[wayne@cs.toronto.edu: Cygwin-1.5.5 sscanf on floats: 20 times slower than 2 years ago]

J. Johnston jjohnstn@redhat.com
Fri Nov 21 23:45:00 GMT 2003


J. Johnston wrote:
> Wayne Hayes wrote:
> 
>>> Since scanf and the floating point arithmetic is implemented in newlib,
>>> I've redirected this message there.  Does anybody have an idea, what
>>> could slow down float scanning in sscanf by a factor of 20?
>>
>>
>>
>> Thanks!  Just to be pedentic, I realized that it's worse than a factor 
>> of 20.
>> My *entire simulation* slows down by a factor of 20; there's significant
>> other computation in it.  So the scanf slowdown is probably closer to
>> hundreds of times.  *Something* fishy must be going on.  :-)
>>
> 
> The reason for the slow down is long double support.  A new routine 
> _strtold is used instead of _strtod_r.  I am working on a patch to use 
> the old routine for non-long-doubles to avoid the slow down.
> 
> -- Jeff J.
>

Patch checked in.

-- Jeff J.




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