changing the qdisc class speed rate

changing the qdisc class speed rate

[Piotr Duszyński]

Hi everyone,

I am trying to change the rate parameter of HTB class by using this  
code from within one of my functions :

   struct htb_class *cl;
   cl=htb_find(number,q);

   cl->rate->rate.rate = NEW_RATE_VALUE;

   TC shows the correct values, but the traffic rate doesn't change a  
bit.
   Does anyone have any idea what am I doing wrong ? Maybe there would  
be a faster way by sending a netlink  message ?

Piotrek

Re: changing the qdisc class speed rate

[Stephen Hemminger]

On Thu, 28 May 2009 07:12:33 +0200
Piotr Duszyński <regis44@gmail.com> wrote:

> Hi everyone,
> 
> I am trying to change the rate parameter of HTB class by using this  
> code from within one of my functions :
> 
>    struct htb_class *cl;
>    cl=htb_find(number,q);
> 
>    cl->rate->rate.rate = NEW_RATE_VALUE;
> 
>    TC shows the correct values, but the traffic rate doesn't change a  
> bit.
>    Does anyone have any idea what am I doing wrong ? Maybe there would  
> be a faster way by sending a netlink  message ?
> 
> Piotrek

HTB uses a rate table, so if you want the rate to change, you will need to change the
table as well.

Re: changing the qdisc class speed rate

[Piotrek D]

This is what I have done, the  cl->rate->rate.rate refers to the __u32
rate in htb_class -> qdisc_rate_table -> tc_ratespec .
What else should I modify to make this work ?

Piotrek


W dniu 28 maja 2009 07:21 użytkownik Stephen Hemminger
<shemminger@vyatta.com> napisał:
> On Thu, 28 May 2009 07:12:33 +0200
> Piotr Duszyński <regis44@gmail.com> wrote:
>
>> Hi everyone,
>>
>> I am trying to change the rate parameter of HTB class by using this
>> code from within one of my functions :
>>
>>    struct htb_class *cl;
>>    cl=htb_find(number,q);
>>
>>    cl->rate->rate.rate = NEW_RATE_VALUE;
>>
>>    TC shows the correct values, but the traffic rate doesn't change a
>> bit.
>>    Does anyone have any idea what am I doing wrong ? Maybe there would
>> be a faster way by sending a netlink  message ?
>>
>> Piotrek
>
> HTB uses a rate table, so if you want the rate to change, you will need to change the
> table as well.
>

Re: changing the qdisc class speed rate

[Jarek Poplawski]

Piotrek D wrote, On 05/29/2009 09:03 PM:

> This is what I have done, the  cl->rate->rate.rate refers to the __u32
> rate in htb_class -> qdisc_rate_table -> tc_ratespec .
> What else should I modify to make this work ?
> 

From include/net/sch_generic.h:

/* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
   long it will take to send a packet given its size.
 */
static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
{
        int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
        if (slot < 0)
                slot = 0;
        slot >>= rtab->rate.cell_log;
        if (slot > 255)
                return (rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF]);
        return rtab->data[slot];
}

This function controls rates and these rtab values matter here.

Jarek P.


> 
> 
> W dniu 28 maja 2009 07:21 użytkownik Stephen Hemminger
> <shemminger@vyatta.com> napisał:
>> On Thu, 28 May 2009 07:12:33 +0200
>> Piotr Duszyński <regis44@gmail.com> wrote:
>>
>>> Hi everyone,
>>>
>>> I am trying to change the rate parameter of HTB class by using this
>>> code from within one of my functions :
>>>
>>>    struct htb_class *cl;
>>>    cl=htb_find(number,q);
>>>
>>>    cl->rate->rate.rate = NEW_RATE_VALUE;
>>>
>>>    TC shows the correct values, but the traffic rate doesn't change a
>>> bit.
>>>    Does anyone have any idea what am I doing wrong ? Maybe there would
>>> be a faster way by sending a netlink  message ?
>>>
>>> Piotrek
>> HTB uses a rate table, so if you want the rate to change, you will need to change the
>> table as well.
>>
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Re: changing the qdisc class speed rate

[Piotrek D]

Thanks, this was exactly what I was looking for :)
After multiplying  all of the values in the rtab->data array I have
been able to change the traffic rate for that queue.

Piotrek D.


> /* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
>   long it will take to send a packet given its size.
>  */
> static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
> {
>        int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
>        if (slot < 0)
>                slot = 0;
>        slot >>= rtab->rate.cell_log;
>        if (slot > 255)
>                return (rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF]);
>        return rtab->data[slot];
> }
>
> This function controls rates and these rtab values matter here.
>
> Jarek P.
>

>> --