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From: Adrian Moreno <amorenoz@redhat.com>
To: Joyce Kong <joyce.kong@arm.com>,
	maxime.coquelin@redhat.com, jerinj@marvell.com,
	zhihong.wang@intel.com, xiaolong.ye@intel.com,
	honnappa.nagarahalli@arm.com, phil.yang@arm.com,
	ruifeng.wang@arm.com
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v1 2/2] lib/vhost: restrict pointer aliasing for packed path
Date: Tue, 7 Jul 2020 18:25:52 +0200	[thread overview]
Message-ID: <73e2936e-18b7-43cf-d733-8ca37600b0b8@redhat.com> (raw)
In-Reply-To: <20200611033248.39049-3-joyce.kong@arm.com>


On 6/11/20 5:32 AM, Joyce Kong wrote:
> Restrict pointer aliasing to allow the compiler to vectorize
> loops more aggressively.
> 
> With this patch, a 9.6% improvement is observed in throughput for the
> packed virtio-net PVP case, and a 2.8% improvement in throughput for
> the packed virtio-user PVP case. All performance data are measured
> under 0.001% acceptable packet loss with 1 core on both vhost and
> virtio side.

Is the performance gain related solely to this patch or is it the result of the
combined series?

> 
> Signed-off-by: Joyce Kong <joyce.kong@arm.com>
> Reviewed-by: Phil Yang <phil.yang@arm.com>
> ---
>  lib/librte_vhost/virtio_net.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 751c1f373..39c92e7e1 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -1133,8 +1133,8 @@ virtio_dev_rx_single_packed(struct virtio_net *dev,
>  
>  static __rte_noinline uint32_t
>  virtio_dev_rx_packed(struct virtio_net *dev,
> -		     struct vhost_virtqueue *vq,
> -		     struct rte_mbuf **pkts,
> +		     struct vhost_virtqueue *__restrict vq,
> +		     struct rte_mbuf **__restrict pkts,
>  		     uint32_t count)
>  {
>  	uint32_t pkt_idx = 0;

I wonder if we're extracting the full potential of "restrict" considering that
the heavy lifting is done by the inner functions:
(virtio_dev_rx_batch_packed and virtio_dev_rx_single_packed)

> @@ -1219,7 +1219,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
>  
>  uint16_t
>  rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
> -	struct rte_mbuf **pkts, uint16_t count)
> +	struct rte_mbuf **__restrict pkts, uint16_t count)
>  {
>  	struct virtio_net *dev = get_device(vid);
>  
Is this considered an api change?

> @@ -2124,9 +2124,9 @@ free_zmbuf(struct vhost_virtqueue *vq)
>  
>  static __rte_noinline uint16_t
>  virtio_dev_tx_packed_zmbuf(struct virtio_net *dev,
> -			   struct vhost_virtqueue *vq,
> +			   struct vhost_virtqueue *__restrict vq,
>  			   struct rte_mempool *mbuf_pool,
> -			   struct rte_mbuf **pkts,
> +			   struct rte_mbuf **__restrict pkts,
>  			   uint32_t count)
>  {
>  	uint32_t pkt_idx = 0;
> @@ -2160,9 +2160,9 @@ virtio_dev_tx_packed_zmbuf(struct virtio_net *dev,
>  
>  static __rte_noinline uint16_t
>  virtio_dev_tx_packed(struct virtio_net *dev,
> -		     struct vhost_virtqueue *vq,
> +		     struct vhost_virtqueue *__restrict vq,
>  		     struct rte_mempool *mbuf_pool,
> -		     struct rte_mbuf **pkts,
> +		     struct rte_mbuf **__restrict pkts,
>  		     uint32_t count)
>  {
>  	uint32_t pkt_idx = 0;
> 

-- 
Adrián Moreno


  reply	other threads:[~2020-07-07 16:26 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-11  3:32 [dpdk-dev] [PATCH v1 0/2] virtio: restrict pointer aliasing for loops vectorization Joyce Kong
2020-06-11  3:32 ` [dpdk-dev] [PATCH v1 1/2] net/virtio: restrict pointer aliasing for NEON vpmd Joyce Kong
2020-06-23  8:47   ` Maxime Coquelin
2020-06-23  9:05     ` Phil Yang
2020-06-24  2:58       ` Joyce Kong
2020-06-24  4:16         ` Stephen Hemminger
2020-06-11  3:32 ` [dpdk-dev] [PATCH v1 2/2] lib/vhost: restrict pointer aliasing for packed path Joyce Kong
2020-07-07 16:25   ` Adrian Moreno [this message]
2020-07-10  3:15     ` Joyce Kong
2020-07-06  7:49 ` [dpdk-dev] [PATCH v2 0/6] Restrict pointer aliasing with a common wrapper Joyce Kong
2020-07-06  7:49   ` [dpdk-dev] [PATCH v2 1/6] lib/eal: add a common wrapper for restricted pointers Joyce Kong
2020-07-07  2:15     ` Jerin Jacob
2020-07-07  2:24     ` Phil Yang
2020-07-07  2:40     ` Ruifeng Wang
2020-07-07 13:57     ` David Marchand
2020-07-08  2:46       ` Joyce Kong
2020-07-06  7:49   ` [dpdk-dev] [PATCH v2 2/6] net/virtio: restrict pointer aliasing for NEON vpmd Joyce Kong
2020-07-06  7:49   ` [dpdk-dev] [PATCH v2 3/6] lib/vhost: restrict pointer aliasing for packed vpmd Joyce Kong
2020-07-07 13:58     ` David Marchand
2020-07-06  7:49   ` [dpdk-dev] [PATCH v2 4/6] net/i40e: replace restrict with rte restrict Joyce Kong
2020-07-07  2:25     ` Phil Yang
2020-07-07  2:43     ` Ruifeng Wang
2020-07-07 14:00     ` David Marchand
2020-07-08  3:21       ` Joyce Kong
2020-07-09  9:57         ` David Marchand
2020-07-10  2:45           ` Joyce Kong
2020-07-06  7:49   ` [dpdk-dev] [PATCH v2 5/6] examples/performance-thread: replace restrict with wrapper Joyce Kong
2020-07-07  2:27     ` Phil Yang
2020-07-07  2:45     ` Ruifeng Wang
2020-07-06  7:49   ` [dpdk-dev] [PATCH v2 6/6] net/mlx5: replace restrict keyword with rte restrict Joyce Kong
2020-07-07  2:28     ` Phil Yang
2020-07-07  2:47     ` Ruifeng Wang
2020-07-09 13:52   ` [dpdk-dev] [PATCH v2 0/6] Restrict pointer aliasing with a commonwrapper Morten Brørup
2020-07-10  3:17     ` Joyce Kong
2020-07-10  2:38 ` [dpdk-dev] [PATCH v3 0/3] restrict pointer aliasing with a common wrapper Joyce Kong
2020-07-10  2:38   ` [dpdk-dev] [PATCH v3 1/3] lib/eal: add a common wrapper for restricted pointers Joyce Kong
2020-07-10  2:38   ` [dpdk-dev] [PATCH v3 2/3] net/virtio: restrict pointer aliasing for NEON vpmd Joyce Kong
2020-07-10  2:38   ` [dpdk-dev] [PATCH v3 3/3] lib/vhost: restrict pointer aliasing for packed vpmd Joyce Kong
2020-07-10 13:41     ` Adrian Moreno
2020-07-10 14:05   ` [dpdk-dev] [PATCH v3 0/3] restrict pointer aliasing with a common wrapper David Marchand

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