Query about the working of picoquic_mark_active_stream

[tarundjoshi]

I have modified the sample_server and sample_client provided in the sample folder to do the following :

• The server does nothing but receive data.
• The client has a message pool from which it has to send messages on a single stream to the server.

I am trying to make correct use of the concept of hyperpolling as stated in send_receive_data.md. I have linked the modified sample code. The polling of data seems to stop after sometime even though data is continously sent in every callback or if data is not sent, picoquic_mark_active stream is called within the callback.

The program seems to get stuck when picoquic_mark_active_stream is called within the callback most of the time. Is there anything that is wrong with the way im using picoquic_mark_active_stream ?

sample_client.txt
sample_server.txt

The modified lines in the code are as follows :
Client side code :
51-52, 104-106, 211, 356-384, 510-512, 586
Server side code :
262-297

[huitema]

I looked at your client code. I think the issue is with:

        case picoquic_callback_prepare_to_send:
            if(length < 10){
                /* Don't send if the packet is too small */
                picoquic_mark_active_stream(client_ctx->cnx, stream_ctx->stream_id, 1, stream_ctx);
                break;
            }

This code does not match the recommendation in `send_receive_data.md, which suggests writing:

        case picoquic_callback_prepare_to_send:
            if(length < 10){
                /* Don't send if the packet is too small -- request 0 length buffer, set "still_active" bit. */
                (void)picoquic_provide_stream_data_buffer(bytes, 0, 0, 1);
                break;
            }

[tarundjoshi]

Thank you for your time, i really appreciate it.

The application could also set is_still_active=1, or call picoquic_mark_active_stream from within the call back, which is equivalent.

I am trying to use the picoquic_mark_active_stream from within the callback part in the readme. Aren't both these methods equivalent as stated in the readme ?

If this is not true, then does that mean that repeatedly calling picoquic_mark_active_stream outside the callback and inside behave differently ?

[huitema]

Using "mark active stream" instead of "provide buffer" is somewhat ambiguous, because not linked to the callback context. Please check whether using the recommended method solves your problem.

[tarundjoshi]

I see, so within the callback it is always better to use "provide buffer" to set status of the stream then.

Yes, the recommended method solves this problem, thank you for your time and patience.

[huitema]

Thanks for the feedback. I think we should update the documentation to make the recommendation clearer!