On 25 Nov, 13:11, Antoine Pitrou solip...@pitrou.net wrote:
When you say executing each kind of bytecode instruction, are you
talking about the overhead of bytecode dispatch and operand gathering, or
the total cost including doing the useful work?
Strip away any overhead (dispatch, operand
Le Tue, 24 Nov 2009 22:08:19 +, Benjamin Peterson a écrit :
Would it be worth in-lining the remaining part of PyObject_IsTrue in
ceval?
Inlining by hand is prone to error and maintainability problems.
Which is why we like to do it :-))
--
Le Tue, 24 Nov 2009 16:09:10 -0800, Paul Boddie a écrit :
I'm referring to what you're talking about at the end. The enhancements
in Python 3 presumably came about after discussion of threaded
interpreters, confirming that the evaluation loop in Python 2 was not
exactly optimal.
An optimal
#!/usr/local/bin/python
import timeit
def pythonic():
nonevar = None
zerovar = 0
for x in range(100):
if nonevar:
pass
if zerovar:
pass
def unpythonic():
nonevar = None
zerovar = 0
for x in range(100):
if nonevar
mk wrote:
#!/usr/local/bin/python
import timeit
def pythonic():
nonevar = None
zerovar = 0
for x in range(100):
if nonevar:
pass
if zerovar:
pass
def unpythonic():
nonevar = None
zerovar = 0
for x in range(100):
mk wrote in news:mailman.915.1259064240.2873.python-l...@python.org in
comp.lang.python:
def pythonic():
def unpythonic():
Decidedly counterintuitive: are there special optimizations for if
nonevar: type of statements in cpython implementation?
from dis import dis
dis(
On Tue, Nov 24, 2009 at 4:31 AM, Rob Williscroft r...@freenet.co.uk wrote:
mk wrote in news:mailman.915.1259064240.2873.python-l...@python.org in
comp.lang.python:
def pythonic():
def unpythonic():
Decidedly counterintuitive: are there special optimizations for if
nonevar: type of
MRAB wrote:
In what way is it counterintuitive? In 'pythonic' the conditions are
simpler, less work is being done, therefore it's faster.
But the pythonic condition is more general: nonevar or zerovar can be
'', 0, or None. So I thought it was more work for interpreter to compare
those,
mk wrote in news:mailman.923.1259070092.2873.python-l...@python.org in
comp.lang.python:
MRAB wrote:
In what way is it counterintuitive? In 'pythonic' the conditions are
simpler, less work is being done, therefore it's faster.
But the pythonic condition is more general: nonevar or zerovar
Hello,
Le Tue, 24 Nov 2009 14:41:19 +0100, mk a écrit :
As Rob pointed out (thanks):
11 31 LOAD_FAST0 (nonevar)
34 JUMP_IF_FALSE4 (to 41)
I'm no good at py compiler or implementation internals and so I have no
idea what bytecode
On 2009-11-24, Antoine Pitrou solip...@pitrou.net wrote:
It tries to evaluate the op of the stack (here nonevar) in a
boolean context (which theoretically involves calling
__nonzero__ on the type)
...or __bool__ in Py3K.
--
Neil Cerutti
--
Le Tue, 24 Nov 2009 15:11:29 +, Antoine Pitrou a écrit :
Hello,
Le Tue, 24 Nov 2009 14:41:19 +0100, mk a écrit :
As Rob pointed out (thanks):
11 31 LOAD_FAST0 (nonevar)
34 JUMP_IF_FALSE4 (to 41)
I'm no good at py compiler or
On 24 Nov, 16:11, Antoine Pitrou solip...@pitrou.net wrote:
[JUMP_IF_FALSE]
It tries to evaluate the op of the stack (here nonevar) in a boolean
context (which theoretically involves calling __nonzero__ on the type)
and then jumps if the result is False (rather than True).
[...]
As
Le Tue, 24 Nov 2009 08:58:40 -0800, Paul Boddie a écrit :
As you
point out, a lot of this RISC vs. CISC analysis (and inferences drawn
from Python bytecode analysis) is somewhat academic: the cost of the
JUMP_IF_FALSE instruction is likely to be minimal in the context of all
the activity
On Tue, 2009-11-24 at 18:25 +, Antoine Pitrou wrote:
Le Tue, 24 Nov 2009 08:58:40 -0800, Paul Boddie a écrit :
As you
point out, a lot of this RISC vs. CISC analysis (and inferences
drawn
from Python bytecode analysis) is somewhat academic: the cost of the
JUMP_IF_FALSE instruction
Tim Wintle tim.wintle at teamrubber.com writes:
Out of interest - has anyone else spotted that the call to
PyObject_IsTrue in the XXX_JUMP_IF_ blocks performs two unnecessary
pointer comparisons?
I doubt two pointer comparisons will make much of a difference.
Would it be worth in-lining
Chris Rebert wrote:
On Tue, Nov 24, 2009 at 4:31 AM, Rob Williscroft r...@freenet.co.uk wrote:
mk wrote in news:mailman.915.1259064240.2873.python-l...@python.org in
comp.lang.python:
def pythonic():
def unpythonic():
Decidedly counterintuitive: are there special optimizations for if
On 24 Nov, 19:25, Antoine Pitrou solip...@pitrou.net wrote:
Sorry, I have trouble parsing your sentence. Do you mean bytecode
interpretation overhead is minimal compared to the cost of actual useful
work, or the contrary?
(IMO both are wrong by the way)
I'm referring to what you're talking
18 matches
Mail list logo
