From: Dor Laor <[EMAIL PROTECTED]>
The current start_xmit sets 500us hrtimer to kick the host.
The problem is that if another xmit happens before the timer was fired then
the first xmit will have to wait additional 500us.
This patch does not re-arm the timer if there is existing one.
This will shorten the latency for tx.
It improves tx throughput by 20%
Signed-off-by: Dor Laor <[EMAIL PROTECTED]>
---
drivers/net/virtio_net.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 538cc37..0403d65 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -392,10 +392,10 @@ again:
vi->stats.sendq_kicks++;
vi->svq->vq_ops->kick(vi->svq);
vi->out_num = 0;
- } else {
- vi->stats.hrtimer_starts++;
- hrtimer_start(&vi->tx_timer, ktime_set(0,500000),
- HRTIMER_MODE_REL);
+ } else if (!hrtimer_is_queued(&vi->tx_timer)) {
+ vi->stats.hrtimer_starts++;
+ hrtimer_start(&vi->tx_timer, ktime_set(0,500000),
+ HRTIMER_MODE_REL);
}
return 0;
}
--
1.5.3.3
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