author | Shane McErlean <shane.mcerlean@accenture.com> |
Fri, 27 Aug 2010 15:33:49 +0100 | |
changeset 101 | 1e82a8be084a |
parent 1 | 2fb8b9db1c86 |
permissions | -rw-r--r-- |
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This file describes some special Python build types enabled via |
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compile-time preprocessor defines. |
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It is best to define these options in the EXTRA_CFLAGS make variable; |
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``make EXTRA_CFLAGS="-DPy_REF_DEBUG"``. |
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--------------------------------------------------------------------------- |
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Py_REF_DEBUG introduced in 1.4 |
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named REF_DEBUG before 1.4 |
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Turn on aggregate reference counting. This arranges that extern |
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_Py_RefTotal hold a count of all references, the sum of ob_refcnt across |
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all objects. In a debug-mode build, this is where the "8288" comes from |
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in |
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>>> 23 |
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23 |
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[8288 refs] |
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>>> |
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Note that if this count increases when you're not storing away new objects, |
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there's probably a leak. Remember, though, that in interactive mode the |
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special name "_" holds a reference to the last result displayed! |
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Py_REF_DEBUG also checks after every decref to verify that the refcount |
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hasn't gone negative, and causes an immediate fatal error if it has. |
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Special gimmicks: |
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sys.gettotalrefcount() |
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Return current total of all refcounts. |
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Available under Py_REF_DEBUG in Python 2.3. |
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Before 2.3, Py_TRACE_REFS was required to enable this function. |
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--------------------------------------------------------------------------- |
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Py_TRACE_REFS introduced in 1.4 |
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named TRACE_REFS before 1.4 |
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Turn on heavy reference debugging. This is major surgery. Every PyObject |
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grows two more pointers, to maintain a doubly-linked list of all live |
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heap-allocated objects. Most builtin type objects are not in this list, |
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as they're statically allocated. Starting in Python 2.3, if COUNT_ALLOCS |
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(see below) is also defined, a static type object T does appear in this |
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list if at least one object of type T has been created. |
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Note that because the fundamental PyObject layout changes, Python modules |
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compiled with Py_TRACE_REFS are incompatible with modules compiled without |
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it. |
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Py_TRACE_REFS implies Py_REF_DEBUG. |
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Special gimmicks: |
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sys.getobjects(max[, type]) |
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Return list of the (no more than) max most-recently allocated objects, |
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most recently allocated first in the list, least-recently allocated |
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last in the list. max=0 means no limit on list length. |
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If an optional type object is passed, the list is also restricted to |
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objects of that type. |
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The return list itself, and some temp objects created just to call |
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sys.getobjects(), are excluded from the return list. Note that the |
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list returned is just another object, though, so may appear in the |
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return list the next time you call getobjects(); note that every |
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object in the list is kept alive too, simply by virtue of being in |
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the list. |
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envar PYTHONDUMPREFS |
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If this envar exists, Py_Finalize() arranges to print a list of |
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all still-live heap objects. This is printed twice, in different |
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formats, before and after Py_Finalize has cleaned up everything it |
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can clean up. The first output block produces the repr() of each |
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object so is more informative; however, a lot of stuff destined to |
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die is still alive then. The second output block is much harder |
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to work with (repr() can't be invoked anymore -- the interpreter |
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has been torn down too far), but doesn't list any objects that will |
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die. The tool script combinerefs.py can be run over this to combine |
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the info from both output blocks. The second output block, and |
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combinerefs.py, were new in Python 2.3b1. |
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--------------------------------------------------------------------------- |
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PYMALLOC_DEBUG introduced in 2.3 |
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80 |
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When pymalloc is enabled (WITH_PYMALLOC is defined), calls to the PyObject_ |
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memory routines are handled by Python's own small-object allocator, while |
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calls to the PyMem_ memory routines are directed to the system malloc/ |
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realloc/free. If PYMALLOC_DEBUG is also defined, calls to both PyObject_ |
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and PyMem_ memory routines are directed to a special debugging mode of |
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Python's small-object allocator. |
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87 |
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This mode fills dynamically allocated memory blocks with special, |
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recognizable bit patterns, and adds debugging info on each end of |
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dynamically allocated memory blocks. The special bit patterns are: |
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91 |
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#define CLEANBYTE 0xCB /* clean (newly allocated) memory */ |
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#define DEADBYTE 0xDB /* dead (newly freed) memory */ |
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#define FORBIDDENBYTE 0xFB /* forbidden -- untouchable bytes */ |
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95 |
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Strings of these bytes are unlikely to be valid addresses, floats, or 7-bit |
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ASCII strings. |
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98 |
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Let S = sizeof(size_t). 2*S bytes are added at each end of each block of N |
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bytes requested. The memory layout is like so, where p represents the |
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address returned by a malloc-like or realloc-like function (p[i:j] means |
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the slice of bytes from *(p+i) inclusive up to *(p+j) exclusive; note that |
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the treatment of negative indices differs from a Python slice): |
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105 |
p[-2*S:-S] |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
106 |
Number of bytes originally asked for. This is a size_t, big-endian |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
107 |
(easier to read in a memory dump). |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
108 |
p[-S:0] |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
109 |
Copies of FORBIDDENBYTE. Used to catch under- writes and reads. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
110 |
p[0:N] |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
111 |
The requested memory, filled with copies of CLEANBYTE, used to catch |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
112 |
reference to uninitialized memory. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
113 |
When a realloc-like function is called requesting a larger memory |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
114 |
block, the new excess bytes are also filled with CLEANBYTE. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
115 |
When a free-like function is called, these are overwritten with |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
116 |
DEADBYTE, to catch reference to freed memory. When a realloc- |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
117 |
like function is called requesting a smaller memory block, the excess |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
118 |
old bytes are also filled with DEADBYTE. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
119 |
p[N:N+S] |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
120 |
Copies of FORBIDDENBYTE. Used to catch over- writes and reads. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
121 |
p[N+S:N+2*S] |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
122 |
A serial number, incremented by 1 on each call to a malloc-like or |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
123 |
realloc-like function. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
124 |
Big-endian size_t. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
125 |
If "bad memory" is detected later, the serial number gives an |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
126 |
excellent way to set a breakpoint on the next run, to capture the |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
127 |
instant at which this block was passed out. The static function |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
128 |
bumpserialno() in obmalloc.c is the only place the serial number |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
129 |
is incremented, and exists so you can set such a breakpoint easily. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
130 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
131 |
A realloc-like or free-like function first checks that the FORBIDDENBYTEs |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
132 |
at each end are intact. If they've been altered, diagnostic output is |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
133 |
written to stderr, and the program is aborted via Py_FatalError(). The |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
134 |
other main failure mode is provoking a memory error when a program |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
135 |
reads up one of the special bit patterns and tries to use it as an address. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
136 |
If you get in a debugger then and look at the object, you're likely |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
137 |
to see that it's entirely filled with 0xDB (meaning freed memory is |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
138 |
getting used) or 0xCB (meaning uninitialized memory is getting used). |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
139 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
140 |
Note that PYMALLOC_DEBUG requires WITH_PYMALLOC. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
141 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
142 |
Special gimmicks: |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
143 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
144 |
envar PYTHONMALLOCSTATS |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
145 |
If this envar exists, a report of pymalloc summary statistics is |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
146 |
printed to stderr whenever a new arena is allocated, and also |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
147 |
by Py_Finalize(). |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
148 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
149 |
Changed in 2.5: The number of extra bytes allocated is 4*sizeof(size_t). |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
150 |
Before it was 16 on all boxes, reflecting that Python couldn't make use of |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
151 |
allocations >= 2**32 bytes even on 64-bit boxes before 2.5. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
152 |
--------------------------------------------------------------------------- |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
153 |
Py_DEBUG introduced in 1.5 |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
154 |
named DEBUG before 1.5 |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
155 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
156 |
This is what is generally meant by "a debug build" of Python. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
157 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
158 |
Py_DEBUG implies LLTRACE, Py_REF_DEBUG, Py_TRACE_REFS, and |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
159 |
PYMALLOC_DEBUG (if WITH_PYMALLOC is enabled). In addition, C |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
160 |
assert()s are enabled (via the C way: by not defining NDEBUG), and |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
161 |
some routines do additional sanity checks inside "#ifdef Py_DEBUG" |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
162 |
blocks. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
163 |
--------------------------------------------------------------------------- |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
164 |
COUNT_ALLOCS introduced in 0.9.9 |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
165 |
partly broken in 2.2 and 2.2.1 |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
166 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
167 |
Each type object grows three new members: |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
168 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
169 |
/* Number of times an object of this type was allocated. */ |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
170 |
int tp_allocs; |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
171 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
172 |
/* Number of times an object of this type was deallocated. */ |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
173 |
int tp_frees; |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
174 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
175 |
/* Highwater mark: the maximum value of tp_allocs - tp_frees so |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
176 |
* far; or, IOW, the largest number of objects of this type alive at |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
177 |
* the same time. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
178 |
*/ |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
179 |
int tp_maxalloc; |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
180 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
181 |
Allocation and deallocation code keeps these counts up to date. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
182 |
Py_Finalize() displays a summary of the info returned by sys.getcounts() |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
183 |
(see below), along with assorted other special allocation counts (like |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
184 |
the number of tuple allocations satisfied by a tuple free-list, the number |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
185 |
of 1-character strings allocated, etc). |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
186 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
187 |
Before Python 2.2, type objects were immortal, and the COUNT_ALLOCS |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
188 |
implementation relies on that. As of Python 2.2, heap-allocated type/ |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
189 |
class objects can go away. COUNT_ALLOCS can blow up in 2.2 and 2.2.1 |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
190 |
because of this; this was fixed in 2.2.2. Use of COUNT_ALLOCS makes |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
191 |
all heap-allocated type objects immortal, except for those for which no |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
192 |
object of that type is ever allocated. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
193 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
194 |
Starting with Python 2.3, If Py_TRACE_REFS is also defined, COUNT_ALLOCS |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
195 |
arranges to ensure that the type object for each allocated object |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
196 |
appears in the doubly-linked list of all objects maintained by |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
197 |
Py_TRACE_REFS. |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
198 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
199 |
Special gimmicks: |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
200 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
201 |
sys.getcounts() |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
202 |
Return a list of 4-tuples, one entry for each type object for which |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
203 |
at least one object of that type was allocated. Each tuple is of |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
204 |
the form: |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
205 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
206 |
(tp_name, tp_allocs, tp_frees, tp_maxalloc) |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
207 |
|
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
208 |
Each distinct type object gets a distinct entry in this list, even |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
209 |
if two or more type objects have the same tp_name (in which case |
2fb8b9db1c86
Initial QEMU (symbian-qemu-0.9.1-12) import
martin.trojer@nokia.com
parents:
diff
changeset
|
210 |
there's no way to distinguish them by looking at this list). The |
2fb8b9db1c86
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211 |
list is ordered by time of first object allocation: the type object |
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for which the first allocation of an object of that type occurred |
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most recently is at the front of the list. |
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214 |
--------------------------------------------------------------------------- |
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215 |
LLTRACE introduced well before 1.0 |
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216 |
|
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217 |
Compile in support for Low Level TRACE-ing of the main interpreter loop. |
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218 |
|
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When this preprocessor symbol is defined, before PyEval_EvalFrame |
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(eval_frame in 2.3 and 2.2, eval_code2 before that) executes a frame's code |
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it checks the frame's global namespace for a variable "__lltrace__". If |
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such a variable is found, mounds of information about what the interpreter |
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is doing are sprayed to stdout, such as every opcode and opcode argument |
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and values pushed onto and popped off the value stack. |
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225 |
|
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Not useful very often, but very useful when needed. |
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227 |
|
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--------------------------------------------------------------------------- |
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CALL_PROFILE introduced for Python 2.3 |
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230 |
|
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Count the number of function calls executed. |
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232 |
|
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When this symbol is defined, the ceval mainloop and helper functions |
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count the number of function calls made. It keeps detailed statistics |
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about what kind of object was called and whether the call hit any of |
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the special fast paths in the code. |
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237 |
|
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--------------------------------------------------------------------------- |
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WITH_TSC introduced for Python 2.4 |
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240 |
|
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Super-lowlevel profiling of the interpreter. When enabled, the sys |
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module grows a new function: |
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243 |
|
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244 |
settscdump(bool) |
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If true, tell the Python interpreter to dump VM measurements to |
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stderr. If false, turn off dump. The measurements are based on the |
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processor's time-stamp counter. |
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248 |
|
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This build option requires a small amount of platform specific code. |
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250 |
Currently this code is present for linux/x86 and any PowerPC platform |
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251 |
that uses GCC (i.e. OS X and linux/ppc). |
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252 |
|
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On the PowerPC the rate at which the time base register is incremented |
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is not defined by the architecture specification, so you'll need to |
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255 |
find the manual for your specific processor. For the 750CX, 750CXe |
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256 |
and 750FX (all sold as the G3) we find: |
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257 |
|
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258 |
The time base counter is clocked at a frequency that is |
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259 |
one-fourth that of the bus clock. |
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260 |
|
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261 |
This build is enabled by the --with-tsc flag to configure. |