Start fixing test_bigmem:

- bigmemtest is replaced by precisionbigmemtest
- add a poor man's watchdog thread to print memory consumption

Lib/test/pickletester.py

@@ -8,7 +8,7 @@ from http.cookies import SimpleCookie
 
 from test.support import (
     TestFailed, TESTFN, run_with_locale,
-    _2G, _4G, precisionbigmemtest,
+    _2G, _4G, bigmemtest,
     )
 
 from pickle import bytes_types
@@ -1159,7 +1159,7 @@ class BigmemPickleTests(unittest.TestCase):
 
     # Binary protocols can serialize longs of up to 2GB-1
 
-    @precisionbigmemtest(size=_2G, memuse=1 + 1, dry_run=False)
+    @bigmemtest(size=_2G, memuse=1 + 1, dry_run=False)
     def test_huge_long_32b(self, size):
         data = 1 << (8 * size)
         try:
@@ -1175,7 +1175,7 @@ class BigmemPickleTests(unittest.TestCase):
     # (older protocols don't have a dedicated opcode for bytes and are
     # too inefficient)
 
-    @precisionbigmemtest(size=_2G, memuse=1 + 1, dry_run=False)
+    @bigmemtest(size=_2G, memuse=1 + 1, dry_run=False)
     def test_huge_bytes_32b(self, size):
         data = b"abcd" * (size // 4)
         try:
@@ -1191,7 +1191,7 @@ class BigmemPickleTests(unittest.TestCase):
         finally:
             data = None
 
-    @precisionbigmemtest(size=_4G, memuse=1 + 1, dry_run=False)
+    @bigmemtest(size=_4G, memuse=1 + 1, dry_run=False)
     def test_huge_bytes_64b(self, size):
         data = b"a" * size
         try:
@@ -1206,7 +1206,7 @@ class BigmemPickleTests(unittest.TestCase):
     # All protocols use 1-byte per printable ASCII character; we add another
     # byte because the encoded form has to be copied into the internal buffer.
 
-    @precisionbigmemtest(size=_2G, memuse=2 + character_size, dry_run=False)
+    @bigmemtest(size=_2G, memuse=2 + character_size, dry_run=False)
     def test_huge_str_32b(self, size):
         data = "abcd" * (size // 4)
         try:
@@ -1223,7 +1223,7 @@ class BigmemPickleTests(unittest.TestCase):
     # BINUNICODE (protocols 1, 2 and 3) cannot carry more than
     # 2**32 - 1 bytes of utf-8 encoded unicode.
 
-    @precisionbigmemtest(size=_4G, memuse=1 + character_size, dry_run=False)
+    @bigmemtest(size=_4G, memuse=1 + character_size, dry_run=False)
     def test_huge_str_64b(self, size):
         data = "a" * size
         try:

Lib/test/support.py

@@ -1053,43 +1053,52 @@ def set_memlimit(limit):
         raise ValueError('Memory limit %r too low to be useful' % (limit,))
     max_memuse = memlimit
 
-def bigmemtest(minsize, memuse):
+def _memory_watchdog(start_evt, finish_evt, period=10.0):
+    """A function which periodically watches the process' memory consumption
+    and prints it out.
+    """
+    # XXX: because of the GIL, and because the very long operations tested
+    # in most bigmem tests are uninterruptible, the loop below gets woken up
+    # much less often than expected.
+    # The polling code should be rewritten in raw C, without holding the GIL,
+    # and push results onto an anonymous pipe.
+    try:
+        page_size = os.sysconf('SC_PAGESIZE')
+    except (ValueError, AttributeError):
+        try:
+            page_size = os.sysconf('SC_PAGE_SIZE')
+        except (ValueError, AttributeError):
+            page_size = 4096
+    procfile = '/proc/{pid}/statm'.format(pid=os.getpid())
+    try:
+        f = open(procfile, 'rb')
+    except IOError as e:
+        warnings.warn('/proc not available for stats: {}'.format(e),
+                      RuntimeWarning)
+        sys.stderr.flush()
+        return
+    with f:
+        start_evt.set()
+        old_data = -1
+        while not finish_evt.wait(period):
+            f.seek(0)
+            statm = f.read().decode('ascii')
+            data = int(statm.split()[5])
+            if data != old_data:
+                old_data = data
+                print(" ... process data size: {data:.1f}G"
+                       .format(data=data * page_size / (1024 ** 3)))
+
+def bigmemtest(size, memuse, dry_run=True):
     """Decorator for bigmem tests.
 
     'minsize' is the minimum useful size for the test (in arbitrary,
     test-interpreted units.) 'memuse' is the number of 'bytes per size' for
     the test, or a good estimate of it.
 
-    The decorator tries to guess a good value for 'size' and passes it to
-    the decorated test function. If minsize * memuse is more than the
-    allowed memory use (as defined by max_memuse), the test is skipped.
-    Otherwise, minsize is adjusted upward to use up to max_memuse.
+    if 'dry_run' is False, it means the test doesn't support dummy runs
+    when -M is not specified.
     """
-    def decorator(f):
-        def wrapper(self):
-            # Retrieve values in case someone decided to adjust them
-            minsize = wrapper.minsize
-            memuse = wrapper.memuse
-            if not max_memuse:
-                # If max_memuse is 0 (the default),
-                # we still want to run the tests with size set to a few kb,
-                # to make sure they work. We still want to avoid using
-                # too much memory, though, but we do that noisily.
-                maxsize = 5147
-                self.assertFalse(maxsize * memuse > 20 * _1M)
-            else:
-                maxsize = int(max_memuse / memuse)
-                if maxsize < minsize:
-                    raise unittest.SkipTest(
-                        "not enough memory: %.1fG minimum needed"
-                        % (minsize * memuse / (1024 ** 3)))
-            return f(self, maxsize)
-        wrapper.minsize = minsize
-        wrapper.memuse = memuse
-        return wrapper
-    return decorator
-
-def precisionbigmemtest(size, memuse, dry_run=True):
     def decorator(f):
         def wrapper(self):
             size = wrapper.size
@@ -1105,7 +1114,28 @@ def precisionbigmemtest(size, memuse, dry_run=True):
                     "not enough memory: %.1fG minimum needed"
                     % (size * memuse / (1024 ** 3)))
 
-            return f(self, maxsize)
+            if real_max_memuse and verbose and threading:
+                print()
+                print(" ... expected peak memory use: {peak:.1f}G"
+                      .format(peak=size * memuse / (1024 ** 3)))
+                sys.stdout.flush()
+                start_evt = threading.Event()
+                finish_evt = threading.Event()
+                t = threading.Thread(target=_memory_watchdog,
+                                     args=(start_evt, finish_evt, 0.5))
+                t.daemon = True
+                t.start()
+                start_evt.set()
+            else:
+                t = None
+
+            try:
+                return f(self, maxsize)
+            finally:
+                if t:
+                    finish_evt.set()
+                    t.join()
+
         wrapper.size = size
         wrapper.memuse = memuse
         return wrapper

Lib/test/test_hashlib.py

@@ -17,7 +17,7 @@ except ImportError:
 import unittest
 import warnings
 from test import support
-from test.support import _4G, precisionbigmemtest
+from test.support import _4G, bigmemtest
 
 # Were we compiled --with-pydebug or with #define Py_DEBUG?
 COMPILED_WITH_PYDEBUG = hasattr(sys, 'gettotalrefcount')
@@ -196,7 +196,7 @@ class HashLibTestCase(unittest.TestCase):
                    b'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789',
                    'd174ab98d277d9f5a5611c2c9f419d9f')
 
-    @precisionbigmemtest(size=_4G + 5, memuse=1)
+    @bigmemtest(size=_4G + 5, memuse=1)
     def test_case_md5_huge(self, size):
         if size == _4G + 5:
             try:
@@ -204,7 +204,7 @@ class HashLibTestCase(unittest.TestCase):
             except OverflowError:
                 pass # 32-bit arch
 
-    @precisionbigmemtest(size=_4G - 1, memuse=1)
+    @bigmemtest(size=_4G - 1, memuse=1)
     def test_case_md5_uintmax(self, size):
         if size == _4G - 1:
             try:

Lib/test/test_xml_etree_c.py

 # xml.etree test for cElementTree
 
 from test import support
-from test.support import precisionbigmemtest, _2G
+from test.support import bigmemtest, _2G
 import unittest
 
 cET = support.import_module('xml.etree.cElementTree')
@@ -35,7 +35,7 @@ def sanity():
 
 class MiscTests(unittest.TestCase):
     # Issue #8651.
-    @support.precisionbigmemtest(size=support._2G + 100, memuse=1)
+    @support.bigmemtest(size=support._2G + 100, memuse=1)
     def test_length_overflow(self, size):
         if size < support._2G + 100:
             self.skipTest("not enough free memory, need at least 2 GB")

Lib/test/test_zlib.py

@@ -3,7 +3,7 @@ from test import support
 import binascii
 import random
 import sys
-from test.support import precisionbigmemtest, _1G, _4G
+from test.support import bigmemtest, _1G, _4G
 
 zlib = support.import_module('zlib')
 
@@ -177,16 +177,16 @@ class CompressTestCase(BaseCompressTestCase, unittest.TestCase):
 
     # Memory use of the following functions takes into account overallocation
 
-    @precisionbigmemtest(size=_1G + 1024 * 1024, memuse=3)
+    @bigmemtest(size=_1G + 1024 * 1024, memuse=3)
     def test_big_compress_buffer(self, size):
         compress = lambda s: zlib.compress(s, 1)
         self.check_big_compress_buffer(size, compress)
 
-    @precisionbigmemtest(size=_1G + 1024 * 1024, memuse=2)
+    @bigmemtest(size=_1G + 1024 * 1024, memuse=2)
     def test_big_decompress_buffer(self, size):
         self.check_big_decompress_buffer(size, zlib.decompress)
 
-    @precisionbigmemtest(size=_4G + 100, memuse=1)
+    @bigmemtest(size=_4G + 100, memuse=1)
     def test_length_overflow(self, size):
         if size < _4G + 100:
             self.skipTest("not enough free memory, need at least 4 GB")
@@ -511,19 +511,19 @@ class CompressObjectTestCase(BaseCompressTestCase, unittest.TestCase):
 
     # Memory use of the following functions takes into account overallocation
 
-    @precisionbigmemtest(size=_1G + 1024 * 1024, memuse=3)
+    @bigmemtest(size=_1G + 1024 * 1024, memuse=3)
     def test_big_compress_buffer(self, size):
         c = zlib.compressobj(1)
         compress = lambda s: c.compress(s) + c.flush()
         self.check_big_compress_buffer(size, compress)
 
-    @precisionbigmemtest(size=_1G + 1024 * 1024, memuse=2)
+    @bigmemtest(size=_1G + 1024 * 1024, memuse=2)
     def test_big_decompress_buffer(self, size):
         d = zlib.decompressobj()
         decompress = lambda s: d.decompress(s) + d.flush()
         self.check_big_decompress_buffer(size, decompress)
 
-    @precisionbigmemtest(size=_4G + 100, memuse=1)
+    @bigmemtest(size=_4G + 100, memuse=1)
     def test_length_overflow(self, size):
         if size < _4G + 100:
             self.skipTest("not enough free memory, need at least 4 GB")