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51 lines
2.0 KiB
51 lines
2.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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Description: |
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. Disable strace like syscall tracing (--no-syscalls), or try tracing |
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just some (-e *sleep). |
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. Attach a filter function to a kernel function, returning when it should |
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be considered, i.e. appear on the output. |
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. Run it system wide, so that any sleep of >= 5 seconds and < than 6 |
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seconds gets caught. |
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. Ask for callgraphs using DWARF info, so that userspace can be unwound |
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. While this is running, run something like "sleep 5s". |
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. If we decide to add tv_nsec as well, then it becomes: |
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int probe(hrtimer_nanosleep, rqtp->tv_sec rqtp->tv_nsec)(void *ctx, int err, long sec, long nsec) |
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I.e. add where it comes from (rqtp->tv_nsec) and where it will be |
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accessible in the function body (nsec) |
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# perf trace --no-syscalls -e tools/perf/examples/bpf/5sec.c/call-graph=dwarf/ |
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0.000 perf_bpf_probe:func:(ffffffff9811b5f0) tv_sec=5 |
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hrtimer_nanosleep ([kernel.kallsyms]) |
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__x64_sys_nanosleep ([kernel.kallsyms]) |
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do_syscall_64 ([kernel.kallsyms]) |
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entry_SYSCALL_64 ([kernel.kallsyms]) |
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__GI___nanosleep (/usr/lib64/libc-2.26.so) |
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rpl_nanosleep (/usr/bin/sleep) |
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xnanosleep (/usr/bin/sleep) |
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main (/usr/bin/sleep) |
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__libc_start_main (/usr/lib64/libc-2.26.so) |
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_start (/usr/bin/sleep) |
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^C# |
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Copyright (C) 2018 Red Hat, Inc., Arnaldo Carvalho de Melo <[email protected]> |
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*/ |
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#include <bpf.h> |
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#define NSEC_PER_SEC 1000000000L |
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int probe(hrtimer_nanosleep, rqtp)(void *ctx, int err, long long sec) |
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{ |
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return sec / NSEC_PER_SEC == 5ULL; |
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} |
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license(GPL);
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