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

[Maxime Coquelin <maxime.coquelin@redhat.com>]

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

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

Regards,
Maxime

> Thanks,
> Chenbo
> 
>>   };
>>
>>   /**
>> --
>> 2.35.1
>