samples/bpf: Add counting example for kfree_skb() function calls and the write() syscall
this example has two probes in one C file that attach to
different kprove events and use two different maps.
1st probe is x64 specific equivalent of dropmon. It attaches to
kfree_skb, retrevies 'ip' address of kfree_skb() caller and
counts number of packet drops at that 'ip' address. User space
prints 'location - count' map every second.
2nd probe attaches to kprobe:sys_write and computes a histogram
of different write sizes
Usage:
$ sudo tracex2
location 0xffffffff81695995 count 1
location 0xffffffff816d0da9 count 2
location 0xffffffff81695995 count 2
location 0xffffffff816d0da9 count 2
location 0xffffffff81695995 count 3
location 0xffffffff816d0da9 count 2
557145+0 records in
557145+0 records out
285258240 bytes (285 MB) copied, 1.02379 s, 279 MB/s
syscall write() stats
byte_size : count distribution
1 -> 1 : 3 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 2 | |
32 -> 63 : 3 | |
64 -> 127 : 1 | |
128 -> 255 : 1 | |
256 -> 511 : 0 | |
512 -> 1023 : 1118968 |************************************* |
Ctrl-C at any time. Kernel will auto cleanup maps and programs
$ addr2line -ape ./bld_x64/vmlinux 0xffffffff81695995
0xffffffff816d0da9 0xffffffff81695995:
./bld_x64/../net/ipv4/icmp.c:1038 0xffffffff816d0da9:
./bld_x64/../net/unix/af_unix.c:1231
Signed-off-by: Alexei Starovoitov <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
3 files changed
