>> Metalone wrote:
>>> I just tried the seek test with Cython.
>>> Cython fseek() : 1.059 seconds. 30% slower than 'C'
>>> Python f.seek : 1.458 secondds. 80% slower than 'C'.
>>>
>>> It is amazing to me that Cython generates a 'C' file that is 1478
>>> lines.
>>
>> PythoidC ( http://pythoidc.goo
I almost wrote a long reply to all this.
In the end it boils down to being concerned about how much overhead
there is to calling a 'C' function.
I assumed that file.seek() simply delegated to fseek() and thus was
one way to test this overhead.
However, I now think that it must be doing more and may
Le Tue, 09 Mar 2010 15:56:47 -0800, Metalone a écrit :
> for i in xrange(100):
>f1.seek(0)
This is quite a stupid benchmark to write, since repeatedly seeking to 0
is a no-op. I haven't re-read the file object code recently, but chances
are that the Python file object has its own
Metalone, 11.03.2010 23:57:
I just tried the seek test with Cython.
Cython fseek() : 1.059 seconds. 30% slower than 'C'
Python f.seek : 1.458 secondds. 80% slower than 'C'.
It is amazing to me that Cython generates a 'C' file that is 1478
lines.
Well, it generated an optimised Python interfa
CHEN Guang, 12.03.2010 08:51:
Metalone wrote:
I just tried the seek test with Cython.
Cython fseek() : 1.059 seconds. 30% slower than 'C'
Python f.seek : 1.458 secondds. 80% slower than 'C'.
It is amazing to me that Cython generates a 'C' file that is 1478
lines.
PythoidC ( http://pythoidc.
Metalone wrote:
> I just tried the seek test with Cython.
> Cython fseek() : 1.059 seconds. 30% slower than 'C'
> Python f.seek : 1.458 secondds. 80% slower than 'C'.
>
> It is amazing to me that Cython generates a 'C' file that is 1478
> lines.
>
PythoidC ( http://pythoidc.googlecode.com )
Metalone wrote:
> I just tried the seek test with Cython.
> Cython fseek() : 1.059 seconds. 30% slower than 'C'
> Python f.seek : 1.458 secondds. 80% slower than 'C'.
>
> It is amazing to me that Cython generates a 'C' file that is 1478
> lines.
>
And what response are you seeking to your amaze
I just tried the seek test with Cython.
Cython fseek() : 1.059 seconds. 30% slower than 'C'
Python f.seek : 1.458 secondds. 80% slower than 'C'.
It is amazing to me that Cython generates a 'C' file that is 1478
lines.
#Cython code
import time
cdef int SEEK_SET = 0
cdef extern from "stdio.h"
I am assuming that Python delegates the f.seek call to the seek call
in the MS C runtime library msvcrt.dll.
Does anybody know a nice link to the Python source like was posted
above for the BSD 'C' library?
Ok, I ran some more tests.
C, seek: 0.812 seconds // test from original post
On Mar 10, 6:01 pm, Neil Hodgson
wrote:
> Metalone:
>
> > As it turns out each call is only
> > 646 nanoseconds slower than 'C'.
> > However, that is still 80% of the time to perform a file seek,
> > which I would think is a relatively slow operation compared to just
> > making a system call.
>
>
Metalone:
> As it turns out each call is only
> 646 nanoseconds slower than 'C'.
> However, that is still 80% of the time to perform a file seek,
> which I would think is a relatively slow operation compared to just
> making a system call.
A seek may not be doing much beyond setting a current
Thanks, Tim.
Good to know.
--
http://mail.python.org/mailman/listinfo/python-list
f1_seek = f1.seek did not change the performance at all.
As it turns out each call is only
646 nanoseconds slower than 'C'.
However, that is still 80% of the time to perform a file seek,
which I would think is a relatively slow operation compared to just
making a system call.
--
http://mail.python
Metalone wrote:
>
>static void main(int argc, char *argv[])
As a side note, do you realize that this definition is invalid, in two
ways? "main" cannot be declared "static". The whole reason we use the
special name "main" is so that the startup code in the C run-time can link
to it. If "main" i
This is a pretty tight loop:
for i in xrange(100):
f1.seek(0)
But there is still a lot going on, some of which you can lift out of
the loop. The easiest I can think of is the lookup of the 'seek'
attribute on the f1 object. Try this:
f1_seek = f1.seek
for i in xrange(100):
I ran a comparison that timed 1e6 file seeks.
The tests were run with Python 2.6.4 and Microsoft Visual C 6.0 on
Windows XP with an Intel 3GHz single processor with hyperthreading.
Results:
C: 0.812 seconds
Python: 1.458 seconds.
difference = 0.646 seconds.
If the file.seek is removed the
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