[LARTC] RED problem !

[LARTC] RED problem !

[Arindam Haldar]

hi  all,

while trying red inplace of sfq/pfifo i go the follwing error

tc qdisc add dev eth0 parent 1:470 red max 12288 min 6100 limit 12288 
avpkt 1514 burst 2

RED : failed to calculate EWMA constant

i have the scheduling as modules, so i did insmod & tried again but the 
result was same !

pls can anyone tell me whats the mistake

thanx in anticipation
arindam haldar


_______________________________________________
LARTC mailing list / LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://ds9a.nl/lartc/

Re: [LARTC] RED problem !

[bert hubert]

On Tue, Jan 01, 2002 at 10:33:06PM +0530, Arindam Haldar wrote:
> hi  all,
> 
> while trying red inplace of sfq/pfifo i go the follwing error
> 
> tc qdisc add dev eth0 parent 1:470 red max 12288 min 6100 limit 12288 
> avpkt 1514 burst 2

This returns -1:

int tc_red_eval_ewma(unsigned qmin, unsigned burst, unsigned avpkt)
{
        int wlog = 1;
        double W = 0.5;
        double a = (double)burst + 1 - (double)qmin/avpkt;

        if (a < 1.0)
                return -1;
        for (wlog=1; wlog<32; wlog++, W /= 2) {
                if (a <= (1 - pow(1-W, burst))/W)
                        return wlog;
        }
        return -1;
}


You can use this to calculate what is wrong. Either burst+1-qmin/avpkt is
smaller than 1, or a is too high to be matched by a time constant.

Regards,

bert

-- 
http://www.PowerDNS.com          Versatile DNS Software & Services
http://www.tk                              the dot in .tk
Netherlabs BV / Rent-a-Nerd.nl           - Nerd Available -
Linux Advanced Routing & Traffic Control: http://ds9a.nl/lartc

_______________________________________________
LARTC mailing list / LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://ds9a.nl/lartc/

Re: [LARTC] RED problem !

[Sumit Pandya]

	Or from my law for implement RED you can go with
# /sbin/tc qdisc add dev <eth0> parent 10:<2000> red max <64000> min 1500 \
limit <64kb> avpkt 1000 burst 20
here,
	parameters in <> are variable and leave rest as it is
	I assume you wana shapping of 64kb
	2000 is id
	parameter to max is (64 * 1000)

-----Original Message-----
From: bert hubert <ahu@ds9a.nl>
To: Arindam Haldar <ahiam@yahoo.com>
Cc: lartc@mailman.ds9a.nl
Subject: Re: [LARTC] RED problem !

On Tue, Jan 01, 2002 at 10:33:06PM +0530, Arindam Haldar wrote:
> hi  all,
> 
> while trying red inplace of sfq/pfifo i go the follwing error
> 
> tc qdisc add dev eth0 parent 1:470 red max 12288 min 6100 limit 12288 
> avpkt 1514 burst 2

This returns -1:

int tc_red_eval_ewma(unsigned qmin, unsigned burst, unsigned avpkt)
{
        int wlog = 1;
        double W = 0.5;
        double a = (double)burst + 1 - (double)qmin/avpkt;

        if (a < 1.0)
                return -1;
        for (wlog=1; wlog<32; wlog++, W /= 2) {
                if (a <= (1 - pow(1-W, burst))/W)
                        return wlog;
        }
        return -1;
}


You can use this to calculate what is wrong. Either burst+1-qmin/avpkt is
smaller than 1, or a is too high to be matched by a time constant.

_______________________________________________
LARTC mailing list / LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://ds9a.nl/lartc/