Re: bug in qavg calculation in include/net/red.h (resending as plain-text email)

Le jeudi 05 janvier 2012 à 19:30 +0000, Yalagandula, Praveen a écrit :

(Resending as plain text)

Dear Alexey,

The code (see below) for computing the queue average for RED
implementation in Linux kernel has a bug. The return line should be
"return p->qavg + ((backlog - p->qavg) >> p->Wlog);". 

qavg = qavg*(1-W) + backlog*W

     = qavg + (backlog-qavg)*W

The current buggy code applies right shift to only the previous qavg,
where as it should be applied to (backlog - qavg). Hope you can get
this bug corrected.

Code is correct.

Please read the comment, it really explains the thing.

Thanks