[openib-general] libibcm get events

[Dotan Barak]

Joerg Zinke wrote:
> Hi,
>
> is there a non-blocking alternative for ib_cm_get_event() available? Any
> hints on how to check for events without blocking and waiting for the
> next one?
>
> Regards,
>
> Joerg
>   
Here is a response that Or Gerlitz send a few weeks ago on getting 
completion events in non blocking mode, i think that this can be useful 
in your case too:


"sure, yes, for both questions: the actual object to deliver cq event is 
struct ibv_comp_channel whose only field is a file descriptor with which 
you can implement the requirements, use poll/select to set a timeout, or 
make it non blocking such that you can

    int  rc;
    struct ibv_comp_channel my_ch;
    struct pollfd my_pollfd;

    flags = fcntl(my_ch.fd, F_GETFL)
    rc = fcntl(my_ch.fd, F_SETFL, flags | O_NONBLOCK)

will make ibv_get_event to return immediately if there is no event to 
consume at the channel

    my_pollfd.fd      = my_ch.fd;
    my_pollfd.events  = POLLIN;
    my_pollfd.revents = 0;

    rc = poll(&my_pollfd, 1, ms_timeout);

will allow you to either get a timeout if ms milliseconds have elapsed 
or there is an event waiting for you to consume "


Dotan