[dpdk-dev] [PATCH v4 02/14] vhost: unify unroll pragma parameter

Maxime Coquelin maxime.coquelin at redhat.com
Fri Oct 11 14:48:59 CEST 2019



On 10/9/19 3:38 PM, Marvin Liu wrote:
> Add macro for unifying Clang/ICC/GCC unroll pragma format. Batch
> functions were contained of several small loops which optimized by
> compiler’s loop unrolling pragma.
> 
> Signed-off-by: Marvin Liu <yong.liu at intel.com>
> 
> diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
> index 8623e91c0..30839a001 100644
> --- a/lib/librte_vhost/Makefile
> +++ b/lib/librte_vhost/Makefile
> @@ -16,6 +16,24 @@ CFLAGS += -I vhost_user
>  CFLAGS += -fno-strict-aliasing
>  LDLIBS += -lpthread
>  
> +ifeq ($(RTE_TOOLCHAIN), gcc)
> +ifeq ($(shell test $(GCC_VERSION) -ge 83 && echo 1), 1)
> +CFLAGS += -DSUPPORT_GCC_UNROLL_PRAGMA
> +endif
> +endif
> +
> +ifeq ($(RTE_TOOLCHAIN), clang)
> +ifeq ($(shell test $(CLANG_MAJOR_VERSION)$(CLANG_MINOR_VERSION) -ge 37 && echo 1), 1)
> +CFLAGS += -DSUPPORT_CLANG_UNROLL_PRAGMA
> +endif
> +endif
> +
> +ifeq ($(RTE_TOOLCHAIN), icc)
> +ifeq ($(shell test $(ICC_MAJOR_VERSION) -ge 16 && echo 1), 1)
> +CFLAGS += -DSUPPORT_ICC_UNROLL_PRAGMA
> +endif
> +endif
> +
>  ifeq ($(CONFIG_RTE_LIBRTE_VHOST_NUMA),y)
>  LDLIBS += -lnuma
>  endif
> diff --git a/lib/librte_vhost/meson.build b/lib/librte_vhost/meson.build
> index cb1123ae3..ddf0ee579 100644
> --- a/lib/librte_vhost/meson.build
> +++ b/lib/librte_vhost/meson.build
> @@ -8,6 +8,13 @@ endif
>  if has_libnuma == 1
>  	dpdk_conf.set10('RTE_LIBRTE_VHOST_NUMA', true)
>  endif
> +if (toolchain == 'gcc' and cc.version().version_compare('>=8.3.0'))
> +	cflags += '-DSUPPORT_GCC_UNROLL_PRAGMA'
> +elif (toolchain == 'clang' and cc.version().version_compare('>=3.7.0'))
> +	cflags += '-DSUPPORT_CLANG_UNROLL_PRAGMA'
> +elif (toolchain == 'icc' and cc.version().version_compare('>=16.0.0'))
> +	cflags += '-DSUPPORT_ICC_UNROLL_PRAGMA'
> +endif
>  dpdk_conf.set('RTE_LIBRTE_VHOST_POSTCOPY',
>  	      cc.has_header('linux/userfaultfd.h'))
>  version = 4
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 884befa85..4cba8c5ef 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -39,6 +39,24 @@
>  
>  #define VHOST_LOG_CACHE_NR 32
>  
> +#ifdef SUPPORT_GCC_UNROLL_PRAGMA
> +#define UNROLL_PRAGMA_PARAM "GCC unroll 4"

Shouldn't al these defines be either prefixed with VHOST_, or being
declared in EAL headers, so that it can be used by other DPDK libs?

I will pick it as is for now, but please consider above comment and
and send a patch on top if it makes sense.

Thanks,
Maxime
> +#endif
> +
> +#ifdef SUPPORT_CLANG_UNROLL_PRAGMA
> +#define UNROLL_PRAGMA_PARAM "unroll 4"
> +#endif
> +
> +#ifdef SUPPORT_ICC_UNROLL_PRAGMA
> +#define UNROLL_PRAGMA_PARAM "unroll (4)"
> +#endif
> +
> +#ifdef UNROLL_PRAGMA_PARAM
> +#define UNROLL_PRAGMA(param) _Pragma(param)
> +#else
> +#define UNROLL_PRAGMA(param) do {} while (0);
> +#endif
> +
>  /**
>   * Structure contains buffer address, length and descriptor index
>   * from vring to do scatter RX.
> 


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