* [PATCH] bonding: set correct tx_queue_len for bond_dev
@ 2013-07-30 7:20 Yang Yingliang
2013-07-30 7:34 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Yang Yingliang @ 2013-07-30 7:20 UTC (permalink / raw)
To: Jay Vosburgh, Andy Gospodarek, David S. Miller, netdev
When we set bandwidth on bond_dev with htb, it's not precise.
Because the length of skb_buff queue is bigger than sch->limit
whose value is 0, some packets are dropped.
This leads to bond device can't make full use of the bandwidth
and influence the accuracy.
With htb, sch->limit is set from bond_dev->tx_queue_len which
is initialized to 0 in bond_setup.
To fix this issue, set the bond_dev's tx_queue_len to slave_dev's.
Example:
tc qdisc add dev bond0 root handle 1: htb default 1
tc class add dev bond0 parent 1:0 classid 1:1 htb rate 1Gbit ceil 1Gbit
iperf -c host -t 30 -i 10
With old bonding:
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 579 MBytes 486 Mbits/sec
[ 3] 10.0-20.0 sec 604 MBytes 507 Mbits/sec
[ 3] 20.0-30.0 sec 551 MBytes 462 Mbits/sec
[ 3] 0.0-30.0 sec 1.69 GBytes 485 Mbits/sec
With new bonding:
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 1.11 GBytes 955 Mbits/sec
[ 3] 10.0-20.0 sec 1.11 GBytes 955 Mbits/sec
[ 3] 20.0-30.0 sec 1.11 GBytes 955 Mbits/sec
[ 3] 0.0-30.0 sec 3.33 GBytes 955 Mbits/sec
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
drivers/net/bonding/bond_main.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index dbbea0e..2536426 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1860,6 +1860,12 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
goto err_dest_symlinks;
}
+ if (!bond_dev->tx_queue_len)
+ bond_dev->tx_queue_len = slave_dev->tx_queue_len;
+ else
+ bond_dev->tx_queue_len = min(slave_dev->tx_queue_len,
+ bond_dev->tx_queue_len);
+
pr_info("%s: enslaving %s as a%s interface with a%s link.\n",
bond_dev->name, slave_dev->name,
bond_is_active_slave(new_slave) ? "n active" : " backup",
--
1.7.12
.
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] bonding: set correct tx_queue_len for bond_dev
2013-07-30 7:20 [PATCH] bonding: set correct tx_queue_len for bond_dev Yang Yingliang
@ 2013-07-30 7:34 ` David Miller
2013-07-30 9:24 ` Yang Yingliang
0 siblings, 1 reply; 3+ messages in thread
From: David Miller @ 2013-07-30 7:34 UTC (permalink / raw)
To: yangyingliang; +Cc: fubar, andy, netdev
From: Yang Yingliang <yangyingliang@huawei.com>
Date: Tue, 30 Jul 2013 15:20:42 +0800
> With htb, sch->limit is set from bond_dev->tx_queue_len which
> is initialized to 0 in bond_setup.
This is intentional, software devices should not queue TX
packets.
You can only use the packet scheduler with hardware devices.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] bonding: set correct tx_queue_len for bond_dev
2013-07-30 7:34 ` David Miller
@ 2013-07-30 9:24 ` Yang Yingliang
0 siblings, 0 replies; 3+ messages in thread
From: Yang Yingliang @ 2013-07-30 9:24 UTC (permalink / raw)
To: David Miller; +Cc: fubar, andy, netdev
On 2013/7/30 15:34, David Miller wrote:
> From: Yang Yingliang <yangyingliang@huawei.com>
> Date: Tue, 30 Jul 2013 15:20:42 +0800
>
>> With htb, sch->limit is set from bond_dev->tx_queue_len which
>> is initialized to 0 in bond_setup.
>
> This is intentional, software devices should not queue TX
> packets.
This makes software devices with htb qdisc can hold only
one packet, others are dropped.
Maybe sch->limit's default value which is 1 is too small.
Instead of this patch, I'll send another patch to fix this
value for fixing this issue.
>
> You can only use the packet scheduler with hardware devices.
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-07-30 9:25 UTC | newest]
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2013-07-30 7:34 ` David Miller
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