<div dir="ltr">The reason I am confused is that when I use this combination of commands:<div><br><div><span style="font-family:arial,sans-serif;font-size:13.63636302947998px">tc qdisc add dev $IFACE root handle 1: htb default 1</span><br style="font-family:arial,sans-serif;font-size:13.63636302947998px">
<span style="font-family:arial,sans-serif;font-size:13.63636302947998px">tc class add dev $IFACE parent 1: classid 1:1 htb rate 40mbit</span><br></div><div>tc qdisc del dev eth4 parent 1:1 handle 10: sfq perturb 10<br></div>
</div><div><br></div><div>And sending packet from the sender, where qdisc is set, to the receiver, the queuing delay is quite small and is approximately the same as when fq_codel enabled.</div><div><br></div><div>However, if I am not using sfq, and send only one flow over this link, the delay will explode again.</div>
<div><br></div><div>So is sfq here cut off the queue length somehow? How should I make a bufferbloat fair queue on linux box using tc qdisc?</div><div><br></div><div>Thanks</div><div>-Mo</div></div><div class="gmail_extra">
<br><br><div class="gmail_quote">2013/12/5 Dong Mo <span dir="ltr"><<a href="mailto:montedong@gmail.com" target="_blank">montedong@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Thanks for the reply and I think I have successfully set up codel. Unfortunately I am also new to qdisc.<div><br></div><div>I am trying to compare fq_codel and sfq's performance. I was wondering how to setup a software rate limiting using htb and at the same time have sfq on this bottleneck link using qdisc.</div>
<div><br></div><div>Thank you so much!</div><span class="HOEnZb"><font color="#888888"><div>-Mo</div></font></span></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><br><div class="gmail_quote">2013/11/23 Dave Taht <span dir="ltr"><<a href="mailto:dave.taht@gmail.com" target="_blank">dave.taht@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><p dir="ltr">Why burst 15k? Quantum 1514 works for me.</p>
<p dir="ltr">While htb will give the best results it is also the most CPU intensive.</p>
<p dir="ltr">I also note that running it on ingress can be useful especially with ecn.</p>
<p dir="ltr">IF you have a simple network driver with no ring buffer... Or you have working BQL... And you want to run at line rate at 100 Mbit... You can tell your Ethernet driver to switch to 100mbit via</p>
<p dir="ltr">ethtool -s your device advertise 0x008 </p>
<p dir="ltr">See also caveats on tso etc:</p>
<p dir="ltr"><a href="http://www.bufferbloat.net/projects/codel/wiki/Best_Practices_for_Benchmarking_CoDel_and_FQ_CoDel" target="_blank">http://www.bufferbloat.net/projects/codel/wiki/Best_Practices_for_Benchmarking_CoDel_and_FQ_CoDel</a><br>
</p>
<div class="gmail_quote"><div><div>On Nov 23, 2013 2:26 AM, "Jonathan Morton" <<a href="mailto:chromatix99@gmail.com" target="_blank">chromatix99@gmail.com</a>> wrote:<br type="attribution"></div>
</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div>
<br>
On 23 Nov, 2013, at 7:04 am, Dong Mo wrote:<br>
<br>
> I am new to codel and I would like to run some experiments with codel on a linux box acting as a router. I see on the wiki that running codel on linux requires BQL support from NIC driver. I would like to know is this an essential requirement to run codel on linux box or it is optional?<br>
<br>
It's not a hard requirement - but large hardware queues (which BQL tries to solve) tend to interfere with line-rate operation.<br>
<br>
> I don't require line rate performance, something like 100Mbps throughput will be enough for the experiment. However, It is also not clear to me that how Codel is going to interact with some software traffic shaping say bandwidth limiting?<br>
<br>
tc qdisc add dev $IFACE root handle 1: htb default 1<br>
tc class add dev $IFACE parent 1: classid 1:1 htb rate $RATE burst 15k<br>
tc qdisc add dev $IFACE parent 1:1 handle 10: fq_codel<br>
<br>
That works perfectly well if $RATE is less than line rate, even without BQL.<br>
<br>
- Jonathan Morton<br>
<br></div></div>
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