2008-01-18 19:22:42 slow uclibc sin function
Doug Bailey (UNITED STATES)
Message: 49820 I have been running into some very slow execution times using the standard sin and cos function from uclibc. I am running an applet that I have incorporated into busybox) I have compiled using -mfast-fp and still have not seen any improvement.
I have noticed libbfdsp but I believe that it does not provide any standard sin function.
My distro is 1 year old but I did not see anything in the later tags that showed me a better way.
Any suggestions?
Regards,
Doug Bailey
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2008-01-18 19:34:31 Re: slow uclibc sin function
Mike Frysinger (UNITED STATES)
Message: 49821 well, it's all being done in double precision which is emulated in software, so any function found in libm is going to be dirt slow on the Blackfin
-mfast-fp only affects the code it compiles, so it'll optimize and code *you* write, but since uClibc wasnt built with it, none of the libm code will be affected
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2008-01-18 20:03:30 Re: slow uclibc sin function
Robin Getz (UNITED STATES)
Message: 49822 Try:
<code>-ffast-math -mfast-fp</code>
http://docs.blackfin.uclinux.org/doku.php?id=whetstone
Shows the results that can be expected - but as Mike states - You would need to rebuild the toolchain with these on to see the biggest improvement (which I don't think anyone has tried - If that is something you want to us to investigate - let me know).
-Robin