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From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Marvin Liu <yong.liu@intel.com>,
	chenbo.xia@intel.com, zhihong.wang@intel.com
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v2 4/5] vhost: add packed ring vectorized dequeue
Date: Tue, 6 Oct 2020 17:18:51 +0200
Message-ID: <623bd2a5-9ab7-0f64-7099-f64c350cfeba@redhat.com> (raw)
In-Reply-To: <20200921064837.15957-5-yong.liu@intel.com>



On 9/21/20 8:48 AM, Marvin Liu wrote:
> Optimize vhost packed ring dequeue path with SIMD instructions. Four
> descriptors status check and writeback are batched handled with AVX512
> instructions. Address translation operations are also accelerated by
> AVX512 instructions.
> 
> If platform or compiler not support vectorization, will fallback to
> default path.
> 
> Signed-off-by: Marvin Liu <yong.liu@intel.com>
> 
> diff --git a/lib/librte_vhost/meson.build b/lib/librte_vhost/meson.build
> index cc9aa65c67..c1481802d7 100644
> --- a/lib/librte_vhost/meson.build
> +++ b/lib/librte_vhost/meson.build
> @@ -8,6 +8,22 @@ endif
>  if has_libnuma == 1
>  	dpdk_conf.set10('RTE_LIBRTE_VHOST_NUMA', true)
>  endif
> +
> +if arch_subdir == 'x86'
> +        if not machine_args.contains('-mno-avx512f')
> +                if cc.has_argument('-mavx512f') and cc.has_argument('-mavx512vl') and cc.has_argument('-mavx512bw')
> +                        cflags += ['-DCC_AVX512_SUPPORT']
> +                        vhost_avx512_lib = static_library('vhost_avx512_lib',
> +                                              'vhost_vec_avx.c',
> +                                              dependencies: [static_rte_eal, static_rte_mempool,
> +                                                  static_rte_mbuf, static_rte_ethdev, static_rte_net],
> +                                              include_directories: includes,
> +                                              c_args: [cflags, '-mavx512f', '-mavx512bw', '-mavx512vl'])
> +                        objs += vhost_avx512_lib.extract_objects('vhost_vec_avx.c')
> +                endif
> +        endif
> +endif
> +
>  if (toolchain == 'gcc' and cc.version().version_compare('>=8.3.0'))
>  	cflags += '-DVHOST_GCC_UNROLL_PRAGMA'
>  elif (toolchain == 'clang' and cc.version().version_compare('>=3.7.0'))
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 4a81f18f01..fc7daf2145 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -1124,4 +1124,12 @@ virtio_dev_pktmbuf_alloc(struct virtio_net *dev, struct rte_mempool *mp,
>  	return NULL;
>  }
>  
> +int
> +vhost_reserve_avail_batch_packed_avx(struct virtio_net *dev,
> +				 struct vhost_virtqueue *vq,
> +				 struct rte_mempool *mbuf_pool,
> +				 struct rte_mbuf **pkts,
> +				 uint16_t avail_idx,
> +				 uintptr_t *desc_addrs,
> +				 uint16_t *ids);
>  #endif /* _VHOST_NET_CDEV_H_ */
> diff --git a/lib/librte_vhost/vhost_vec_avx.c b/lib/librte_vhost/vhost_vec_avx.c
> new file mode 100644
> index 0000000000..dc5322d002
> --- /dev/null
> +++ b/lib/librte_vhost/vhost_vec_avx.c
> @@ -0,0 +1,181 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2010-2016 Intel Corporation
> + */
> +#include <stdint.h>
> +
> +#include "vhost.h"
> +
> +#define BYTE_SIZE 8
> +/* reference count offset in mbuf rearm data */
> +#define REFCNT_BITS_OFFSET ((offsetof(struct rte_mbuf, refcnt) - \
> +	offsetof(struct rte_mbuf, rearm_data)) * BYTE_SIZE)
> +/* segment number offset in mbuf rearm data */
> +#define SEG_NUM_BITS_OFFSET ((offsetof(struct rte_mbuf, nb_segs) - \
> +	offsetof(struct rte_mbuf, rearm_data)) * BYTE_SIZE)
> +
> +/* default rearm data */
> +#define DEFAULT_REARM_DATA (1ULL << SEG_NUM_BITS_OFFSET | \
> +	1ULL << REFCNT_BITS_OFFSET)
> +
> +#define DESC_FLAGS_SHORT_OFFSET (offsetof(struct vring_packed_desc, flags) / \
> +	sizeof(uint16_t))
> +
> +#define DESC_FLAGS_SHORT_SIZE (sizeof(struct vring_packed_desc) / \
> +	sizeof(uint16_t))
> +#define BATCH_FLAGS_MASK (1 << DESC_FLAGS_SHORT_OFFSET | \
> +	1 << (DESC_FLAGS_SHORT_OFFSET + DESC_FLAGS_SHORT_SIZE) | \
> +	1 << (DESC_FLAGS_SHORT_OFFSET + DESC_FLAGS_SHORT_SIZE * 2)  | \
> +	1 << (DESC_FLAGS_SHORT_OFFSET + DESC_FLAGS_SHORT_SIZE * 3))
> +
> +#define FLAGS_BITS_OFFSET ((offsetof(struct vring_packed_desc, flags) - \
> +	offsetof(struct vring_packed_desc, len)) * BYTE_SIZE)
> +
> +#define PACKED_FLAGS_MASK ((0ULL | VRING_DESC_F_AVAIL | VRING_DESC_F_USED) \
> +	<< FLAGS_BITS_OFFSET)
> +#define PACKED_AVAIL_FLAG ((0ULL | VRING_DESC_F_AVAIL) << FLAGS_BITS_OFFSET)
> +#define PACKED_AVAIL_FLAG_WRAP ((0ULL | VRING_DESC_F_USED) << \
> +	FLAGS_BITS_OFFSET)
> +
> +#define DESC_FLAGS_POS 0xaa
> +#define MBUF_LENS_POS 0x6666
> +
> +int
> +vhost_reserve_avail_batch_packed_avx(struct virtio_net *dev,
> +				 struct vhost_virtqueue *vq,
> +				 struct rte_mempool *mbuf_pool,
> +				 struct rte_mbuf **pkts,
> +				 uint16_t avail_idx,
> +				 uintptr_t *desc_addrs,
> +				 uint16_t *ids)
> +{
> +	struct vring_packed_desc *descs = vq->desc_packed;
> +	uint32_t descs_status;
> +	void *desc_addr;
> +	uint16_t i;
> +	uint8_t cmp_low, cmp_high, cmp_result;
> +	uint64_t lens[PACKED_BATCH_SIZE];
> +	struct virtio_net_hdr *hdr;
> +
> +	if (unlikely(avail_idx & PACKED_BATCH_MASK))
> +		return -1;
> +
> +	/* load 4 descs */
> +	desc_addr = &vq->desc_packed[avail_idx];
> +	__m512i desc_vec = _mm512_loadu_si512(desc_addr);
> +
> +	/* burst check four status */
> +	__m512i avail_flag_vec;
> +	if (vq->avail_wrap_counter)
> +#if defined(RTE_ARCH_I686)
> +		avail_flag_vec = _mm512_set4_epi64(PACKED_AVAIL_FLAG, 0x0,
> +					PACKED_FLAGS_MASK, 0x0);
> +#else
> +		avail_flag_vec = _mm512_maskz_set1_epi64(DESC_FLAGS_POS,
> +					PACKED_AVAIL_FLAG);
> +
> +#endif
> +	else
> +#if defined(RTE_ARCH_I686)
> +		avail_flag_vec = _mm512_set4_epi64(PACKED_AVAIL_FLAG_WRAP,
> +					0x0, PACKED_AVAIL_FLAG_WRAP, 0x0);
> +#else
> +		avail_flag_vec = _mm512_maskz_set1_epi64(DESC_FLAGS_POS,
> +					PACKED_AVAIL_FLAG_WRAP);
> +#endif
> +
> +	descs_status = _mm512_cmp_epu16_mask(desc_vec, avail_flag_vec,
> +		_MM_CMPINT_NE);
> +	if (descs_status & BATCH_FLAGS_MASK)
> +		return -1;
> +


Also, please try to factorize code to avoid duplication between Tx and
Rx paths for desc address translation:
> +	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) {
> +		vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
> +			uint64_t size = (uint64_t)descs[avail_idx + i].len;
> +			desc_addrs[i] = __vhost_iova_to_vva(dev, vq,
> +				descs[avail_idx + i].addr, &size,
> +				VHOST_ACCESS_RO);
> +
> +			if (!desc_addrs[i])
> +				goto free_buf;
> +			lens[i] = descs[avail_idx + i].len;
> +			rte_prefetch0((void *)(uintptr_t)desc_addrs[i]);
> +
> +			pkts[i] = virtio_dev_pktmbuf_alloc(dev, mbuf_pool,
> +					lens[i]);
> +			if (!pkts[i])
> +				goto free_buf;
> +		}
> +	} else {> +		/* check buffer fit into one region & translate address */
> +		__m512i regions_low_addrs =
> +			_mm512_loadu_si512((void *)&dev->regions_low_addrs);
> +		__m512i regions_high_addrs =
> +			_mm512_loadu_si512((void *)&dev->regions_high_addrs);
> +		vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
> +			uint64_t addr_low = descs[avail_idx + i].addr;
> +			uint64_t addr_high = addr_low +
> +						descs[avail_idx + i].len;
> +			__m512i low_addr_vec = _mm512_set1_epi64(addr_low);
> +			__m512i high_addr_vec = _mm512_set1_epi64(addr_high);
> +
> +			cmp_low = _mm512_cmp_epi64_mask(low_addr_vec,
> +					regions_low_addrs, _MM_CMPINT_NLT);
> +			cmp_high = _mm512_cmp_epi64_mask(high_addr_vec,
> +					regions_high_addrs, _MM_CMPINT_LT);
> +			cmp_result = cmp_low & cmp_high;
> +			int index = __builtin_ctz(cmp_result);
> +			if (unlikely((uint32_t)index >= dev->mem->nregions))
> +				goto free_buf;
> +
> +			desc_addrs[i] = addr_low +
> +				dev->mem->regions[index].host_user_addr -
> +				dev->mem->regions[index].guest_phys_addr;
> +			lens[i] = descs[avail_idx + i].len;
> +			rte_prefetch0((void *)(uintptr_t)desc_addrs[i]);
> +
> +			pkts[i] = virtio_dev_pktmbuf_alloc(dev, mbuf_pool,
> +					lens[i]);
> +			if (!pkts[i])
> +				goto free_buf;
> +		}
> +	}
> +
> +	if (virtio_net_with_host_offload(dev)) {
> +		vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
> +			hdr = (struct virtio_net_hdr *)(desc_addrs[i]);
> +			vhost_dequeue_offload(hdr, pkts[i]);
> +		}
> +	}
> +
> +	if (unlikely(virtio_net_is_inorder(dev))) {
> +		ids[PACKED_BATCH_SIZE - 1] =
> +			descs[avail_idx + PACKED_BATCH_SIZE - 1].id;
> +	} else {
> +		vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
> +			ids[i] = descs[avail_idx + i].id;
> +	}
> +
> +	uint64_t addrs[PACKED_BATCH_SIZE << 1];
> +	/* store mbuf data_len, pkt_len */
> +	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
> +		addrs[i << 1] = (uint64_t)pkts[i]->rx_descriptor_fields1;
> +		addrs[(i << 1) + 1] = (uint64_t)pkts[i]->rx_descriptor_fields1
> +					+ sizeof(uint64_t);
> +	}
> +
> +	/* save pkt_len and data_len into mbufs */
> +	__m512i value_vec = _mm512_maskz_shuffle_epi32(MBUF_LENS_POS, desc_vec,
> +					0xAA);
> +	__m512i offsets_vec = _mm512_maskz_set1_epi32(MBUF_LENS_POS,
> +					(uint32_t)-12);
> +	value_vec = _mm512_add_epi32(value_vec, offsets_vec);
> +	__m512i vindex = _mm512_loadu_si512((void *)addrs);
> +	_mm512_i64scatter_epi64(0, vindex, value_vec, 1);
> +
> +	return 0;
> +free_buf:
> +	for (i = 0; i < PACKED_BATCH_SIZE; i++)
> +		rte_pktmbuf_free(pkts[i]);
> +
> +	return -1;
> +}
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 6107662685..e4d2e2e7d6 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -2249,6 +2249,28 @@ vhost_reserve_avail_batch_packed(struct virtio_net *dev,
>  	return -1;
>  }
>  
> +static __rte_always_inline int
> +vhost_handle_avail_batch_packed(struct virtio_net *dev,
> +				 struct vhost_virtqueue *vq,
> +				 struct rte_mempool *mbuf_pool,
> +				 struct rte_mbuf **pkts,
> +				 uint16_t avail_idx,
> +				 uintptr_t *desc_addrs,
> +				 uint16_t *ids)
> +{
> +	if (unlikely(dev->vectorized))
> +#ifdef CC_AVX512_SUPPORT
> +		return vhost_reserve_avail_batch_packed_avx(dev, vq, mbuf_pool,
> +				pkts, avail_idx, desc_addrs, ids);
> +#else
> +		return vhost_reserve_avail_batch_packed(dev, vq, mbuf_pool,
> +				pkts, avail_idx, desc_addrs, ids);
> +
> +#endif
> +	return vhost_reserve_avail_batch_packed(dev, vq, mbuf_pool, pkts,
> +			avail_idx, desc_addrs, ids);
> +}
> +
>  static __rte_always_inline int
>  virtio_dev_tx_batch_packed(struct virtio_net *dev,
>  			   struct vhost_virtqueue *vq,
> @@ -2261,8 +2283,9 @@ virtio_dev_tx_batch_packed(struct virtio_net *dev,
>  	uint16_t ids[PACKED_BATCH_SIZE];
>  	uint16_t i;
>  
> -	if (vhost_reserve_avail_batch_packed(dev, vq, mbuf_pool, pkts,
> -					     avail_idx, desc_addrs, ids))
> +
> +	if (vhost_handle_avail_batch_packed(dev, vq, mbuf_pool, pkts,
> +		avail_idx, desc_addrs, ids))
>  		return -1;
>  
>  	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
> 


  parent reply	other threads:[~2020-10-06 15:19 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-19  3:24 [dpdk-dev] [PATCH v1 0/5] vhost add vectorized data path Marvin Liu
2020-08-19  3:24 ` [dpdk-dev] [PATCH v1 1/5] vhost: " Marvin Liu
2020-09-21  6:48   ` [dpdk-dev] [PATCH v2 0/5] vhost " Marvin Liu
2020-09-21  6:48     ` [dpdk-dev] [PATCH v2 1/5] vhost: " Marvin Liu
2020-09-21  6:48     ` [dpdk-dev] [PATCH v2 2/5] vhost: reuse packed ring functions Marvin Liu
2020-09-21  6:48     ` [dpdk-dev] [PATCH v2 3/5] vhost: prepare memory regions addresses Marvin Liu
2020-10-06 15:06       ` Maxime Coquelin
2020-09-21  6:48     ` [dpdk-dev] [PATCH v2 4/5] vhost: add packed ring vectorized dequeue Marvin Liu
2020-10-06 14:59       ` Maxime Coquelin
2020-10-08  7:05         ` Liu, Yong
2020-10-06 15:18       ` Maxime Coquelin [this message]
2020-10-09  7:59         ` Liu, Yong
2020-09-21  6:48     ` [dpdk-dev] [PATCH v2 5/5] vhost: add packed ring vectorized enqueue Marvin Liu
2020-10-06 15:00       ` Maxime Coquelin
2020-10-08  7:09         ` Liu, Yong
2020-10-06 13:34     ` [dpdk-dev] [PATCH v2 0/5] vhost add vectorized data path Maxime Coquelin
2020-10-08  6:20       ` Liu, Yong
2020-10-09  8:14   ` [dpdk-dev] [PATCH v3 " Marvin Liu
2020-10-09  8:14     ` [dpdk-dev] [PATCH v3 1/5] vhost: " Marvin Liu
2020-10-09  8:14     ` [dpdk-dev] [PATCH v3 2/5] vhost: reuse packed ring functions Marvin Liu
2020-10-09  8:14     ` [dpdk-dev] [PATCH v3 3/5] vhost: prepare memory regions addresses Marvin Liu
2020-10-09  8:14     ` [dpdk-dev] [PATCH v3 4/5] vhost: add packed ring vectorized dequeue Marvin Liu
2020-10-09  8:14     ` [dpdk-dev] [PATCH v3 5/5] vhost: add packed ring vectorized enqueue Marvin Liu
2020-10-12  8:21     ` [dpdk-dev] [PATCH v3 0/5] vhost add vectorized data path Maxime Coquelin
2020-10-12  9:10       ` Liu, Yong
2020-10-12  9:57         ` Maxime Coquelin
2020-10-12 13:24           ` Liu, Yong
2020-10-15 15:28       ` Liu, Yong
2020-10-15 15:35         ` Maxime Coquelin
2020-08-19  3:24 ` [dpdk-dev] [PATCH v1 2/5] vhost: reuse packed ring functions Marvin Liu
2020-08-19  3:24 ` [dpdk-dev] [PATCH v1 3/5] vhost: prepare memory regions addresses Marvin Liu
2020-08-19  3:24 ` [dpdk-dev] [PATCH v1 4/5] vhost: add packed ring vectorized dequeue Marvin Liu
2020-09-18 13:44   ` Maxime Coquelin
2020-09-21  6:26     ` Liu, Yong
2020-09-21  7:47       ` Liu, Yong
2020-08-19  3:24 ` [dpdk-dev] [PATCH v1 5/5] vhost: add packed ring vectorized enqueue Marvin Liu

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