• Arnaldo Carvalho de Melo's avatar
    perf bpf: Add probe() helper to reduce kprobes boilerplate · d8fc764d
    Arnaldo Carvalho de Melo authored
    So that kprobe definitions become:
      int probe(function, variables)(void *ctx, int err, var1, var2, ...)
    The existing 5sec.c, got converted and goes from:
      SEC("func=hrtimer_nanosleep rqtp->tv_sec")
      int func(void *ctx, int err, long sec)
      int probe(hrtimer_nanosleep, rqtp->tv_sec)(void *ctx, int err, long sec)
    If we decide to add tv_nsec as well, then it becomes:
      $ cat tools/perf/examples/bpf/5sec.c
      #include <bpf.h>
      int probe(hrtimer_nanosleep, rqtp->tv_sec rqtp->tv_nsec)(void *ctx, int err, long sec, long nsec)
    	  return sec == 5;
    And if we run it, system wide as before and run some 'sleep' with values
    for the tv_nsec field, we get:
      # perf trace --no-syscalls -e tools/perf/examples/bpf/5sec.c
         0.000 perf_bpf_probe:hrtimer_nanosleep:(ffffffff9811b5f0) tv_sec=5 tv_nsec=100000000
      9641.650 perf_bpf_probe:hrtimer_nanosleep:(ffffffff9811b5f0) tv_sec=5 tv_nsec=123450001
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: David Ahern <dsahern@gmail.com>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Wang Nan <wangnan0@huawei.com>
    Link: https://lkml.kernel.org/n/tip-1v9r8f6ds5av0w9pcwpeknyl@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
5sec.c 1.9 KB