Re: [dpdk-dev] [PATCH v2 1/2] eal: add 128-bit cmpset (x86-64 only)

[Gavin Hu (Arm Technology China)]

> -----Original Message-----
> From: dev <dev-boun...@dpdk.org> On Behalf Of Gage Eads
> Sent: Wednesday, January 16, 2019 6:33 AM
> To: dev@dpdk.org
> Cc: olivier.m...@6wind.com; arybche...@solarflare.com;
> bruce.richard...@intel.com; konstantin.anan...@intel.com
> Subject: [dpdk-dev] [PATCH v2 1/2] eal: add 128-bit cmpset (x86-64 only)
>
> This operation can be used for non-blocking algorithms, such as a
> non-blocking stack or ring.
>
> Signed-off-by: Gage Eads <gage.e...@intel.com>
> ---
>  .../common/include/arch/x86/rte_atomic_64.h        | 22
> ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>
> diff --git a/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
> b/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
> index fd2ec9c53..34c2addf8 100644
> --- a/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
> +++ b/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
> @@ -34,6 +34,7 @@
>  /*
>   * Inspired from FreeBSD src/sys/amd64/include/atomic.h
>   * Copyright (c) 1998 Doug Rabson
> + * Copyright (c) 2019 Intel Corporation
>   * All rights reserved.
>   */
>
> @@ -208,4 +209,25 @@ static inline void
> rte_atomic64_clear(rte_atomic64_t *v)
>  }
>  #endif
>
> +static inline int
> +rte_atomic128_cmpset(volatile uint64_t *dst, uint64_t *exp, uint64_t
> *src)
> +{
> +uint8_t res;
> +
> +asm volatile (
> +      MPLOCKED
> +      "cmpxchg16b %[dst];"
> +      " sete %[res]"
> +      : [dst] "=m" (*dst),
> +[res] "=r" (res)
> +      : "c" (src[1]),
> +"b" (src[0]),
> +"m" (*dst),
> +"d" (exp[1]),
> +"a" (exp[0])
> +      : "memory");
> +
> +return res;
> +}
> +

CONFIG_RTE_DRIVER_MEMPOOL_NB_STACK=y can't coexist with RTE_FORCE_INTRINSICS=y, 
this should be explicitly described somewhere in the configuration and 
documentations.

>  #endif /* _RTE_ATOMIC_X86_64_H_ */
> --
> 2.13.6

IMPORTANT NOTICE: The contents of this email and any attachments are 
confidential and may also be privileged. If you are not the intended recipient, 
please notify the sender immediately and do not disclose the contents to any 
other person, use it for any purpose, or store or copy the information in any 
medium. Thank you.