RE: [PATCH v2 5/5] vhost: add statistics for IOTLB

["Xia, Chenbo" <chenbo.xia@intel.com>]

Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Thursday, March 24, 2022 8:47 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>;
> david.marchand@redhat.com; i.maximets@ovn.org
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v2 5/5] vhost: add statistics for IOTLB
> 
> This patch adds statistics for IOTLB hits and misses.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/vhost/vhost.c | 10 +++++++++-
>  lib/vhost/vhost.h |  3 +++
>  2 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
> index 58b58fc40e..7f4fafdcb0 100644
> --- a/lib/vhost/vhost.c
> +++ b/lib/vhost/vhost.c
> @@ -43,6 +43,8 @@ static const struct vhost_vq_stats_name_off
> vhost_vq_stat_strings[] = {
>  	{"size_1024_1518_packets", offsetof(struct vhost_virtqueue,
> stats.size_bins[6])},
>  	{"size_1519_max_packets",  offsetof(struct vhost_virtqueue,
> stats.size_bins[7])},
>  	{"guest_notifications",    offsetof(struct vhost_virtqueue,
> stats.guest_notifications)},
> +	{"iotlb_hits",             offsetof(struct vhost_virtqueue,
> stats.iotlb_hits)},
> +	{"iotlb_misses",           offsetof(struct vhost_virtqueue,
> stats.iotlb_misses)},
>  };
> 
>  #define VHOST_NB_VQ_STATS RTE_DIM(vhost_vq_stat_strings)
> @@ -60,8 +62,14 @@ __vhost_iova_to_vva(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	tmp_size = *size;
> 
>  	vva = vhost_user_iotlb_cache_find(vq, iova, &tmp_size, perm);
> -	if (tmp_size == *size)
> +	if (tmp_size == *size) {
> +		if (dev->flags & VIRTIO_DEV_STATS_ENABLED)
> +			vq->stats.iotlb_hits++;
>  		return vva;
> +	}
> +
> +	if (dev->flags & VIRTIO_DEV_STATS_ENABLED)
> +		vq->stats.iotlb_misses++;
> 
>  	iova += tmp_size;
> 
> diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
> index 13c5c2266d..e876fc157b 100644
> --- a/lib/vhost/vhost.h
> +++ b/lib/vhost/vhost.h
> @@ -134,6 +134,9 @@ struct virtqueue_stats {
>  	/* Size bins in array as RFC 2819, undersized [0], 64 [1], etc */
>  	uint64_t size_bins[8];
>  	uint64_t guest_notifications;
> +	uint64_t iotlb_hits;
> +	uint64_t iotlb_misses;
> +	uint64_t iotlb_errors;

This seems defined but never used.

Thanks,
Chenbo

>  };
> 
>  /**
> --
> 2.35.1