From: Yang Yingliang <yangyingliang@huawei.com>
To: Eric Dumazet <edumazet@google.com>
Cc: <netdev@vger.kernel.org>, "David S. Miller" <davem@davemloft.net>
Subject: net_sched: precision problem of TBF/HTB
Date: Tue, 16 Jul 2013 12:12:05 +0800 [thread overview]
Message-ID: <51E4C815.9000408@huawei.com> (raw)
Hi, Eric
Commit 1def9238d4aa2 (net_sched: more precise pkt_len computation) makes more precise transfer bytes by taking account of headers in qdisc_skb_cb(skb)->pkt_len, but this introduces a problem with calculating bandwidth in userland.
When calculating bandwidth in userland, it's not include headers' bytes. From the user's perspective, it's not a correct bandwidth.
Shall we need take account of headers in qdisc_skb_cb(skb)->pkt_len or just skb->len?
Example:
tc qdisc add dev $DEV root handle 1: tbf latency 50ms burst 500kB rate 500mbit mtu 64k
iperf -c host -t 30 -i 10
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 571 MBytes 479 Mbits/sec
[ 3] 10.0-20.0 sec 570 MBytes 478 Mbits/sec
[ 3] 20.0-30.0 sec 570 MBytes 478 Mbits/sec
[ 3] 0.0-30.0 sec 1.67 GBytes 478 Mbits/sec
next reply other threads:[~2013-07-16 4:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-16 4:12 Yang Yingliang [this message]
2013-07-16 4:50 ` net_sched: precision problem of TBF/HTB Eric Dumazet
2013-07-17 1:41 ` Ding Tianhong
2013-07-17 3:18 ` John Fastabend
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