WIP FPC-III support
[linux/fpc-iii.git] / tools / perf / examples / bpf / 5sec.c
blob65c4ff6892d967ab02459ba14f258d7080d6e078
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 Description:
5 . Disable strace like syscall tracing (--no-syscalls), or try tracing
6 just some (-e *sleep).
8 . Attach a filter function to a kernel function, returning when it should
9 be considered, i.e. appear on the output.
11 . Run it system wide, so that any sleep of >= 5 seconds and < than 6
12 seconds gets caught.
14 . Ask for callgraphs using DWARF info, so that userspace can be unwound
16 . While this is running, run something like "sleep 5s".
18 . If we decide to add tv_nsec as well, then it becomes:
20 int probe(hrtimer_nanosleep, rqtp->tv_sec rqtp->tv_nsec)(void *ctx, int err, long sec, long nsec)
22 I.e. add where it comes from (rqtp->tv_nsec) and where it will be
23 accessible in the function body (nsec)
25 # perf trace --no-syscalls -e tools/perf/examples/bpf/5sec.c/call-graph=dwarf/
26 0.000 perf_bpf_probe:func:(ffffffff9811b5f0) tv_sec=5
27 hrtimer_nanosleep ([kernel.kallsyms])
28 __x64_sys_nanosleep ([kernel.kallsyms])
29 do_syscall_64 ([kernel.kallsyms])
30 entry_SYSCALL_64 ([kernel.kallsyms])
31 __GI___nanosleep (/usr/lib64/libc-2.26.so)
32 rpl_nanosleep (/usr/bin/sleep)
33 xnanosleep (/usr/bin/sleep)
34 main (/usr/bin/sleep)
35 __libc_start_main (/usr/lib64/libc-2.26.so)
36 _start (/usr/bin/sleep)
37 ^C#
39 Copyright (C) 2018 Red Hat, Inc., Arnaldo Carvalho de Melo <acme@redhat.com>
42 #include <bpf/bpf.h>
44 #define NSEC_PER_SEC 1000000000L
46 int probe(hrtimer_nanosleep, rqtp)(void *ctx, int err, long long sec)
48 return sec / NSEC_PER_SEC == 5ULL;
51 license(GPL);