[ENet-discuss] CPU Usage

[Jay Sprenkle]

I assume "rest(1)" is a sleep function? for one second?
If so you're only checking for a key press packet once per second (and only
processing one packet, even if more are waiting).


On Sun, Sep 26, 2010 at 6:30 PM, Nicholas J Ingrassellino <
nick at lifebloodnetworks.com> wrote:

>  I am running a little experiment in C++ using ENet v1.3.0 with MSVC 2k8.
> What I am attempting to create is a pure dumb terminal-style application
> where all video is done on a remote server and sent to the client while the
> client only sends over key presses. Yes, yes, I know; I am reinventing the
> wheel and half the people reading this do not approve. It is just an
> experiment I am doing for kicks.
>
> My issue lies in ENet's CPU usage. I had noticed that during the
> receiving/drawing step my client CPU usage went to 100% and was reacting way
> too slow to do what I want to do. After a while I have narrowed the problem
> down to ENet. I even went as far as taking ENet out of the picture to be
> sure it was not something else using simulated data as if it were received
> from the server (IE virtually not changing my client main loop). Just so I
> have gone on the record as saying it the client, once ENet is removed from
> the picture, can draw an image, pixel by pixel, 60 times a second without
> breaking a sweat.
>
> My server is sending 7 bytes (payload, of course) for each pixel. At
> 800x600x24 I am aware this is a hell of a lot of data but it is still eating
> a lot more CPU than I figured it would on the client. The server gets all
> the data off in a timely fashion but the receiving side can not get it
> nearly as fast as it was sent so it ends up backing up really quickly. The
> client code looks like this:
>
> while ( !main_loop_exit ) {
>     acquire_screen();
>     blit(buffer, screen, 0, 0, 0, 0, buffer->w, buffer->h);
>     release_screen();
>
>     if ( keypressed() ) {
>         unsigned char key_next = readkey() & 0xff;
>         ENetPacket *packet = enet_packet_create(&key_next, sizeof(unsigned
> char), ENET_PACKET_FLAG_RELIABLE);
>         enet_peer_send(peer, 0, packet);
>     }
>
>     if ( enet_host_service(client, &event, 0) > 0 ) {
>         if ( event.type == ENET_EVENT_TYPE_RECEIVE ) {
>             _putpixel24(buffer, ((PACKET_PAYLOAD *)event.packet->data)->x,
> ((PACKET_PAYLOAD *)event.packet->data)->y, makecol(((PACKET_PAYLOAD
> *)event.packet->data)->r, ((PACKET_PAYLOAD *)event.packet->data)->g,
> ((PACKET_PAYLOAD *)event.packet->data)->b));
>             enet_packet_destroy(event.packet);
>         }
>         else if ( event.type == ENET_EVENT_TYPE_DISCONNECT )
>             main_loop_exit = true;
>     }
>     else
>         rest(1);
> }
>
>
>
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