// 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/bpf.h> #define NSEC_PER_SEC 1000000000L int probe(hrtimer_nanosleep, rqtp)(void *ctx, int err, long long sec) { return sec / NSEC_PER_SEC == 5ULL; } license(GPL);