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

[Maxime Coquelin]

On 4/25/22 14:10, Xia, Chenbo wrote:

Hi Maxime,

-----Original Message-----
From: Maxime Coquelin <maxime.coque...@redhat.com>
Sent: Thursday, March 24, 2022 8:47 PM
To: dev@dpdk.org; Xia, Chenbo <chenbo....@intel.com>;
david.march...@redhat.com; i.maxim...@ovn.org
Cc: Maxime Coquelin <maxime.coque...@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.coque...@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.

Good catch, I'll remove it in next revision.

Regards,
Maxime

Thanks,
Chenbo

  };

  /**
--
2.35.1