// backlog.stp

global syn_stat, acc_stat
global syn_total, acc_total

probe begin {
    println("Tracing...Hit Ctl-C to exit.")
}

probe kernel.function("tcp_v4_conn_request") {
    qlen = @cast($sk, "struct inet_connection_sock")->icsk_accept_queue->listen_opt->qlen
    //max_qlen_log = @cast($sk, "struct inet_connection_sock")->icsk_accept_queue->listen_opt->max_qlen_log
    sk_ack_backlog = $sk->sk_ack_backlog
    //sk_max_ack_backlog = $sk->sk_max_ack_backlog
    syn_stat <<< qlen
    acc_stat <<< sk_ack_backlog
    syn_total++
    acc_total++
    /*
    println("Syn-Q cur: ", qlen, " Syn-Q max: ", max_qlen_log,
            " Acc-Q cur: ", sk_ack_backlog, " Acc-Q max: ", sk_max_ack_backlog)
            */
}

probe timer.ms(1000) {
    if(@count(syn_stat)>0) {
        println("=== Syn-Q ===")
        println("min/avg/max: ", @min(syn_stat), "/", @avg(syn_stat), "/", @max(syn_stat))
        println("total num: ", syn_total)
        println(@hist_log(syn_stat))
        println("=== Acc-Q ===")
        println("min/avg/max: ", @min(acc_stat), "/", @avg(acc_stat), "/", @max(acc_stat))
        println("total num: ", acc_total)
        println(@hist_log(acc_stat))
    }
}