[clearview-discuss] dld_tx_enqueue() and TCP performance

[Cathy Zhou]

Peter Memishian wrote:
>  > I don't think either of the above is correct. Note that once the message 
>  > size reaches the threshold, mp should be the first one needs to be freed, 
>  > the the previous message should be set as dsp->ds_tx_list_tail.
> 
> I'm not sure it really matters, but if you think so, then you can keep the
> pointer to the previous message.  Just please don't unroll the first
> iteration of the loop -- that really made the code ugly.
> 
Okay. I've changed the code to:

         /* Calculate total size and count of the packet(s) */
         cnt = msgcnt = 0;
         for (prev = NULL, mp = dsp->ds_tx_list_head; mp != NULL;
             prev = mp, mp = mp->b_next) {
                 size = mp_getsize(mp);
                 cnt += size;
                 msgcnt ++;
                 if ((cnt >= dld_max_q_count || msgcnt >= dld_max_q_count)) {
                         ASSERT(dsp->ds_tx_qbusy);
                         dsp->ds_tx_list_tail = prev;
                         if (prev == NULL)
                                 dsp->ds_tx_list_head = NULL;
                         else
                                 prev->b_next = NULL;
                         freemsgchain(mp);
                         cnt -= size;
                         msgcnt --;
                         break;
                 }
         }