On 2016/2/24 23:19, Arnaldo Carvalho de Melo wrote:
Em Wed, Feb 24, 2016 at 11:20:45AM +0000, Wang Nan escreveu:
This patch allows 'perf script' output messages from BPF program.
For example, use test_bpf_output_3.c at the end of this commit
message,
# ./perf record -e bpf-output/no-inherit,name=evt/ \
-e ./test_bpf_output_3.c/map:channel.event=evt/ \
usleep 100000
Trying to test this with 'perf trace', i.e. to shortcircuit record +
analysis:
[root@jouet bpf]# perf trace -a --ev bpf-output/no-inherit,name=evt/ --ev
./test_bpf_output_3.c/map:channel.event=evt/ --ev 'perf_bpf_probe:*' usleep
100000
Failed to set filter "common_pid != 23954" on event evt with 22 (Invalid
argument)
Can't we set tracepoint filters on these events?
No we can't. filters can only be set to tracepoint events, but
bpf-output is a
software event.
In addition, you don't need
... --ev 'perf_bpf_probe:*' ...
because they should be already collected by '--ev ./test_bpf_output_3.c'.
You don't see them because the two kprobe events are filtered out by BPF
program.
See 'return 0' in func.
Thank you.
