Merge pull request #969 from goldshtn/clock-monotonic

Move monotonic_time to BPF class, use CLOCK_MONOTONIC

src/python/bcc/__init__.py

@@ -115,6 +115,30 @@ class BPF(object):
         "linux/netdevice.h": ["sk_buff", "net_device"]
     }
 
+    # BPF timestamps come from the monotonic clock. To be able to filter
+    # and compare them from Python, we need to invoke clock_gettime.
+    # Adapted from http://stackoverflow.com/a/1205762
+    CLOCK_MONOTONIC = 1         # see <linux/time.h>
+
+    class timespec(ct.Structure):
+        _fields_ = [('tv_sec', ct.c_long), ('tv_nsec', ct.c_long)]
+
+    _librt = ct.CDLL('librt.so.1', use_errno=True)
+    _clock_gettime = _librt.clock_gettime
+    _clock_gettime.argtypes = [ct.c_int, ct.POINTER(timespec)]
+
+    @classmethod
+    def monotonic_time(cls):
+        """monotonic_time()
+        Returns the system monotonic time from clock_gettime, using the
+        CLOCK_MONOTONIC constant. The time returned is in nanoseconds.
+        """
+        t = cls.timespec()
+        if cls._clock_gettime(cls.CLOCK_MONOTONIC, ct.pointer(t)) != 0:
+            errno = ct.get_errno()
+            raise OSError(errno, os.strerror(errno))
+        return t.tv_sec * 1e9 + t.tv_nsec
+
     @classmethod
     def generate_auto_includes(cls, program_words):
         """

tools/memleak.py

@@ -16,34 +16,8 @@ from time import sleep
 from datetime import datetime
 import argparse
 import subprocess
-import ctypes
 import os
 
-class Time(object):
-        # BPF timestamps come from the monotonic clock. To be able to filter
-        # and compare them from Python, we need to invoke clock_gettime.
-        # Adapted from http://stackoverflow.com/a/1205762
-        CLOCK_MONOTONIC_RAW = 4         # see <linux/time.h>
-
-        class timespec(ctypes.Structure):
-                _fields_ = [
-                        ('tv_sec', ctypes.c_long),
-                        ('tv_nsec', ctypes.c_long)
-                ]
-
-        librt = ctypes.CDLL('librt.so.1', use_errno=True)
-        clock_gettime = librt.clock_gettime
-        clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)]
-
-        @staticmethod
-        def monotonic_time():
-                t = Time.timespec()
-                if Time.clock_gettime(
-                        Time.CLOCK_MONOTONIC_RAW, ctypes.pointer(t)) != 0:
-                        errno_ = ctypes.get_errno()
-                        raise OSError(errno_, os.strerror(errno_))
-                return t.tv_sec * 1e9 + t.tv_nsec
-
 class KStackDecoder(object):
         def refresh(self):
                 pass
@@ -275,7 +249,7 @@ def print_outstanding():
         allocs = bpf_program["allocs"]
         stack_traces = bpf_program["stack_traces"]
         for address, info in sorted(allocs.items(), key=lambda a: a[1].size):
-                if Time.monotonic_time() - min_age_ns < info.timestamp_ns:
+                if BPF.monotonic_time() - min_age_ns < info.timestamp_ns:
                         continue
                 if info.stack_id < 0:
                         continue

tools/old/memleak.py

@@ -16,34 +16,8 @@ from time import sleep
 from datetime import datetime
 import argparse
 import subprocess
-import ctypes
 import os
 
-class Time(object):
-        # BPF timestamps come from the monotonic clock. To be able to filter
-        # and compare them from Python, we need to invoke clock_gettime.
-        # Adapted from http://stackoverflow.com/a/1205762
-        CLOCK_MONOTONIC_RAW = 4         # see <linux/time.h>
-
-        class timespec(ctypes.Structure):
-                _fields_ = [
-                        ('tv_sec', ctypes.c_long),
-                        ('tv_nsec', ctypes.c_long)
-                ]
-
-        librt = ctypes.CDLL('librt.so.1', use_errno=True)
-        clock_gettime = librt.clock_gettime
-        clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)]
-
-        @staticmethod
-        def monotonic_time():
-                t = Time.timespec()
-                if Time.clock_gettime(
-                        Time.CLOCK_MONOTONIC_RAW, ctypes.pointer(t)) != 0:
-                        errno_ = ctypes.get_errno()
-                        raise OSError(errno_, os.strerror(errno_))
-                return t.tv_sec * 1e9 + t.tv_nsec
-
 class StackDecoder(object):
         def __init__(self, pid):
                 self.pid = pid
@@ -289,7 +263,7 @@ def print_outstanding():
               (datetime.now().strftime("%H:%M:%S"), top_stacks))
         allocs = bpf_program.get_table("allocs")
         for address, info in sorted(allocs.items(), key=lambda a: a[1].size):
-                if Time.monotonic_time() - min_age_ns < info.timestamp_ns:
+                if BPF.monotonic_time() - min_age_ns < info.timestamp_ns:
                         continue
                 stack = decoder.decode_stack(info, kernel_trace)
                 if stack in stacks:

tools/trace.py

@@ -20,31 +20,6 @@ import os
 import traceback
 import sys
 
-class Time(object):
-        # BPF timestamps come from the monotonic clock. To be able to filter
-        # and compare them from Python, we need to invoke clock_gettime.
-        # Adapted from http://stackoverflow.com/a/1205762
-        CLOCK_MONOTONIC_RAW = 4         # see <linux/time.h>
-
-        class timespec(ct.Structure):
-                _fields_ = [
-                        ('tv_sec', ct.c_long),
-                        ('tv_nsec', ct.c_long)
-                ]
-
-        librt = ct.CDLL('librt.so.1', use_errno=True)
-        clock_gettime = librt.clock_gettime
-        clock_gettime.argtypes = [ct.c_int, ct.POINTER(timespec)]
-
-        @staticmethod
-        def monotonic_time():
-                t = Time.timespec()
-                if Time.clock_gettime(
-                        Time.CLOCK_MONOTONIC_RAW, ct.pointer(t)) != 0:
-                        errno_ = ct.get_errno()
-                        raise OSError(errno_, os.strerror(errno_))
-                return t.tv_sec * 1e9 + t.tv_nsec
-
 class Probe(object):
         probe_count = 0
         streq_index = 0
@@ -60,7 +35,7 @@ class Probe(object):
                 cls.max_events = args.max_events
                 cls.print_time = args.timestamp or args.time
                 cls.use_localtime = not args.timestamp
-                cls.first_ts = Time.monotonic_time()
+                cls.first_ts = BPF.monotonic_time()
                 cls.tgid = args.tgid or -1
                 cls.pid = args.pid or -1