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- // SPDX-License-Identifier: GPL-2.0
- /*
- Description:
- . Disable strace like syscall tracing (--no-syscalls), or try tracing
- just some (-e *sleep).
- . Attach a filter function to a kernel function, returning when it should
- be considered, i.e. appear on the output.
- . Run it system wide, so that any sleep of >= 5 seconds and < than 6
- seconds gets caught.
- . Ask for callgraphs using DWARF info, so that userspace can be unwound
- . While this is running, run something like "sleep 5s".
- . If we decide to add tv_nsec as well, then it becomes:
- int probe(hrtimer_nanosleep, rqtp->tv_sec rqtp->tv_nsec)(void *ctx, int err, long sec, long nsec)
- I.e. add where it comes from (rqtp->tv_nsec) and where it will be
- accessible in the function body (nsec)
- # perf trace --no-syscalls -e tools/perf/examples/bpf/5sec.c/call-graph=dwarf/
- 0.000 perf_bpf_probe:func:(ffffffff9811b5f0) tv_sec=5
- hrtimer_nanosleep ([kernel.kallsyms])
- __x64_sys_nanosleep ([kernel.kallsyms])
- do_syscall_64 ([kernel.kallsyms])
- entry_SYSCALL_64 ([kernel.kallsyms])
- __GI___nanosleep (/usr/lib64/libc-2.26.so)
- rpl_nanosleep (/usr/bin/sleep)
- xnanosleep (/usr/bin/sleep)
- main (/usr/bin/sleep)
- __libc_start_main (/usr/lib64/libc-2.26.so)
- _start (/usr/bin/sleep)
- ^C#
- Copyright (C) 2018 Red Hat, Inc., Arnaldo Carvalho de Melo <acme@redhat.com>
- */
- #include <bpf.h>
- int probe(hrtimer_nanosleep, rqtp->tv_sec)(void *ctx, int err, long sec)
- {
- return sec == 5;
- }
- license(GPL);
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