[dtrace-discuss] DTrace: Printing pid of the process when tcpListenDrop is incremented

[Amer Ather]

IHAC who is seeing high number of tcpListenDrop events. There are
multiple servers are running on the system. He likes to know the pid of
the process that has its listen backlog full and responsible for
triggering the tcpListenDrop event. tcpListenDrop counter is logged in


tcp_conn_request(void *arg, mblk_t *mp, void *arg2)
{
....
if (tcp->tcp_conn_req_cnt_q >= tcp->tcp_conn_req_max) {
                mutex_exit(&tcp->tcp_eager_lock);
                TCP_STAT(tcp_listendrop);  <<<<<<
                BUMP_MIB(&tcp_mib, tcpListenDrop);
...
}

My question is how one can get pid from conn_t or tcp_t structure so
that we know which process backlog size execeeds the max size.

#!/usr/sbin/dtrace -s

#pragma D option quiet

fbt:ip:tcp_conn_request:entry
{
        self->connp = (conn_t *)arg0;
        self->tcp   = (tcp_t *)self->connp->conn_tcp;


@backlog[self->tcp->tcp_conn_req_cnt_q,self->tcp->tcp_conn_req_max]=count();

printf("\ntcp_conn_req_cnt_q: %d\n", self->tcp->tcp_conn_req_cnt_q);
printf("\ntcp_conn_req_max: %d\n", self->tcp->tcp_conn_req_max);

}

Thanks,
-- 
Amer Ather	
PTS-KERNEL     			
amer.ather at Sun.COM		
408-276-9780 (x19780)				
Pager: 888-242-1324
email-pager: 8882421324 at archwireless.net

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