On Thu, 2019-04-11 at 17:04 +0800, Jason Wang wrote: > Btw, forget to mention, I modify your patch to use > netif_stop/wake_subqueue() instead.
Hm...
--- /usr/src/debug/kernel-5.0.fc29/linux-5.0.5-
200.fc29.x86_64/drivers/net/tun.c2019-03-03 23:21:29.000000000 +0000
+++ /home/fedora/tun/tun.c 2019-04-11 09:11:20.781683956 +0000
@@ -1118,8 +1118,14 @@ static netdev_tx_t tun_net_xmit(struct s
nf_reset(skb);
- if (ptr_ring_produce(&tfile->tx_ring, skb))
+ if (ptr_ring_produce(&tfile->tx_ring, skb)) {
+ netif_stop_subqueue(tun->dev, txq);
goto drop;
+ }
+
+ if (ptr_ring_full(&tfile->tx_ring)) {
+ netif_stop_subqueue(tun->dev, txq);
+ }
/* Notify and wake up reader process */
if (tfile->flags & TUN_FASYNC)
@@ -2229,6 +2235,8 @@ static ssize_t tun_do_read(struct tun_st
consume_skb(skb);
}
+ netif_wake_subqueue(tun->dev, tfile->queue_index);
+
return ret;
}
That gives me
Socket Message Elapsed Messages
Size Size Time Okay Errors Throughput
bytes bytes secs # # 10^6bits/sec
212992 1400 10.90 2277474 0 2340.95
212992 10.90 1174728 1207.47
Without the first netif_stop_subqueue() call in the case where we
actually *do* drop the packet (which AFAICT should never happen?) it
looks like this:
Socket Message Elapsed Messages
Size Size Time Okay Errors Throughput
bytes bytes secs # # 10^6bits/sec
212992 1400 10.00 7675563 0 8596.61
212992 10.00 1441186 1614.13
And without the patch at all, it was still faster when I just let it
drop packets:
Socket Message Elapsed Messages
Size Size Time Okay Errors Throughput
bytes bytes secs # # 10^6bits/sec
212992 1400 10.00 8143709 0 9120.93
212992 10.00 1545035 1730.44
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