On 09/09/2013 08:43 AM, Mark Shannon wrote:
I would like time to investigate this further, but at the moment I think it
will either make attribute lookup poorly
defined or slow.
Of the top of my head, the problem as a I see it is basically this:
Currently, type.__getattribute__() is a fixed point in the lookup of attributes.
The proposal means that a fixed point is not reached until the cls parameter of
type.__getattribute__() is either object
or type,
otherwise type.__getattribute__() and type.__locallookup__ must bounce back and
forth.
This will slow down *every* attribute lookup for what is a fairly obscure use
case.
Looks like there's a patch we can try at http://bugs.python.org/issue18181.
Here are Ronald's last timings:
-------------------------------------------------------------------------------
PYBENCH 2.1
-------------------------------------------------------------------------------
* using CPython 3.4.0a0 (default, Jul 29 2013, 13:01:34) [GCC 4.4.7
20120313 (Red Hat 4.4.7-3)]
* disabled garbage collection
* system check interval set to maximum: 2147483647
* using timer: time.perf_counter
* timer: resolution=1e-09, implementation=clock_gettime(CLOCK_MONOTONIC)
-------------------------------------------------------------------------------
Benchmark: pep447.pybench
-------------------------------------------------------------------------------
Rounds: 10
Warp: 10
Timer: time.perf_counter
Machine Details:
Platform ID:
Linux-2.6.32-358.114.1.openstack.el6.x86_64-x86_64-with-centos-6.4-Final
Processor: x86_64
Python:
Implementation: CPython
Executable: /tmp/default-pep447/bin/python3
Version: 3.4.0a0
Compiler: GCC 4.4.7 20120313 (Red Hat 4.4.7-3)
Bits: 64bit
Build: Jul 29 2013 14:09:12 (#default)
Unicode: UCS4
-------------------------------------------------------------------------------
Comparing with: default.pybench
-------------------------------------------------------------------------------
Rounds: 10
Warp: 10
Timer: time.perf_counter
Machine Details:
Platform ID:
Linux-2.6.32-358.114.1.openstack.el6.x86_64-x86_64-with-centos-6.4-Final
Processor: x86_64
Python:
Implementation: CPython
Executable: /tmp/default/bin/python3
Version: 3.4.0a0
Compiler: GCC 4.4.7 20120313 (Red Hat 4.4.7-3)
Bits: 64bit
Build: Jul 29 2013 13:01:34 (#default)
Unicode: UCS4
Test minimum run-time average
run-time
this other diff this other
diff
-------------------------------------------------------------------------------
BuiltinFunctionCalls: 45ms 44ms +1.3% 45ms 44ms
+1.3%
BuiltinMethodLookup: 26ms 27ms -2.4% 27ms 27ms
-2.2%
CompareFloats: 33ms 34ms -0.7% 33ms 34ms
-1.1%
CompareFloatsIntegers: 66ms 67ms -0.9% 66ms 67ms
-0.8%
CompareIntegers: 51ms 50ms +0.9% 51ms 50ms
+0.8%
CompareInternedStrings: 34ms 33ms +0.4% 34ms 34ms
-0.4%
CompareLongs: 29ms 29ms -0.1% 29ms 29ms
-0.0%
CompareStrings: 43ms 44ms -1.8% 44ms 44ms
-1.8%
ComplexPythonFunctionCalls: 44ms 42ms +3.9% 44ms 42ms
+4.1%
ConcatStrings: 33ms 33ms -0.4% 33ms 33ms
-1.0%
CreateInstances: 47ms 48ms -2.9% 47ms 49ms
-3.4%
CreateNewInstances: 35ms 36ms -2.5% 36ms 36ms
-2.5%
CreateStringsWithConcat: 69ms 70ms -0.7% 69ms 70ms
-0.9%
DictCreation: 52ms 50ms +3.1% 52ms 50ms
+3.0%
DictWithFloatKeys: 40ms 44ms -10.1% 43ms 45ms
-5.8%
DictWithIntegerKeys: 32ms 36ms -11.2% 35ms 37ms
-4.6%
DictWithStringKeys: 29ms 34ms -15.7% 35ms 40ms
-11.0%
ForLoops: 30ms 29ms +2.2% 30ms 29ms
+2.2%
IfThenElse: 38ms 41ms -6.7% 38ms 41ms
-6.9%
ListSlicing: 36ms 36ms -0.7% 36ms 37ms
-1.3%
NestedForLoops: 43ms 45ms -3.1% 43ms 45ms
-3.2%
NestedListComprehensions: 39ms 40ms -1.7% 39ms 40ms
-2.1%
NormalClassAttribute: 86ms 82ms +5.1% 86ms 82ms
+5.0%
NormalInstanceAttribute: 42ms 42ms +0.3% 42ms 42ms
+0.0%
PythonFunctionCalls: 39ms 38ms +3.5% 39ms 38ms
+2.8%
PythonMethodCalls: 51ms 49ms +3.0% 51ms 50ms
+2.8%
Recursion: 67ms 68ms -1.4% 67ms 68ms
-1.4%
SecondImport: 41ms 36ms +12.5% 41ms 36ms
+12.6%
SecondPackageImport: 45ms 40ms +13.1% 45ms 40ms
+13.2%
SecondSubmoduleImport: 92ms 95ms -2.4% 95ms 98ms
-3.6%
SimpleComplexArithmetic: 28ms 28ms -0.1% 28ms 28ms
-0.2%
SimpleDictManipulation: 57ms 57ms -1.0% 57ms 58ms
-1.0%
SimpleFloatArithmetic: 29ms 28ms +4.7% 29ms 28ms
+4.9%
SimpleIntFloatArithmetic: 37ms 41ms -8.5% 37ms 41ms
-8.7%
SimpleIntegerArithmetic: 37ms 41ms -9.4% 37ms 42ms
-10.2%
SimpleListComprehensions: 33ms 33ms -1.9% 33ms 34ms
-2.9%
SimpleListManipulation: 28ms 30ms -4.3% 29ms 30ms
-4.1%
SimpleLongArithmetic: 26ms 26ms +0.5% 26ms 26ms
+0.5%
SmallLists: 40ms 40ms +0.1% 40ms 40ms
+0.1%
SmallTuples: 46ms 47ms -2.4% 46ms 48ms
-3.0%
SpecialClassAttribute: 126ms 120ms +4.7% 126ms 121ms
+4.4%
SpecialInstanceAttribute: 42ms 42ms +0.6% 42ms 42ms
+0.8%
StringMappings: 94ms 91ms +3.9% 94ms 91ms
+3.8%
StringPredicates: 48ms 49ms -1.7% 48ms 49ms
-2.1%
StringSlicing: 45ms 45ms +1.4% 46ms 45ms
+1.5%
TryExcept: 23ms 22ms +4.9% 23ms 22ms
+4.8%
TryFinally: 32ms 32ms -0.1% 32ms 32ms
+0.1%
TryRaiseExcept: 17ms 17ms +0.9% 17ms 17ms
+0.5%
TupleSlicing: 49ms 48ms +1.1% 49ms 49ms
+1.0%
WithFinally: 48ms 47ms +2.3% 48ms 47ms
+2.4%
WithRaiseExcept: 45ms 44ms +0.8% 45ms 45ms
+0.5%
-------------------------------------------------------------------------------
Totals: 2284ms 2287ms -0.1% 2306ms 2308ms
-0.1%
(this=pep447.pybench, other=default.pybench)
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