On Nov 20, 2007 10:31 AM, koara <[EMAIL PROTECTED]> wrote: > Hello all, > > i am using the mmap module (python2.4) to access contents of a file. > > My question regards the relative performance of mmap.seek() vs > mmap.tell(). I have a generator that returns stuff from the file, > piece by piece. Since other things may happen to the mmap object in > between consecutive next() calls (such as another iterator's next()), > i have to store the file position before yield and restore it > afterwards by means of tell() and seek(). Is this correct? > > When restoring, is there a penalty for mmap.seek(pos) where the file > position is already at pos (i.e., nothing happened to the file > position in between, a common scenario)? If there is, is it worth > doing > > if mmap.tell() != pos: > mmap.seek(pos) > > or such? >
Measure it and see. I suspect that the cost of the check in Python will outweigh any extra work the C code might do, but you should never guess - just measure it. This is also pretty unlikely to be any sort of hotspot in your application - again, measure and see. Unless your profiler says you spend a lot of time in mmap.seek calls, don't worry about it. -- http://mail.python.org/mailman/listinfo/python-list
