From: Yang Yingliang <yangyingliang@huawei•com>
To: Hiroaki SHIMODA <shimoda.hiroaki@gmail•com>
Cc: <netdev@vger•kernel.org>
Subject: Re: [PATCH net-next 0/5] net_sched: Adjust qdisc_change() for command "#tc qdisc change/replace ..."
Date: Fri, 7 Mar 2014 10:29:44 +0800 [thread overview]
Message-ID: <53192F18.9020900@huawei.com> (raw)
In-Reply-To: <20140307060818.fa549a2981b601bcec517227@gmail.com>
On 2014/3/7 5:08, Hiroaki SHIMODA wrote:
> On Thu, 6 Mar 2014 21:08:36 +0800
> Yang Yingliang <yangyingliang@huawei•com> wrote:
>
>> Current commands "#tc qdisc replace..." and "#tc qdisc change..."
>> are not doing what they're supposed to do.
>>
>> E.g.
>>
>> With "#tc qdisc replace ...", it won't clear old option if not specified in
>> qdisc of netem.
>>
>> # tc qdisc add dev eth4 handle 1: root netem rate 10mbit
>> # tc qdisc show
>> qdisc netem 1: dev eth4 root refcnt 2 limit 1000 rate 10Mbit
>>
>> # tc qdisc replace dev eth4 handle 1: root netem latency 10ms
>> # tc qdisc show
>> qdisc netem 1: dev eth4 root refcnt 2 limit 1000 delay 10.0ms rate 10Mbit
>> The old option "rate" is still there.
>
> It looks like you are trying to replace existing qdisc 1: with
> the same qdisc 1:. So the effect is the same as change.
> If you want to do replace the existing qdisc, you should specify
> other handle or different qdisc.
>
>> With "#tc qdisc change ... ", it will clear old options if not specified in
>> qdisc of tbf.
>>
>> # tc qdisc add dev eth4 handle 1: root tbf rate 10mbit burst 10kb latency 50ms mtu 64kb peakrate 20mbit
>> # tc qdisc show
>> qdisc tbf 1: dev eth4 root refcnt 2 rate 10Mbit burst 10Kb peakrate 20Mbit minburst 64Kb lat 50.0ms
>> # tc qdisc change dev eth4 handle 1: root tbf rate 20mbit burst 10kb latency 50ms
>> # tc qdisc show
>> qdisc tbf 1: dev eth4 root refcnt 2 rate 20Mbit burst 10Kb lat 50.0ms
>> The old peakrate and minburst are cleared.
>
> You are assumed to implicitly specify "peakrate 0" at change.
> It seems that you are arguing the tc command, not kernel code.
> There would exist userland commmand whose rate and peakrate
> command options are always mandatory.
> How they support its command options is up to userland I think.
>
peakrate is not specified, it should not be changed, I think.
peakrate is not mandatory.
I think tc command has no big problem and the real problem is kernel
code treats "change" as "replace", sometimes it treats "replace" as
"change".
Thanks!
prev parent reply other threads:[~2014-03-07 2:29 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-06 13:08 [PATCH net-next 0/5] net_sched: Adjust qdisc_change() for command "#tc qdisc change/replace ..." Yang Yingliang
2014-03-06 13:08 ` [PATCH net-next 1/5] net_sched: add flag parameter in qdisc_change Yang Yingliang
2014-03-06 13:08 ` [PATCH net-next 2/5] net_sched: add replace func in struct Qdisc_ops Yang Yingliang
2014-03-06 14:55 ` Eric Dumazet
2014-03-07 2:13 ` Yang Yingliang
2014-03-06 13:08 ` [PATCH net-next 3/5] sch_tbf: change name "tbf_change" to "tbf_replace" Yang Yingliang
2014-03-06 13:08 ` [PATCH net-next 4/5] sch_tbf: add tbf_change for #tc qdisc change Yang Yingliang
2014-03-06 13:08 ` [PATCH net-next 5/5] sch_netem: add netem_replace for #tc qdisc replace Yang Yingliang
2014-03-06 13:16 ` [PATCH net-next 0/5] net_sched: Adjust qdisc_change() for command "#tc qdisc change/replace ..." Hagen Paul Pfeifer
2014-03-07 2:16 ` Yang Yingliang
2014-03-06 21:08 ` Hiroaki SHIMODA
2014-03-07 2:29 ` Yang Yingliang [this message]
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