Re: [Myrinet] A problem with GM/MCP event-driven mechanism!

> 1.If the SDMA engine enqueues a send for the SEND engine, The L_send__start_sending_chunk_0/1
>   runs continuesly using the following code:
>     smp = gm.send_chunk[LZERO].smp;
>     #if GM_ENABLE_CRC32
>     smh = gm.send_chunk[LZERO].smh;
>     #endif
>     sml = gm.send_chunk[LZERO].smlt;
>     It seems that the SDMA just stores the send mesg in send_chunk[0]/[1] and sets the 
>   smp/smlt,but it doesn't clear the gm.send_chunk[LZERO].smp/smlt. Then the mesg stored 
>   in send_chunk[0]/[1] are send each time L_send__start_sending_chunk called (that is,the sml  
>   is set) ? It seems impossible, but what's the problem ?
> 

Take a look at the way part of the gm_event_index table is set up. 

      /* send events */
      if (i & SEND_INT_BIT && i & SENDING)
        {
          GM_SET_EVENT_INDEX_FOR_STATE (FINISH_SEND_EVENT, i);
          continue;
        }

This would mean that after the L_send__start_sending_chunk event is 
called, the corresponding L_send__finish_sending_chunk event is 
called. And in L_send__finish_sending_chunk(), the two line of code 

    NOTICE_NOT (SENDING); 
    NOTICE (FREE_SEND_CHUNK); 

ensure that  L_send__start_sending_chunk_0/1() is NOT called without 
the send chunk's smp/smlt being initialized properly. 


> 2. It's said that when the GM_STATE is set using NOTICE_NO(SEND_PENDING), the START_SEND_EVENT
>    cann't happen, and so the L_send__start_sending_chunk_0/1 couldn't be called. 
>    But in our program, after the GM_STATE is set using NOTICE_NO(SEND_PENDING) when the ACK 
>    mesg is received, the START_SEND_EVENT still happens and L_send__start_sending_chunk_0/1 
>    still called. Then what's the problem ?
> 
   Have you traced the various events that are called after the 
NOTICE_NO(SEND_PENDING) is executed? I believe there might a event 
being called which toggles back the SEND_PENDING bit with 
 
    TOGGLE_STATE (gm_free_send_chunk_cnt * SEND_PENDING);

hope that helps, 
Vijay 
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