[firstname.lastname@example.org: cygwin-1.5.5 sscanf on floats: 20 times slower than 2 years ago]
Sat Nov 22 00:38:00 GMT 2003
On Fri, Nov 21, 2003 at 03:50:18PM -0500, J. Johnston wrote:
>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
>>>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.
>Patch checked in.
I'm generating a new snapshot now: http://cygwin.com/snapshots.html .
It will be interesting to hear if this solves the problem.
Btw, would using hardware floating point help here at all? I managed to
get newlib to build with hardware floating point earlier but I wasn't
sure what the consequences of doing that would be (other than the fact
that cygwin wouldn't work on a x386).
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