[diffoscope] 02/03: Print top memory allocations when receiving USR1

[Jérémy Bobbio]

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lunar pushed a commit to branch master
in repository diffoscope.

commit 4530f664a0cf6e9cef13b3b0bc9f7bcdd23144b9
Author: Jérémy Bobbio <lunar at debian.org>
Date:   Tue Dec 22 13:57:56 2015 +0000

    Print top memory allocations when receiving USR1
    
    In order to debug the current large memory requirements, we implement
    support for displaying top memory allocations when receiving the USR1 signal.
    The code comes from the Python documentation for the tracemalloc module.
---
 diffoscope/__main__.py | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/diffoscope/__main__.py b/diffoscope/__main__.py
index ac7913c..09382af 100644
--- a/diffoscope/__main__.py
+++ b/diffoscope/__main__.py
@@ -20,12 +20,14 @@
 
 import argparse
 from contextlib import contextmanager
+import linecache
 import logging
 import codecs
 import os
 import signal
 import sys
 import traceback
+import tracemalloc
 try:
     import tlsh
 except ImportError:
@@ -162,18 +164,53 @@ def run_diffoscope(parsed_args):
     return 0
 
 
+def display_top(snapshot, group_by='lineno', limit=10):
+    snapshot = snapshot.filter_traces((
+        tracemalloc.Filter(False, "<frozen importlib._bootstrap>"),
+        tracemalloc.Filter(False, "<unknown>"),
+    ))
+    top_stats = snapshot.statistics(group_by)
+
+    logger.debug("Top %s lines", limit)
+    for index, stat in enumerate(top_stats[:limit], 1):
+        frame = stat.traceback[0]
+        # replace "/path/to/module/file.py" with "module/file.py"
+        filename = os.sep.join(frame.filename.split(os.sep)[-2:])
+        logger.debug("#%s: %s:%s: %.1f KiB",
+                     index, filename, frame.lineno, stat.size / 1024)
+        line = linecache.getline(frame.filename, frame.lineno).strip()
+        if line:
+            logger.debug('    %s', line)
+
+    other = top_stats[limit:]
+    if other:
+        size = sum(stat.size for stat in other)
+        logger.debug("%s other: %.1f KiB", len(other), size / 1024)
+    total = sum(stat.size for stat in top_stats)
+    logger.debug("Total allocated size: %.1f KiB", total / 1024)
+
+
 def sigterm_handler(signo, stack_frame):
     sys.exit(2)
 
 
+def sigusr1_handler(signo, stack_frame):
+    logger.debug('got SIGUSR1')
+    snapshot = tracemalloc.take_snapshot()
+    logger.debug('display_top')
+    display_top(snapshot)
+
+
 def main(args=None):
     if args is None:
         args = sys.argv[1:]
     signal.signal(signal.SIGTERM, sigterm_handler)
+    signal.signal(signal.SIGUSR1, sigusr1_handler)
     parsed_args = None
     try:
         parser = create_parser()
         parsed_args = parser.parse_args(args)
+        tracemalloc.start()
         sys.exit(run_diffoscope(parsed_args))
     except KeyboardInterrupt:
         logger.info('Keyboard Interrupt')

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