[dpdk-dev] [PATCH v5 3/8] eal: add the APIs to wait until equal
Jerin Jacob
jerinjacobk at gmail.com
Thu Sep 12 18:11:48 CEST 2019
On Thu, Sep 12, 2019 at 4:56 PM Gavin Hu <gavin.hu at arm.com> wrote:
>
> The rte_wait_until_equalxx APIs abstract the functionality of 'polling
> for a memory location to become equal to a given value'.
>
> Signed-off-by: Gavin Hu <gavin.hu at arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
> Reviewed-by: Steve Capper <steve.capper at arm.com>
> Reviewed-by: Ola Liljedahl <ola.liljedahl at arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli at arm.com>
> Reviewed-by: Phil Yang <phil.yang at arm.com>
> Acked-by: Pavan Nikhilesh <pbhagavatula at marvell.com>
> ---
> .../common/include/arch/arm/rte_pause_64.h | 30 +++++++
> lib/librte_eal/common/include/generic/rte_pause.h | 98 +++++++++++++++++++++-
> 2 files changed, 127 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_eal/common/include/arch/arm/rte_pause_64.h b/lib/librte_eal/common/include/arch/arm/rte_pause_64.h
> index 93895d3..dabde17 100644
> --- a/lib/librte_eal/common/include/arch/arm/rte_pause_64.h
> +++ b/lib/librte_eal/common/include/arch/arm/rte_pause_64.h
> @@ -1,5 +1,6 @@
> /* SPDX-License-Identifier: BSD-3-Clause
> * Copyright(c) 2017 Cavium, Inc
> + * Copyright(c) 2019 Arm Limited
> */
>
> #ifndef _RTE_PAUSE_ARM64_H_
> @@ -17,6 +18,35 @@ static inline void rte_pause(void)
> asm volatile("yield" ::: "memory");
> }
>
> +#ifdef RTE_ARM_USE_WFE
> +#define __WAIT_UNTIL_EQUAL(name, asm_op, wide, type) \
> +static __rte_always_inline void \
> +rte_wait_until_equal_##name(volatile type * addr, type expected) \
> +{ \
> + type tmp; \
> + asm volatile( \
> + #asm_op " %" #wide "[tmp], %[addr]\n" \
> + "cmp %" #wide "[tmp], %" #wide "[expected]\n" \
> + "b.eq 2f\n" \
> + "sevl\n" \
> + "1: wfe\n" \
> + #asm_op " %" #wide "[tmp], %[addr]\n" \
> + "cmp %" #wide "[tmp], %" #wide "[expected]\n" \
> + "bne 1b\n" \
> + "2:\n" \
> + : [tmp] "=&r" (tmp) \
> + : [addr] "Q"(*addr), [expected] "r"(expected) \
> + : "cc", "memory"); \
> +}
> +/* Wait for *addr to be updated with expected value */
> +__WAIT_UNTIL_EQUAL(relaxed_16, ldxrh, w, uint16_t)
> +__WAIT_UNTIL_EQUAL(acquire_16, ldaxrh, w, uint16_t)
> +__WAIT_UNTIL_EQUAL(relaxed_32, ldxr, w, uint32_t)
> +__WAIT_UNTIL_EQUAL(acquire_32, ldaxr, w, uint32_t)
> +__WAIT_UNTIL_EQUAL(relaxed_64, ldxr, x, uint64_t)
> +__WAIT_UNTIL_EQUAL(acquire_64, ldaxr, x, uint64_t)
> +#endif
Looks good.
> +
> #ifdef __cplusplus
> }
> #endif
> diff --git a/lib/librte_eal/common/include/generic/rte_pause.h b/lib/librte_eal/common/include/generic/rte_pause.h
> index 52bd4db..dfa6a53 100644
> --- a/lib/librte_eal/common/include/generic/rte_pause.h
> +++ b/lib/librte_eal/common/include/generic/rte_pause.h
> @@ -1,10 +1,10 @@
> /* SPDX-License-Identifier: BSD-3-Clause
> * Copyright(c) 2017 Cavium, Inc
> + * Copyright(c) 2019 Arm Limited
> */
>
> #ifndef _RTE_PAUSE_H_
> #define _RTE_PAUSE_H_
> -
Unwanted change.
> /**
> * @file
> *
> @@ -12,6 +12,10 @@
> *
> */
>
> +#include <stdint.h>
> +#include <rte_common.h>
> +#include <rte_atomic.h>
> +
> /**
> * Pause CPU execution for a short while
> *
> @@ -20,4 +24,96 @@
> */
> static inline void rte_pause(void);
>
> +/**
> + * Wait for *addr to be updated with expected value
IMO, We need to mention relaxed attribute also in the comment.
> + *
> + * @param addr
> + * A pointer to the memory location.
> + * @param expected
> + * An expected value to be in the memory location.
> + */
> +__rte_always_inline
> +static void
> +rte_wait_until_equal_relaxed_16(volatile uint16_t *addr, uint16_t expected);
> +
> +/**
> + * Wait for *addr to be updated with expected value
> + *
> + * @param addr
> + * A pointer to the memory location.
> + * @param expected
> + * An expected value to be in the memory location.
> + */
> +__rte_always_inline
> +static void
> +rte_wait_until_equal_acquire_64(volatile uint64_t *addr, uint64_t expected);
> +
> +#if !defined(RTE_ARM_USE_WFE)
Looks like there is a side effect as meson's build/rte_build_config.h
comes as below
#define RTE_ARM_USE_WFE 0
So actually it is defined.
> +#define __WAIT_UNTIL_EQUAL(op_name, size, type, memorder) \
> +__rte_always_inline \
> +static void \
> +rte_wait_until_equal_##op_name##_##size(volatile type *addr, \
> + type expected) \
> +{ \
> + while (__atomic_load_n(addr, memorder) != expected) \
> + rte_pause(); \
> +}
> +
> +/* Wait for *addr to be updated with expected value */
> +__WAIT_UNTIL_EQUAL(relaxed, 16, uint16_t, __ATOMIC_RELAXED)
> +__WAIT_UNTIL_EQUAL(acquire, 16, uint16_t, __ATOMIC_ACQUIRE)
> +__WAIT_UNTIL_EQUAL(relaxed, 32, uint32_t, __ATOMIC_RELAXED)
> +__WAIT_UNTIL_EQUAL(acquire, 32, uint32_t, __ATOMIC_ACQUIRE)
> +__WAIT_UNTIL_EQUAL(relaxed, 64, uint64_t, __ATOMIC_RELAXED)
> +__WAIT_UNTIL_EQUAL(acquire, 64, uint64_t, __ATOMIC_ACQUIRE)
> +#endif /* RTE_ARM_USE_WFE */
> +
> #endif /* _RTE_PAUSE_H_ */
> --
> 2.7.4
>
More information about the dev
mailing list