how fast is Python?

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dan

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Aug 20, 2003, 4:08:20 PM8/20/03
to
It would be an understatement to say I love this language. What used
to take me all day now takes 3 hours, and I can spend the rest of the
time on my bike thinking about the problems from a high level instead
of wrestling with arcane compiler problems, etc.

Back in the day, when looking at an interpreted language (or even
compiled ones) the first thing I would ask is, "how fast is it?"
These days, with 1ghz processor machines selling for < $500, it seldom
comes up as an issue. And of course in Py's case you can always
'extend and embed' your core routines for fun & profit.

However, there are definitely cases where a lot of code would need to
be optimized, and so I ask the question: How fast is Python, compared
to say a typical optimizing C/C++ compiler?

I realize this is a more complex question than one might think. There
are various types of code constructs that might end up with different
efficiency issues. I guess what I'm asking is, in a general sense,
how fast is it now for typical code sequences, and -- importantly --
what could be done to optimize the interpreter? Are any parts written
in assembly? Could things like hash tables be optimized with parallel
units such as MMX? Etc.

Please advise.

Irmen de Jong

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Aug 20, 2003, 5:19:14 PM8/20/03
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Python is fast enough for me, especially 2.3.

Profile & code slow parts as C extensions.
Include your own assembly there if so desired.

Investigate Psyco. There was one example on this
newsgroup that showed that Python+psyco actually
outperformed the same program in compiled C.

--Irmen

Andrew Dalke

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Aug 20, 2003, 6:00:19 PM8/20/03
to
dan:

> However, there are definitely cases where a lot of code would need to
> be optimized, and so I ask the question: How fast is Python, compared
> to say a typical optimizing C/C++ compiler?

Highly dependent on context. I use factor of 10-20 as a ballpark,
with factor of 100 for some things like low-level string processing.
Eg, I've got a pure Python regexp engine which clocks at about x80
slower than sre.

> what could be done to optimize the interpreter? Are any parts written
> in assembly? Could things like hash tables be optimized with parallel
> units such as MMX? Etc.

Spend a few tens of millions on developing just-in-time compilers
and program analysis. That worked for Java.

Nothing is written in assembly, except that C can be considered
a portable assembly language. Otherwise ports to different platforms
would be a lot more difficult.

I would hope that the C compiler could optimize the C code
sufficiently well for the hardware, rather than tweaking the
code by hand. (Though I know of at least one person who sent
in a patch to gcc to optimize poorly written in-house code.
Rather circuitous way to fix things, but it worked.)

Andrew
da...@dalkescientific.com


Michael Peuser

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Aug 21, 2003, 12:40:04 AM8/21/03
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"Irmen de Jong" <irmen@-NOSPAM-REMOVETHIS-xs4all.nl> schrieb im Newsbeitrag
news:3f43e5cf$0$49115$e4fe...@news.xs4all.nl...

This are my advice as well. Especially use the profiler and change your
high level algorithms. You will find a lot with hidden quadratic behavaviour
which slow down your program when it comes to high volume.

Psyco will generally speed up 2. This is fine (I use it!) but not a break
through. There may be cases where it performs better.

A bottleneck can be Tkinter. Use something different then (Qt, wx)..

Kindly
Michael P


Raymond Hettinger

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Aug 21, 2003, 1:15:56 AM8/21/03
to
"dan"

> However, there are definitely cases where a lot of code would need to
> be optimized, and so I ask the question: How fast is Python, compared
> to say a typical optimizing C/C++ compiler?

The extension modules run at optimized C speed because they *are*
optimized C.

For pure python applications, Psyco can provide just-in-time native
compilation.

Tim once said that anything written using Python's dictionaries are
zillions of times faster that anything else. There is a grain of truth
in that because Python makes it so easy to create efficient data
structures that their performance can surpass less data
structures written in assembly or C.

All that being said, Python is designed for those who value
programmer time more than they value clock cycles.


Raymond Hettinger


Alex Martelli

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Aug 21, 2003, 2:19:54 AM8/21/03
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Irmen de Jong wrote:

I think (but will gladly stand corrected if I'm wrong!) that
this is a misinterpretation of some code I posted -- the
C code (crazily) used pow(x,2.0), the Python one (sanely)
x*x -- within a complicated calculation of erf, and that
one malapropism in the C code was what let psyco make
faster code than C did. With C fixed to use x*x -- as any
performance-aware programmer will always code -- the
two ran neck to neck, no advantage to either side.


Alex

Irmen de Jong

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Aug 21, 2003, 4:14:00 AM8/21/03
to
Alex Martelli wrote:
> Irmen de Jong wrote:

>>Investigate Psyco. There was one example on this
>>newsgroup that showed that Python+psyco actually
>>outperformed the same program in compiled C.
>
>
> I think (but will gladly stand corrected if I'm wrong!) that
> this is a misinterpretation of some code I posted -- the
> C code (crazily) used pow(x,2.0), the Python one (sanely)
> x*x -- within a complicated calculation of erf, and that
> one malapropism in the C code was what let psyco make
> faster code than C did. With C fixed to use x*x -- as any
> performance-aware programmer will always code -- the
> two ran neck to neck, no advantage to either side.

Whoops, I missed that :) Thanks for the clarification.

Nevertheless, a Psyco-optimized piece of Python code
that runs as fast as compiled C is still very impressive
to me. I know that JIT compiler technology theoretically
could produce better optimized code than a static optimizing
compiler, but am happy already if it reaches equal level :-)

--Irmen de Jong

Alex Martelli

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Aug 21, 2003, 4:50:30 AM8/21/03
to
Irmen de Jong wrote:
...

> Nevertheless, a Psyco-optimized piece of Python code
> that runs as fast as compiled C is still very impressive
> to me. I know that JIT compiler technology theoretically
> could produce better optimized code than a static optimizing
> compiler, but am happy already if it reaches equal level :-)

If anybody does have an actual example (idealy toy-sized:-)
where psyco's JIT does make repeatably faster code than a
C compiler (well-used, e.g. -O3 for gcc, NOT just -O...!-)
I'd be overjoyed to see it, by the way.


Alex

David McNab

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Aug 21, 2003, 5:07:20 AM8/21/03
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On Thu, 21 Aug 2003 06:40:04 +0200, Michael Peuser paused, took a deep
breath, then came out with:

> A bottleneck can be Tkinter. Use something different then (Qt, wx)..

Wow!

I've found wx to be way slower than Tkinter.

On a P133 running Win98, a McMillan-compiled prog using wx took twice as
long to start up as a similar prog implemented in Tkinter.


Mark Carter

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Aug 21, 2003, 8:13:36 AM8/21/03
to
> > However, there are definitely cases where a lot of code would need to
> > be optimized, and so I ask the question: How fast is Python, compared
> > to say a typical optimizing C/C++ compiler?

I did a benchmark some time ago (nothing optimised):

PURPOSE:
The purpose of this technical report is to gauge the relative speed of
the languages: VB, VBA, Python 2.2, C++, and Fortran.


SUMMARY RESULTS:
It was discovered that uncompiled VB code in VB 6.0 ran at the same
speed as VBA code in Excel. It was half the speed of compiled VB code,
5 times the speed of Python, and 1/20th the speed of C++/Fortran.

METHOD:

The following algorithm was implemented in each of the target
languages:

X = 0.5
For I = 1 to 108
X = 1 – X* X
Next

Timings were made for the execution. The following results were
obtained:

Language Timing (seconds)
VB – uncompiled 74
VB – compiled 37
VBA – Excel 75
Python 401
C++ - debug version 4
C++ - release version 3
Fortran 3


The timings for Fortran are approximate. The execution time had to be
timed with a stopwatch because timing functions could not be
discovered.

Neil Padgen

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Aug 21, 2003, 10:22:01 AM8/21/03
to
On Wednesday 20 August 2003 21:19, Irmen de Jong wrote:
> Investigate Psyco.

On the strength of this thread, I investigated Psyco. Results of a
very quick investigation with the following program:

-----------------------------------------
def calcPi(iterations):
pi4 = 1.0
for i in xrange(1, iterations):
denominator = (4*i)-1
pi4 = pi4 - 1.0/denominator + 1.0/(denominator+2)
return pi4 * 4.0

def timethis(func, funcName):
import sys
try:
i = int(sys.argv[1])
except:
i = 1000000
import time
start = time.time()
pi = func(i)
end = time.time()
print "%s calculated pi as %s in %s seconds" % (funcName, pi, end
- start)

def main():
timethis(calcPi, 'calcPi')
timethis(speedyPi, 'speedyPi')

import psyco
speedyPi = psyco.proxy(calcPi)

if __name__ == '__main__':
main()
-----------------------------------------

produced the following results on a 1.7GHz P4 running FreeBSD 4.8:

> python2.2 pi.py
calcPi calculated pi as 3.14159315359 in 3.87623202801 seconds
speedyPi calculated pi as 3.14159315359 in 0.790405035019 seconds

-- Neil

Travis Whitton

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Aug 21, 2003, 10:42:26 AM8/21/03
to
If you haven't seen this, you should check it out. It compares a variety
of languages to each other, and it's probably the best site on the
internet for side-by-side language comparisons:

http://www.bagley.org/~doug/shootout/

-Travis

Peter Hansen

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Aug 21, 2003, 11:06:19 AM8/21/03
to
dan wrote:
>
> However, there are definitely cases where a lot of code would need to
> be optimized, and so I ask the question: How fast is Python, compared
> to say a typical optimizing C/C++ compiler?

C is roughly 10 to 100 times faster than Python, though of course it's
easy to find cases outside of this range, on either side.

I use 30 as a general overall rule of thumb, in the exceptionally
few cases where it seems relevant how much faster C would be.

And in those very few cases, so far, I have consistently concluded
I'm happy enough with the speed of Python given that the speed of
*development* in Python is easily 5 to 10 times faster than the
speed of development in C. (And again, it's easy to find cases
outside of this range, on either side...)

-Peter

Mark Carter

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Aug 21, 2003, 12:11:51 PM8/21/03
to
carter...@ukmail.com (Mark Carter) wrote in message

> It was discovered that uncompiled VB code in VB 6.0 ran at the same
> speed as VBA code in Excel. It was half the speed of compiled VB code,
> 5 times the speed of Python, and 1/20th the speed of C++/Fortran.

Although, as the saying goes, there's no such thing as a slow language
- only slow implementations.

Alex Martelli

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Aug 21, 2003, 12:25:51 PM8/21/03
to
Mark Carter wrote:
...

> The following algorithm was implemented in each of the target
> languages:
>
> X = 0.5
> For I = 1 to 108
> X = 1 X* X
> Next
>
> Timings were made for the execution. The following results were
> obtained:
>
> Language Timing (seconds)
> VB uncompiled 74
> VB compiled 37
> VBA Excel 75
> Python 401
> C++ - debug version 4
> C++ - release version 3
> Fortran 3

Interesting. One wonders what and where you measured, e.g:

[alex@lancelot gmpy]$ cat a.cpp
int main()
{
double X = 0.5;
for(int i = 0; i < 108; i++)
X = 1 + X * X;
return 0;
}

[alex@lancelot gmpy]$ g++ -O3 a.cpp
[alex@lancelot gmpy]$ time ./a.out
0.01user 0.00system 0:00.00elapsed 333%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (186major+21minor)pagefaults 0swaps

i.e., it's just too fast to measure. Not much better w/Python...:

[alex@lancelot gmpy]$ cat a.py

def main():
X = 0.5
for i in xrange(108):
X = 1 + X*X

main()
[alex@lancelot gmpy]$ time python -O a.py
0.03user 0.01system 0:00.15elapsed 26%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (452major+260minor)pagefaults 0swaps

i.e., for all we can tell, the ratio COULD be 100:1 -- or just about
anything else! Perhaps more details are warranted...


Alex

ach...@easystreet.com

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Aug 21, 2003, 12:30:05 PM8/21/03
to
dan wrote:
>
> I realize this is a more complex question than one might think. >
> Please advise.

Consider the percentage of software projects for which the total
number of hours of developer time over the life of the project
exceeds the total number of hours of CPU run time during productive
use of the software produced. This percentage is abysmally high.
Python works on improving it on both ends, by both reducing the
developer time and increasing the number of hours of productive
use. What more could you want?


Al

Andrew Dalke

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Aug 21, 2003, 1:19:06 PM8/21/03
to
Travis Whitton
> [the shootout] is probably the best site on the

> internet for side-by-side language comparisons:

Though there's also pleac.sf.net which isn't for timings
but does show how the different languages would be
used to do the same thing.

And I see my Python contribution still leads the
pack in % done.

Andrew
da...@dalkescientific.com


Michael Peuser

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Aug 21, 2003, 2:56:14 PM8/21/03
to
"David McNab" <postm...@127.0.0.1> schrieb im Newsbeitrag
news:pan.2003.08.21....@127.0.0.1...

Of course! The wx DLL is mor ethan 6 MB whilest Tcl/Tk still keeps around 1.
I am not talking about start up. When you have ever used a Canvas with a
600x800 Image oder with a thousend items or a TIX HList with a dozend
diffently styled columns you might know WHAT I am talking about.

Even with less filled widgets, most of what you perceive as "lazy" with e.g.
games is generally not the Python but the Tcl interpreter. Pygame shows that
you can dio fast visualisation with Python.

Kindly
Michael P


Michael Peuser

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Aug 21, 2003, 3:02:17 PM8/21/03
to

"Neil Padgen" <neil....@mon.bbc.co.uk> schrieb im Newsbeitrag
news:bi2ki9$pai$1...@nntp0.reith.bbc.co.uk...

> On Wednesday 20 August 2003 21:19, Irmen de Jong wrote:
> > Investigate Psyco.
>

[...]


>
> produced the following results on a 1.7GHz P4 running FreeBSD 4.8:
>
> > python2.2 pi.py
> calcPi calculated pi as 3.14159315359 in 3.87623202801 seconds
> speedyPi calculated pi as 3.14159315359 in 0.790405035019 seconds
>
> -- Neil

This is certainly correct. My experiance with more general programs running
for a few minutes shows that you can expect a speed-up of two. This is still
impressiv when you have your results in 5 instead of 10 minutes..

Kindly
Michael P


Jimmy Retzlaff

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Aug 21, 2003, 7:30:50 AM8/21/03
to

In a way this comes back to practicality vs. purity. In a synthetic
benchmark where one function is called repeatedly with homogeneous data,
it's hard to imagine that a JIT compiler could ever outperform a good
optimizing C compiler. But that's the pure side of a performance
analysis. The practical side is how that function performs in a real
application where a JIT for a dynamically typed language has much more
information to work with than a C compiler does.

For example, a C compiler might only know that you declared a parameter
as a double and so it can only optimize for that. If you happen to call
the function more often than not with an int (that gets promoted to a
double on the way in) then the compiler generated code may waste a good
deal of time doing floating point arithmetic rather than integer
arithmetic. Now the programmer might take the time to profile their C
program and hopefully notice that time is being wasted doing floating
point arithmetic and then create an int version of their function, but
often practical constraints will get in the way of this happening.

This brings back memories of the old arguments about optimizing C
compilers being able to generate faster code that hand written assembly.
Of course an expert at assembly could write a faster program given
enough time, but most people didn't have the time or expertise to write
assembly code that could perform as well as optimized C once the
compilers attained a certain level of sophistication. In many practical
situations C is faster than assembly. PyPy is exciting because it
presents hope of providing the JIT with enough extra information and
flexibility that it may be able to make practical Python code outperform
practical C code in many cases.

The example above involving double/int was not just an example. It
happened in an application of mine a while back. I replaced a function
in a C extension with a Psyco-compiled Python version of the same
function and the performance of the part of my application that used the
function doubled. I posted a couple of notes about it. The first is
about a test in isolation (the pure test) and C was faster:

http://tinyurl.com/kpgd (includes Python code and links to C code)

The second note came later after I decided the slightly slower
Python/Psyco version was fast enough to eliminate the headaches of
maintaining the C extension. After replacing the C code I was startled
by a performance improvement in my application. This is the about the
practical test:

http://tinyurl.com/kpg6

And finally a bit of a caveat:

http://tinyurl.com/kpid

Jimmy


dan

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Aug 21, 2003, 9:27:52 PM8/21/03
to
Peter Hansen <pe...@engcorp.com> wrote in message news:<3F44DFEB...@engcorp.com>...
...

> And in those very few cases, so far, I have consistently concluded
> I'm happy enough with the speed of Python given that the speed of
> *development* in Python is easily 5 to 10 times faster than the
> speed of development in C. (And again, it's easy to find cases
> outside of this range, on either side...)
>
I pretty much agree. The point of my question was not to knock Python
-- I'm simply curious how fast, _in_principle_, a language like Python
could be made to run.

I've looked at Psyco and Pyrex, I think both are interesting projects
but I doubt anything in the Py world has had nearly the kind of
man-hours devoted to optimization that Java, C++, and probably C# have
had.

Jeff Epler

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Aug 21, 2003, 2:58:53 PM8/21/03
to
I don't know what Mark Carter wanted to measure either, but I'd like to
mention that when I compile "a.cpp" on my system with the flags Alex
used, the generated code doesn't even include any floating-point
arithmetic. The compiler was able to deduce that X was dead after the
loop, and that its computation had no side-effects. I'm a little
surprised that the compiler didn't completely remove the loop, but it's
still there. "i" isn't there either, instead there's a counter that
begins at 107, decrements and terminates the loop when it reaches -1.
And if I use the directive to unroll loops, the logic is the same except
that the counter decreases by 18 each time instead of 1.

... and anyway, this modified code (which does actually compute X when
compiled on my system) aborts with a floating point overflow error.
As far as I can tell, your program would be computing a value on the
order of 10^(3x10^31)...

Ah, the joy of writing the proverbial good benchmark.

Jeff

#include <fpu_control.h>
fpu_control_t __fpu_control = _FPU_IEEE &~ _FPU_MASK_OM;

double Y;

int main()
{
double X = 0.5;
for(int i = 0; i < 108; i++)
X = 1 + X * X;

Y = X;
return 0;
}


Andrew Dalke

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Aug 22, 2003, 1:23:04 AM8/22/03
to
Jeff Epler:

> As far as I can tell, your program would be computing a value on the
> order of 10^(3x10^31)...

> for(int i = 0; i < 108; i++)


> X = 1 + X * X;

He had 1-X*X. Since X starts at 0.5, this will never go leave
the range 0 to 1.

Andrew
da...@dalkescientific.com


Peter Hansen

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Aug 22, 2003, 11:37:02 AM8/22/03
to

Oh, I completely misinterpreted the question then. I thought you wanted
practical information.

_In principle_, (which I'll interpret as "in theory"), Python can be made
to run even faster than C or C++.

In practice, nobody has been able to prove or disprove that theory yet...

;-)

-Peter

Christos TZOTZIOY

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Aug 22, 2003, 8:38:43 PM8/22/03
to
On 20 Aug 2003 13:08:20 -0700, rumours say that danb...@yahoo.com
(dan) might have written:

>How fast is Python, compared
>to say a typical optimizing C/C++ compiler?

The most important time for me is the time *I* invest in a program,
since when it's run-time, I can always do other stuff while some slave
computer follows my orders. So, I'll reply only about development time
and I'll quote the Smiths: "How Soon Is Now?" :)
--
TZOTZIOY, I speak England very best,
Microsoft Security Alert: the Matrix began as open source.

Michele Simionato

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Aug 23, 2003, 7:18:12 AM8/23/03
to
Alex Martelli <al...@aleax.it> wrote in message news:<qJ%0b.116361$cl3.3...@news2.tin.it>...

Actually, as I posted in the C sharp thread of few weeks ago, on my
machine psyco+psyco was FASTER than C. The numbers quoted are for C
with
option -o, but even for -o3 psyco was still faster and, notice, with
pow(x,2) replacedby x*x in C too. I would be happy if somebody can
reproduce that. Here is the link:

http://groups.google.it/groups?hl=it&lr=&ie=UTF-8&threadm=2259b0e2.0308041106.7ac111cc%40posting.google.com&rnum=1&prev=/groups%3Fhl%3Dit%26lr%3D%26ie%3DISO-8859-1%26q%3Dsimionato%2Bspeed%2Bgroup%253Acomp.lang.python.*%2Bgroup%253Acomp.lang.python.*%26meta%3Dgroup%253Dcomp.lang.python.*

Michele Simionato, Ph. D.
MicheleS...@libero.it
http://www.phyast.pitt.edu/~micheles
--- Currently looking for a job ---

Cameron Laird

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Aug 24, 2003, 11:09:28 AM8/24/03
to
In article <3F44DFEB...@engcorp.com>,
.
.
.
I just think Peter's wise counsel bears repeating.

Andrew gave the same quantities, incidentally. Myself,
I use ten "as a general over-all rule of thumb", and
expect generally to be in the three-to-thirty range. I
know other programmers whose Python work consistently
runs about one-one-hundredth as fast as the C equivalent.
As near as I can tell, that reflects on the kinds of
programming we do (how numeric, and so on), rather than
the quality of our coding.
--

Cameron Laird <Cam...@Lairds.com>
Business: http://www.Phaseit.net
Personal: http://phaseit.net/claird/home.html

Steven Taschuk

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Aug 27, 2003, 5:08:16 PM8/27/03
to
Quoth Andrew Dalke:
> [...] (Though I know of at least one person who sent

> in a patch to gcc to optimize poorly written in-house code.
> Rather circuitous way to fix things, but it worked.)

A bit off-topic perhaps, but I'd be interested in the details of
this anecdote.

--
Steven Taschuk o- @
stas...@telusplanet.net 7O )
" (

Andrew Dalke

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Aug 27, 2003, 7:00:35 PM8/27/03
to
Steven Taschuk:

> A bit off-topic perhaps, but I'd be interested in the details of
> [your] anecdote.

Okay. I know someone who really likes optimized programming.
The kind of person who will develop an in-memory compiler
to generate specialized assembly for the exact parameters used,
thus squeezing out a few extra cycles. He works in a C++ company.
They used an idiom, the details of what I don't know. Most
people wouldn't use that idiom because it didn't translate well
to assembly, but the compiler in theory could figure it out. He
submitted a patch to do that optimization. It was originally
rejected because they couldn't see that anyone would write
code that way. He dug around in gcc itself to find some place
which used that code, to show that it is used. It was accepted.

Moral: it's easier to change the technical details (gcc) than
the social ones (getting people to use a better idiom).

That's about all I know of the story.

Andrew
da...@dalkescientific.com


Graham Fawcett

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Aug 28, 2003, 10:18:11 AM8/28/03
to
cla...@lairds.com (Cameron Laird) wrote in message news:<vkhl98p...@corp.supernews.com>...

> In article <3F44DFEB...@engcorp.com>,
> Peter Hansen <pe...@engcorp.com> wrote:
> >dan wrote:
> >>
> >> However, there are definitely cases where a lot of code would need to
> >> be optimized, and so I ask the question: How fast is Python, compared
> >> to say a typical optimizing C/C++ compiler?
> >
> >C is roughly 10 to 100 times faster than Python, though of course it's
> >easy to find cases outside of this range, on either side.
> >
> >I use 30 as a general overall rule of thumb, in the exceptionally
> >few cases where it seems relevant how much faster C would be.
> >
> >And in those very few cases, so far, I have consistently concluded
> >I'm happy enough with the speed of Python given that the speed of
> >*development* in Python is easily 5 to 10 times faster than the
> >speed of development in C. (And again, it's easy to find cases
> >outside of this range, on either side...)
> .
> .
> I just think Peter's wise counsel bears repeating.


My comment is completely off-topic, but I enjoyed a lyrical moment
when I mis-read Cameron's statement, and found myself imagining what
"Peter's wise counsel bears" looked like. I am envious of Peter,
having never made any magical forest-friends myself.

If we each had at least /one/ wise counsel bear, then c.l.py would
certainly reap the benefits of our enhanced posts!

Yours,

-- Graham

Steve Horsley

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Aug 28, 2003, 3:40:59 PM8/28/03
to
On Wed, 20 Aug 2003 22:00:19 +0000, Andrew Dalke wrote:


> Spend a few tens of millions on developing just-in-time compilers
> and program analysis. That worked for Java.

Have you heard of Jython - python language running on a java VM? It's kind
of double interpreted - the python source is converted to JVM bytecode,
and then the JVM runs it however that JVM runs bytecode. I guess it should
be many times faster than python because of the JVM performance, and
wopuld be interested to hear any comparisons.

Steve

Lawrence Oluyede

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Aug 28, 2003, 3:51:15 PM8/28/03
to
"Steve Horsley" <steve.h...@virgin.NO_SPAM.net> writes:

> Have you heard of Jython - python language running on a java VM? It's kind
> of double interpreted - the python source is converted to JVM bytecode,
> and then the JVM runs it however that JVM runs bytecode. I guess it should
> be many times faster than python because of the JVM performance, and
> wopuld be interested to hear any comparisons.

Jython faster than Python? We did little test and it doesn't seem, look:
http://tinyurl.com/liix

--
Lawrence "Rhymes" Oluyede
http://loluyede.blogspot.com
rhy...@NOSPAMmyself.com

Robin Becker

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Aug 29, 2003, 5:06:46 AM8/29/03
to
In article <pan.2003.08.28....@virgin.NO_SPAM.net>, Steve
Horsley <steve.h...@virgin.NO_SPAM.net> writes
experience with ReportLab suggests jython can be fairly slow compared to
CPython although it does have advantages.
--
Robin Becker

Andrew MacIntyre

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Aug 29, 2003, 5:50:21 AM8/29/03
to
On Fri, 29 Aug 2003, Robin Becker wrote:

> experience with ReportLab suggests jython can be fairly slow compared to
> CPython although it does have advantages.

The advantages being?

Regards,
Andrew.

--
Andrew I MacIntyre "These thoughts are mine alone..."
E-mail: and...@bullseye.apana.org.au (pref) | Snail: PO Box 370
and...@pcug.org.au (alt) | Belconnen ACT 2616
Web: http://www.andymac.org/ | Australia

Alan Kennedy

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Aug 29, 2003, 10:31:17 AM8/29/03
to
[Steve Horsley]

>> Have you heard of Jython - python language running on a java VM?
>> It's kind of double interpreted - the python source is converted
>> to JVM bytecode, and then the JVM runs it however that JVM runs
>> bytecode. I guess it should be many times faster than python
>> because of the JVM performance, and wopuld be interested to hear
>> any comparisons.

[Lawrence Oluyede]


> Jython faster than Python? We did little test and it doesn't seem, look:
> http://tinyurl.com/liix

Please bear in mind that the test code included the start up time for
interpreter. For jython, this is a high cost, because starting a JVM
often takes up to 10 seconds or more.

It would probably be fairer to run timings after the VM has already
been through the startup phase. I think that is a more valid
reflection of real-world scenarios where a VM gets started once and
left running for a long time.

regards,

--
alan kennedy
-----------------------------------------------------
check http headers here: http://xhaus.com/headers
email alan: http://xhaus.com/mailto/alan

Lawrence Oluyede

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Aug 29, 2003, 10:28:30 AM8/29/03
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Andrew MacIntyre <and...@bullseye.apana.org.au> writes:

> The advantages being?

I think gain access to Java stuff is an advantage in some situations,
isn't it?

Steve Lamb

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Aug 29, 2003, 11:25:27 AM8/29/03
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On 2003-08-20, dan <danb...@yahoo.com> wrote:
> However, there are definitely cases where a lot of code would need to
> be optimized, and so I ask the question: How fast is Python, compared
> to say a typical optimizing C/C++ compiler?

Recently on the debian-user list someone asked why C was as popular
as it was today with so many other languages around. Many people cited
that C runs faster. A bunch of Python people (myself included) pointed
out we could develop faster. Finally someone else asked why a large
program (in this case Evolution) couldn't be written in Python since it
isn't processor intensive. My answer hit it in one: "It wouldn't idle
as fast?"

Except for some rare instances in most cases any program waiting on
user input is going to be sitting idle almost the entire time that it is
running. Given that is there anyone who really cares how fast it idles?
As others have pointed out for the few cases where the program isn't
idling and the user might have something he's waiting on then clearly
stepping down to C and wrapping that in Python will help.

--
Steve C. Lamb | I'm your priest, I'm your shrink, I'm your
PGP Key: 8B6E99C5 | main connection to the switchboard of souls.
-------------------------------+---------------------------------------------

Lawrence Oluyede

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Aug 29, 2003, 11:14:00 AM8/29/03
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Alan Kennedy <ala...@hotmail.com> writes:

> Please bear in mind that the test code included the start up time for
> interpreter. For jython, this is a high cost, because starting a JVM
> often takes up to 10 seconds or more.

Yeah, you right. But here comes a question: why do you think that Jython
(and JVM) are faster than Python (and its VM)? In my own little tests is
Jython is always slower and GUI (with Swing) is not responsive as GTK for
example. I think Jython is an amazing and awesome "tool" for Python and
Java developers but I'm not so sure that is also faster than CPython.

Bye!

Robin Becker

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Aug 29, 2003, 11:47:11 AM8/29/03
to
In article <mailman.106216318...@python.org>, Andrew
MacIntyre <and...@bullseye.apana.org.au> writes

>On Fri, 29 Aug 2003, Robin Becker wrote:
>
>> experience with ReportLab suggests jython can be fairly slow compared to
>> CPython although it does have advantages.
>
>The advantages being?
>
>Regards,
>Andrew.
well I guess you can package it up into a single jar file and then ship
it to those big blue iron jvm environments ie it's another market.
--
Robin Becker

Irmen de Jong

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Aug 29, 2003, 12:15:17 PM8/29/03
to
Alan Kennedy wrote:
> Please bear in mind that the test code included the start up time for
> interpreter. For jython, this is a high cost, because starting a JVM
> often takes up to 10 seconds or more.

10?! On my machine, starting one of the swing demos from the 1.4.2
JDK takes anywhere between zero and two seconds.

While (C)Python is quicker than that, it can only be quicker by
two seconds, which can be ignored IMHO.

Mabe you meannot the startup time, but the time it takes
when the (server)HotSpot JIT reaches full speed. That sometimes
takes a while because it incrementally compiles the bytecodes.

--Irmen

Juha Autero

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Aug 30, 2003, 6:38:12 AM8/30/03
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graham_...@hotmail.com (Graham Fawcett) writes:

> If we each had at least /one/ wise counsel bear, then c.l.py would
> certainly reap the benefits of our enhanced posts!

That reminds me of a story I probably read from The Practice of
Programming by Brian W. Kernighan and Rob Pike. In some university
(I've forgotten the name) students doing programming exercises had to
explain their problem to a teddy bear before they could talk to course
staff. This was because often just explaining the problem helped you
to understand the problem and then you could fix it.

--
Juha Autero
http://www.iki.fi/jautero/
Eschew obscurity!


Peter Hansen

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Sep 2, 2003, 12:53:17 PM9/2/03
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Marc Wilson wrote:
>
> In comp.lang.python, Juha Autero <Juha....@iki.fi> (Juha Autero) wrote
> in <mailman.1062240014...@python.org>::
> The term I coined for this is "echo debugging". :)

I once spent about two hours in a debugging session with a friend.
We were away from the computer, discussing the problem, with a
whiteboard, diagrams, lots of talking.... after we found the
solution I said something about wow, that's great, we solved it.

My friend said, "Peter... _I_ didn't even say anything!". :-)

-Peter

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