NAME
dtrace_mib – a DTrace provider for Management Information Base
SYNOPSIS
mib:module:count:counter
In config(5): options KDTRACE_MIB_SDT
DESCRIPTION
The mib provider allows tracing of Management Information Base stats counters.
The list of instrumented modules includes:
- ah
-
IP Authentication Header (RFC 2402), ipsec(4)
- esp
-
IP Encapsulating Security Payload (RFC 1827, RFC 2406), ipsec(4)
- icmp
- icmp6
- ip
- ip6
- ipcomp
-
IP Payload Compression Protocol, ipsec(4)
- ipsec
- tcp
- udp
The mib:module:count:counter probes fire when the counter in modules increases.
The first probe argument, uint64_t args[0], is the increment that the counter will increase by.
Note that some probes like mib:esp:count:esps_hist or mib:icmp6:count:icp6s_outhist provide additional probe-specific arguments.
EXAMPLES
Example 1 : Tracing IP Stats Counters
When debugging network issues one common clue is an unexpectedly incrementing error counter. This is helpful, in that it gives us an idea of what might be going wrong, but often these counters may be incremented in different functions.
Trace all mib probes in the ip(4) module and print the current count and a stack trace:
# dtrace -n 'mib:ip:count: { printf("%d", arg0); stack(); }'
dtrace: description 'mib:ip:count: ' matched 29 probes
CPU ID FUNCTION:NAME
7 98784 count:ips_localout 1
kernel`ip_output+0x17a2
kernel`udp_send+0xaca
kernel`sosend_dgram+0x315
kernel`sousrsend+0x79
kernel`kern_sendit+0x1be
kernel`sendit+0x1ab
kernel`sys_sendmsg+0x5b
kernel`amd64_syscall+0x169
kernel`0xffffffff81094b8b
SEE ALSO
dtrace(1), dtrace_ip(4), dtrace_tcp(4), dtrace_udp(4), tracing(7), sysctl(8)
STANDARDS
The probe descriptions in the FreeBSD mib provider are not compatible with those in the Solaris/illumos mib provider.
AUTHORS
The mib provider was added to FreeBSD by Kristof Provost ⟨[email protected]⟩.
This manual page was written by Mateusz Piotrowski ⟨[email protected]⟩.