[Cake] Fw: Choosing a tin to work on

[George Amanakis <g_amanakis@yahoo.com>]

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Hi Jonathan,

I have some questions regarding the algorithm to choose a tin to dequeue from in sch_cake.c:-----------8<------------
        int oi, best_tin=0;
        s64 best_time = 0xFFFFFFFFFFFFUL;

        for(oi=0; oi < q->tin_cnt; oi++) {
            int tin = q->tin_order[oi];
            b = q->tins + tin;
            if((b->sparse_flow_count + b->bulk_flow_count) > 0) {
                s64 tdiff = b->tin_time_next_packet - now;
                if(tdiff <= 0 || tdiff <= best_time) {
                    best_time = tdiff;
                    best_tin = tin;
                }
            }
        }
-----------8<------------

1) best_time is defined as a positive signed integer, this equals to 78 hours if I did the calculations right. Why did you choose this? Did you mean to define it as "-1"?
2) If you meant to define it as "-1", the condition " tdiff <= best_time" would not matter. I can see no case where " tdiff > 0" and " tdiff <= best_time".

Could you shed some light into this?

Thank you,
George






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