Hi Dong,
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of WangDong
> Sent: Sunday, June 28, 2015 4:23 PM
> To: dev at dpdk.org
> Subject: [dpdk-dev] [PATCH 1/2] eal:Introduce rte_dma_wmb/rte_dma_rmb.
>
> These macro can be used to replace current PMD's compiler memory barrier
> (volatile varible) and rte_wmb.
> In x86, they implement to compiler memory barrier.
> In power, they implement to processor memory barrier.
>
> ---
> .../common/include/arch/ppc_64/rte_atomic.h | 4 ++++
> .../common/include/arch/x86/rte_atomic.h | 4 ++++
> lib/librte_eal/common/include/generic/rte_atomic.h | 25
> ++++++++++++++++++++++
> 3 files changed, 33 insertions(+)
>
> diff --git a/lib/librte_eal/common/include/arch/ppc_64/rte_atomic.h
> b/lib/librte_eal/common/include/arch/ppc_64/rte_atomic.h
> index fb7af2b..8f4129d 100644
> --- a/lib/librte_eal/common/include/arch/ppc_64/rte_atomic.h
> +++ b/lib/librte_eal/common/include/arch/ppc_64/rte_atomic.h
> @@ -72,6 +72,10 @@ extern "C" {
> */
> #define rte_rmb() {asm volatile("sync" : : : "memory"); }
>
> +#define rte_dma_wmb() {asm volatile("sync" : : : "memory"); }
> +
> +#define rte_dma_rmb() {asm volatile("sync" : : : "memory");
As a nit, probably better:
+#define rte_dma_wmb() rte_rmb()
+#define rte_dma_rmb() rte_wmb()
Here?
Konstantin
> +
> /*------------------------- 16 bit atomic operations
> -------------------------*/
> /* To be compatible with Power7, use GCC built-in functions for 16 bit
> * operations */
> diff --git a/lib/librte_eal/common/include/arch/x86/rte_atomic.h
> b/lib/librte_eal/common/include/arch/x86/rte_atomic.h
> index e93e8ee..7cfbe8f 100644
> --- a/lib/librte_eal/common/include/arch/x86/rte_atomic.h
> +++ b/lib/librte_eal/common/include/arch/x86/rte_atomic.h
> @@ -53,6 +53,10 @@ extern "C" {
>
> #define rte_rmb() _mm_lfence()
>
> +#define rte_dma_wmb() rte_compiler_barrier()
> +
> +#define rte_dma_rmb() rte_compiler_barrier()
> +
> /*------------------------- 16 bit atomic operations
> -------------------------*/
>
> #ifndef RTE_FORCE_INTRINSICS
> diff --git a/lib/librte_eal/common/include/generic/rte_atomic.h
> b/lib/librte_eal/common/include/generic/rte_atomic.h
> index 6c7581a..a51eeee 100644
> --- a/lib/librte_eal/common/include/generic/rte_atomic.h
> +++ b/lib/librte_eal/common/include/generic/rte_atomic.h
> @@ -72,6 +72,31 @@ static inline void rte_wmb(void);
> */
> static inline void rte_rmb(void);
>
> +/**
> + * Write memory barrier for DMA.
> + *
> + * Be used in PMD, unlike rte_wmb() which use processor memory barrier,
> + * this memory barrier focus on performance, if compiler memory barrier
> + * is sufficient for guarantee memory ordering, this function will
> + * use compiler memory barrier.
> + *
> + * This function is architecture dependent.
> + */
> +static inline void rte_dma_wmb(void);
> +
> +/**
> + * Read memory barrier for DMA.
> + *
> + * Be used in PMD, unlike rte_rmb() which use processor memory barrier,
> + * this memory barrier focus on performance, if compiler memory barrier
> + * is sufficient for guarantee memory ordering, this function will
> + * use compiler memory barrier.
> + *
> + * This function is architecture dependent.
> + */
> +static inline void rte_dma_rmb(void);
> +
> +
> #endif /* __DOXYGEN__ */
>
> /**
> --
> 2.1.0
