Eric Lee / smarc-fsl-linux-kernel

25 Aug, 2020

1 commit

  • 3677d0a13   samples: bpf: Refactor kprobe tracing programs with libbpf ... Browse Code »

    For the problem of increasing fragmentation of the bpf loader programs,
    instead of using bpf_loader.o, which is used in samples/bpf, this
    commit refactors the existing kprobe tracing programs with libbbpf
    bpf loader.

    - For kprobe events pointing to system calls, the SYSCALL() macro in
    trace_common.h was used.
    - Adding a kprobe event and attaching a bpf program to it was done
    through bpf_program_attach().
    - Instead of using the existing BPF MAP definition, MAP definition
    has been refactored with the new BTF-defined MAP format.

    Signed-off-by: Daniel T. Lee
    Signed-off-by: Alexei Starovoitov
    Link: https://lore.kernel.org/bpf/20200823085334.9413-3-danieltimlee@gmail.com

    Daniel T. Lee
     

21 Jan, 2020

1 commit

  • 7cf245a37   samples/bpf: Use consistent include paths for libbpf ... Browse Code »

    Fix all files in samples/bpf to include libbpf header files with the bpf/
    prefix, to be consistent with external users of the library. Also ensure
    that all includes of exported libbpf header files (those that are exported
    on 'make install' of the library) use bracketed includes instead of quoted.

    To make sure no new files are introduced that doesn't include the bpf/
    prefix in its include, remove tools/lib/bpf from the include path entirely,
    and use tools/lib instead.

    Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir")
    Signed-off-by: Toke Høiland-Jørgensen
    Signed-off-by: Alexei Starovoitov
    Acked-by: Jesper Dangaard Brouer
    Acked-by: Andrii Nakryiko
    Link: https://lore.kernel.org/bpf/157952560911.1683545.8795966751309534150.stgit@toke.dk

    Toke Høiland-Jørgensen
     

23 Jun, 2015

1 commit

  • 0fb1170ee   bpf: BPF based latency tracing ... Browse Code »

    BPF offers another way to generate latency histograms. We attach
    kprobes at trace_preempt_off and trace_preempt_on and calculate the
    time it takes to from seeing the off/on transition.

    The first array is used to store the start time stamp. The key is the
    CPU id. The second array stores the log2(time diff). We need to use
    static allocation here (array and not hash tables). The kprobes
    hooking into trace_preempt_on|off should not calling any dynamic
    memory allocation or free path. We need to avoid recursivly
    getting called. Besides that, it reduces jitter in the measurement.

    CPU 0
    latency : count distribution
    1 -> 1 : 0 | |
    2 -> 3 : 0 | |
    4 -> 7 : 0 | |
    8 -> 15 : 0 | |
    16 -> 31 : 0 | |
    32 -> 63 : 0 | |
    64 -> 127 : 0 | |
    128 -> 255 : 0 | |
    256 -> 511 : 0 | |
    512 -> 1023 : 0 | |
    1024 -> 2047 : 0 | |
    2048 -> 4095 : 166723 |*************************************** |
    4096 -> 8191 : 19870 |*** |
    8192 -> 16383 : 6324 | |
    16384 -> 32767 : 1098 | |
    32768 -> 65535 : 190 | |
    65536 -> 131071 : 179 | |
    131072 -> 262143 : 18 | |
    262144 -> 524287 : 4 | |
    524288 -> 1048575 : 1363 | |
    CPU 1
    latency : count distribution
    1 -> 1 : 0 | |
    2 -> 3 : 0 | |
    4 -> 7 : 0 | |
    8 -> 15 : 0 | |
    16 -> 31 : 0 | |
    32 -> 63 : 0 | |
    64 -> 127 : 0 | |
    128 -> 255 : 0 | |
    256 -> 511 : 0 | |
    512 -> 1023 : 0 | |
    1024 -> 2047 : 0 | |
    2048 -> 4095 : 114042 |*************************************** |
    4096 -> 8191 : 9587 |** |
    8192 -> 16383 : 4140 | |
    16384 -> 32767 : 673 | |
    32768 -> 65535 : 179 | |
    65536 -> 131071 : 29 | |
    131072 -> 262143 : 4 | |
    262144 -> 524287 : 1 | |
    524288 -> 1048575 : 364 | |
    CPU 2
    latency : count distribution
    1 -> 1 : 0 | |
    2 -> 3 : 0 | |
    4 -> 7 : 0 | |
    8 -> 15 : 0 | |
    16 -> 31 : 0 | |
    32 -> 63 : 0 | |
    64 -> 127 : 0 | |
    128 -> 255 : 0 | |
    256 -> 511 : 0 | |
    512 -> 1023 : 0 | |
    1024 -> 2047 : 0 | |
    2048 -> 4095 : 40147 |*************************************** |
    4096 -> 8191 : 2300 |* |
    8192 -> 16383 : 828 | |
    16384 -> 32767 : 178 | |
    32768 -> 65535 : 59 | |
    65536 -> 131071 : 2 | |
    131072 -> 262143 : 0 | |
    262144 -> 524287 : 1 | |
    524288 -> 1048575 : 174 | |
    CPU 3
    latency : count distribution
    1 -> 1 : 0 | |
    2 -> 3 : 0 | |
    4 -> 7 : 0 | |
    8 -> 15 : 0 | |
    16 -> 31 : 0 | |
    32 -> 63 : 0 | |
    64 -> 127 : 0 | |
    128 -> 255 : 0 | |
    256 -> 511 : 0 | |
    512 -> 1023 : 0 | |
    1024 -> 2047 : 0 | |
    2048 -> 4095 : 29626 |*************************************** |
    4096 -> 8191 : 2704 |** |
    8192 -> 16383 : 1090 | |
    16384 -> 32767 : 160 | |
    32768 -> 65535 : 72 | |
    65536 -> 131071 : 32 | |
    131072 -> 262143 : 26 | |
    262144 -> 524287 : 12 | |
    524288 -> 1048575 : 298 | |

    All this is based on the trace3 examples written by
    Alexei Starovoitov .

    Signed-off-by: Daniel Wagner
    Cc: Alexei Starovoitov
    Cc: Alexei Starovoitov
    Cc: "David S. Miller"
    Cc: Daniel Borkmann
    Cc: Ingo Molnar
    Cc: linux-kernel@vger.kernel.org
    Cc: netdev@vger.kernel.org
    Acked-by: Alexei Starovoitov
    Acked-by: Daniel Borkmann
    Signed-off-by: David S. Miller

    Daniel Wagner