Re: [RFC v3 3/7] vsock: batch buffers in tx
flat view
From: Eugenio Perez Martin <eperezma@redhat.com>
Date: 2022-09-01 09:02:11
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On Thu, Sep 1, 2022 at 7:55 AM Guo Zhi [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Vsock uses buffers in order, and for tx driver doesn't have to know the length of the buffer. So we can do a batch for vsock if in order negotiated, only write one used ring for a batch of buffers Signed-off-by: Guo Zhi <redacted> --- drivers/vhost/vsock.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 368330417bde..e08fbbb5439e 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c@@ -497,7 +497,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work) struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock, dev); struct virtio_vsock_pkt *pkt; - int head, pkts = 0, total_len = 0; + int head, pkts = 0, total_len = 0, add = 0; unsigned int out, in; bool added = false;@@ -551,10 +551,18 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work) else virtio_transport_free_pkt(pkt); - vhost_add_used(vq, head, 0); + if (!vhost_has_feature(vq, VIRTIO_F_IN_ORDER)) { + vhost_add_used(vq, head, 0); + } else { + vq->heads[add].id = head; + vq->heads[add++].len = 0;
Knowing that the descriptors are used in order we can save a few memory writes to the vq->heads[] array. vhost.c is checking for the feature in_order anyway. Thanks!
+ }
added = true;
} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
+ /* If in order feature negotiaged, we can do a batch to increase performance */
+ if (vhost_has_feature(vq, VIRTIO_F_IN_ORDER) && added)
+ vhost_add_used_n(vq, vq->heads, add);
no_more_replies:
if (added)
vhost_signal(&vsock->dev, vq);
--
2.17.1