > + uint32_t fetch_inc : 1; /**< Atomic fetch and increment */ > > + uint32_t inc : 1; /**< Atomic increment */ > > + uint32_t fetch_dec : 1; /**< Atomic fetch and decrement */ > > + uint32_t dec : 1; /**< Atomic decrement */ > > + uint32_t min : 1; /**< Atomic minimum */ > > + uint32_t max : 1; /**< Atomic maximum */ > > + uint32_t cas : 1; /**< Atomic compare and swap */ > > + } op; > > + > > + /** All bits of the bit field structure. > > + * Operation flag mapping is architecture specific. This field can > > be > > + * used to set/clear all flags, or bitwise operations over the > > entire > > + * structure. */ > > + uint32_t all_bits; > > +} odp_atomic_op_t; > > + > > +/** > > + * Query which atomic uint64 operations are lock-free > > + * > > + * Lock-free implementations have higher performance and scale better > > than > > + * implementations using locks. User can decide to use e.g. uint32 > atomic > > + * variables instead of uint64 to optimize performance on platforms that > > + * implement a performance critical operation using locks. > > + * > > + * @param atomic_op Pointer to atomic operation structure for storing > > + * operation flags. All bits are initialized to zero > > during > > + * the operation. The parameter is ignored when NULL. > > + * @retval 0 None of the operations are lock-free > > + * @retval 1 Some of the operations are lock-free > > + * @retval 2 All operations are lock-free > > + */ > > +int odp_atomic_lock_free_u64(odp_atomic_op_t *atomic_op); > > + > > +/** > > * @} > > */ > > > > diff --git a/platform/linux-generic/Makefile.am b/platform/linux- > > generic/Makefile.am > > index a6b6029..0b7234e 100644 > > --- a/platform/linux-generic/Makefile.am > > +++ b/platform/linux-generic/Makefile.am > > @@ -151,6 +151,7 @@ noinst_HEADERS = \ > > ${srcdir}/Makefile.inc > > > > __LIB__libodp_la_SOURCES = \ > > + odp_atomic.c \ > > odp_barrier.c \ > > odp_buffer.c \ > > odp_classification.c \ > > diff --git a/platform/linux-generic/odp_atomic.c b/platform/linux- > > generic/odp_atomic.c > > new file mode 100644 > > index 0000000..996d09a > > --- /dev/null > > +++ b/platform/linux-generic/odp_atomic.c > > @@ -0,0 +1,24 @@ > > +/* Copyright (c) 2015, Linaro Limited > > + * All rights reserved. > > + * > > + * SPDX-License-Identifier: BSD-3-Clause > > + */ > > + > > +#include <odp/atomic.h> > > + > > +int odp_atomic_lock_free_u64(odp_atomic_op_t *atomic_op) > > +{ > > +#if __GCC_ATOMIC_LLONG_LOCK_FREE < 2 > > + /* All operations have locks */ > > + if (atomic_op) > > + atomic_op->all_bits = 0; > > + > > + return 0; > > +#else > > + /* All operations are lock-free */ > > + if (atomic_op) > > + atomic_op->all_bits = ~((uint32_t)0); > > + > > + return 2; > > +#endif > > +} > > -- > > 2.6.2 > > > > _______________________________________________ > > lng-odp mailing list > > lng-odp@lists.linaro.org > > https://lists.linaro.org/mailman/listinfo/lng-odp > _______________________________________________ > lng-odp mailing list > lng-odp@lists.linaro.org > https://lists.linaro.org/mailman/listinfo/lng-odp >
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