From patchwork Tue Oct 27 18:16:39 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [5/5] tap: drain queue in tap_send() Date: Tue, 27 Oct 2009 08:16:39 -0000 From: Mark McLoughlin X-Patchwork-Id: 37021 Message-Id: <1256667399-3149-6-git-send-email-markmc@redhat.com> To: qemu-devel@nongnu.org Cc: Sven Rudolph , Scott Tsai , Mark McLoughlin Okay, let's try re-enabling the drain-entire-queue behaviour, with a difference - before each subsequent packet, use qemu_can_send_packet() to check that we can send it. This is similar to how we check before polling the tap fd and avoids having to drop a packet if the receiver cannot handle it. This patch should be a performance improvement since we no longer have to go through the mainloop for each packet. Signed-off-by: Mark McLoughlin --- net/tap.c | 33 ++++++++++++++++++--------------- 1 files changed, 18 insertions(+), 15 deletions(-) diff --git a/net/tap.c b/net/tap.c index f32226b..5272d7d 100644 --- a/net/tap.c +++ b/net/tap.c @@ -187,23 +187,26 @@ static void tap_send_completed(VLANClientState *vc, ssize_t len) static void tap_send(void *opaque) { TAPState *s = opaque; - uint8_t *buf = s->buf; int size; - size = tap_read_packet(s->fd, s->buf, sizeof(s->buf)); - if (size <= 0) { - return; - } + do { + uint8_t *buf = s->buf; - if (s->has_vnet_hdr && !s->using_vnet_hdr) { - buf += sizeof(struct virtio_net_hdr); - size -= sizeof(struct virtio_net_hdr); - } + size = tap_read_packet(s->fd, s->buf, sizeof(s->buf)); + if (size <= 0) { + break; + } - size = qemu_send_packet_async(s->vc, buf, size, tap_send_completed); - if (size == 0) { - tap_read_poll(s, 0); - } + if (s->has_vnet_hdr && !s->using_vnet_hdr) { + buf += sizeof(struct virtio_net_hdr); + size -= sizeof(struct virtio_net_hdr); + } + + size = qemu_send_packet_async(s->vc, buf, size, tap_send_completed); + if (size == 0) { + tap_read_poll(s, 0); + } + } while (size > 0 && qemu_can_send_packet(s->vc)); } int tap_has_ufo(VLANClientState *vc)