1. 16 12月, 2016 1 次提交
    • J
      samples/bpf: Make samples more libbpf-centric · d40fc181
      Joe Stringer 提交于
      Switch all of the sample code to use the function names from
      tools/lib/bpf so that they're consistent with that, and to declare their
      own log buffers. This allow the next commit to be purely devoted to
      getting rid of the duplicate library in samples/bpf.
      
      Committer notes:
      
      Testing it:
      
      On a fedora rawhide container, with clang/llvm 3.9, sharing the host
      linux kernel git tree:
      
        # make O=/tmp/build/linux/ headers_install
        # make O=/tmp/build/linux -C samples/bpf/
      
      Since I forgot to make it privileged, just tested it outside the
      container, using what it generated:
      
        # uname -a
        Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux
        # cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/
        # ls -la offwaketime
        -rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime
        # file offwaketime
        offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped
        # readelf -SW offwaketime_kern.o  | grep PROGBITS
        [ 2] .text             PROGBITS        0000000000000000 000040 000000 00  AX  0   0  4
        [ 3] kprobe/try_to_wake_up PROGBITS        0000000000000000 000040 0000d8 00  AX  0   0  8
        [ 5] tracepoint/sched/sched_switch PROGBITS        0000000000000000 000118 000318 00  AX  0   0  8
        [ 7] maps              PROGBITS        0000000000000000 000430 000050 00  WA  0   0  4
        [ 8] license           PROGBITS        0000000000000000 000480 000004 00  WA  0   0  1
        [ 9] version           PROGBITS        0000000000000000 000484 000004 00  WA  0   0  4
        # ./offwaketime | head -5
        swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106
        CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2
        Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5
        firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13
        JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2
        #
      Signed-off-by: NJoe Stringer <joe@ovn.org>
      Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Alexei Starovoitov <ast@fb.com>
      Cc: Daniel Borkmann <daniel@iogearbox.net>
      Cc: Wang Nan <wangnan0@huawei.com>
      Cc: netdev@vger.kernel.org
      Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      d40fc181
  2. 23 6月, 2015 1 次提交
    • D
      bpf: BPF based latency tracing · 0fb1170e
      Daniel Wagner 提交于
      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 <ast@plumgrid.com>.
      Signed-off-by: NDaniel Wagner <daniel.wagner@bmw-carit.de>
      Cc: Alexei Starovoitov <ast@plumgrid.com>
      Cc: Alexei Starovoitov <ast@plumgrid.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Daniel Borkmann <daniel@iogearbox.net>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: linux-kernel@vger.kernel.org
      Cc: netdev@vger.kernel.org
      Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
      Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      0fb1170e