Python API for BPF perf event

src/python/bcc/__init__.py

@@ -62,13 +62,47 @@ def resolve_name(self, name):
  return -1
  return addr.value
 
+class PerfType:
+ # From perf_type_id in uapi/linux/perf_event.h
+ HARDWARE = 0
+ SOFTWARE = 1
+
+class PerfHWConfig:
+ # From perf_hw_id in uapi/linux/perf_event.h
+ CPU_CYCLES = 0
+ INSTRUCTIONS = 1
+ CACHE_REFERENCES = 2
+ CACHE_MISSES = 3
+ BRANCH_INSTRUCTIONS = 4
+ BRANCH_MISSES = 5
+ BUS_CYCLES = 6
+ STALLED_CYCLES_FRONTEND = 7
+ STALLED_CYCLES_BACKEND = 8
+ REF_CPU_CYCLES = 9
+
+class PerfSWConfig:
+ # From perf_sw_id in uapi/linux/perf_event.h
+ CPU_CLOCK = 0
+ TASK_CLOCK = 1
+ PAGE_FAULTS = 2
+ CONTEXT_SWITCHES = 3
+ CPU_MIGRATIONS = 4
+ PAGE_FAULTS_MIN = 5
+ PAGE_FAULTS_MAJ = 6
+ ALIGNMENT_FAULTS = 7
+ EMULATION_FAULTS = 8
+ DUMMY = 9
+ BPF_OUTPUT = 10
+
 class BPF(object):
+ # From bpf_prog_type in uapi/linux/bpf.h
  SOCKET_FILTER = 1
  KPROBE = 2
  SCHED_CLS = 3
  SCHED_ACT = 4
  TRACEPOINT = 5
  XDP = 6
+ PERF_EVENT = 7
 
  _probe_repl = re.compile("[^a-zA-Z0-9_]")
  _sym_caches = {}
@@ -168,6 +202,7 @@ def __init__(self, src_file="", hdr_file="", text=None, cb=None, debug=0,
  self.open_kprobes = {}
  self.open_uprobes = {}
  self.open_tracepoints = {}
+ self.open_perf_events = {}
  self.tracefile = None
  atexit.register(self.cleanup)
 
@@ -608,6 +643,41 @@ def detach_tracepoint(self, tp=""):
  raise Exception("Failed to detach BPF from tracepoint")
  del self.open_tracepoints[tp]
 
+ def _attach_perf_event(self, progfd, ev_type, ev_config,
+ sample_period, sample_freq, pid, cpu, group_fd):
+ res = lib.bpf_attach_perf_event(progfd, ev_type, ev_config,
+ sample_period, sample_freq, pid, cpu, group_fd)
+ if res < 0:
+ raise Exception("Failed to attach BPF to perf event")
+ return res
+
+ def attach_perf_event(self, ev_type=-1, ev_config=-1, fn_name="",
+ sample_period=0, sample_freq=0, pid=-1, cpu=-1, group_fd=-1):
+ fn = self.load_func(fn_name, BPF.PERF_EVENT)
+ res = {}
+ if cpu >= 0:
+ res[cpu] = self._attach_perf_event(fn.fd, ev_type, ev_config,
+ sample_period, sample_freq, pid, cpu, group_fd)
+ else:
+ for i in range(0, multiprocessing.cpu_count()):
+ res[i] = self._attach_perf_event(fn.fd, ev_type, ev_config,
+ sample_period, sample_freq, pid, i, group_fd)
+ self.open_perf_events[(ev_type, ev_config)] = res
+
+ def detach_perf_event(self, ev_type=-1, ev_config=-1):
+ try:
+ fds = self.open_perf_events[(ev_type, ev_config)]
+ except KeyError:
+ raise Exception("Perf event type {} config {} not attached".format(
+ ev_type, ev_config))
+ for fd in fds.values():
+ os.close(fd)
+ res = lib.bpf_detach_perf_event(ev_type, ev_config)
+ if res < 0:
+ raise Exception("Failed to detach BPF from perf event")
+ del self.open_perf_events[(ev_type, ev_config)]
+ return res
+
  def _add_uprobe(self, name, probe):
  global _num_open_probes
  self.open_uprobes[name] = probe
@@ -975,6 +1045,8 @@ def cleanup(self):
  (tp_category, tp_name) = k.split(':')
  lib.bpf_detach_tracepoint(tp_category, tp_name)
  self.open_tracepoints.clear()
+ for (ev_type, ev_config) in list(self.open_perf_events.keys()):
+ self.detach_perf_event(ev_type, ev_config)
  if self.tracefile:
  self.tracefile.close()
 

src/python/bcc/libbcc.py

@@ -113,6 +113,12 @@
 lib.bpf_attach_xdp.restype = ct.c_int;
 lib.bpf_attach_xdp.argtypes = [ct.c_char_p, ct.c_int]
 
+lib.bpf_attach_perf_event.restype = ct.c_int;
+lib.bpf_attach_perf_event.argtype = [ct.c_int, ct.c_uint, ct.c_uint, ct.c_ulonglong, ct.c_ulonglong,
+ ct.c_int, ct.c_int, ct.c_int]
+lib.bpf_detach_perf_event.restype = ct.c_int;
+lib.bpf_detach_perf_event.argtype = [ct.c_uint, ct.c_uint]
+
 # bcc symbol helpers
 class bcc_symbol(ct.Structure):
  _fields_ = [