diff options
| author | Donatas Abraitis <donatas.abraitis@gmail.com> | 2021-02-22 22:36:01 +0100 |
|---|---|---|
| committer | Donatas Abraitis <donatas.abraitis@gmail.com> | 2021-02-22 22:36:01 +0100 |
| commit | c952f18422b533adba5cac876db9d43a0701e578 (patch) | |
| tree | dde2f5410a2145cdc3d34e0b2ff90af97c8d68bb /doc | |
| parent | Merge pull request #8105 from donaldsharp/reduce_monotime (diff) | |
| download | frr-c952f18422b533adba5cac876db9d43a0701e578.tar.xz frr-c952f18422b533adba5cac876db9d43a0701e578.zip | |
doc: Instruction how to use Systemtap with FRRouting
Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/developer/tracing.rst | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/doc/developer/tracing.rst b/doc/developer/tracing.rst index c194ae127..b07c71e50 100644 --- a/doc/developer/tracing.rst +++ b/doc/developer/tracing.rst @@ -173,6 +173,77 @@ Example:: When using LTTng, you can also get zlogs as trace events by enabling the ``lttng_ust_tracelog:*`` event class. +To see available SystemTap USDT probes, run:: + + stap -L 'process("/usr/lib/frr/bgpd").mark("*")' + +Example:: + root@host ~> stap -L 'process("/usr/lib/frr/bgpd").mark("*")' + process("/usr/lib/frr/bgpd").mark("capability_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("input_filter") $arg1:long $arg2:long $arg3:long $arg4:long $arg5:long + process("/usr/lib/frr/bgpd").mark("keepalive_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("notification_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("open_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("output_filter") $arg1:long $arg2:long $arg3:long $arg4:long $arg5:long + process("/usr/lib/frr/bgpd").mark("packet_read") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("process_update") $arg1:long $arg2:long $arg3:long $arg4:long $arg5:long $arg6:long + process("/usr/lib/frr/bgpd").mark("refresh_process") $arg1:long $arg2:long + process("/usr/lib/frr/bgpd").mark("update_process") $arg1:long $arg2:long + +When using SystemTap, you can also easily attach to an existing function:: + + stap -L 'process("/usr/lib/frr/bgpd").function("bgp_update_receive")' + +Example: + + root@host ~> stap -L 'process("/usr/lib/frr/bgpd").function("bgp_update_receive")' + process("/usr/lib/frr/bgpd").function("bgp_update_receive@bgpd/bgp_packet.c:1531") $peer:struct peer* $size:bgp_size_t $attr:struct attr $restart:_Bool $nlris:struct bgp_nlri[] $__func__:char const[] const + +Complete ``bgp.stp`` example using SystemTap to show BGP peer, prefix and aspath +using ``process_update`` USDT:: + + global pkt_size; + probe begin + { + ansi_clear_screen(); + println("Starting..."); + } + probe process("/usr/lib/frr/bgpd").function("bgp_update_receive") + { + pkt_size <<< $size; + } + probe process("/usr/lib/frr/bgpd").mark("process_update") + { + aspath = @cast($arg6, "attr")->aspath; + printf("> %s via %s (%s)\n", + user_string($arg2), + user_string(@cast($arg1, "peer")->host), + user_string(@cast(aspath, "aspath")->str)); + } + probe end + { + if (@count(pkt_size)) + print(@hist_linear(pkt_size, 0, 20, 2)); + } + +Output:: + + Starting... + > 192.168.0.0/24 via 192.168.0.1 (65534) + > 192.168.100.1/32 via 192.168.0.1 (65534) + > 172.16.16.1/32 via 192.168.0.1 (65534 65030) + ^Cvalue |-------------------------------------------------- count + 0 | 0 + 2 | 0 + 4 |@ 1 + 6 | 0 + 8 | 0 + ~ + 18 | 0 + 20 | 0 + >20 |@@@@@ 5 + + Concepts -------- |