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List:       freebsd-hackers
Subject:    floating point operations
From:       James Healy <jhealy () swin ! edu ! au>
Date:       2007-10-31 23:40:04
Message-ID: 47291254.9030909 () swin ! edu ! au
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hackers,

We've been making experimental changes to FreeBSD's TCP congestion
control code, and we used a few floating point operations initially in
our prototype.

We've since gone back and converted all but one of the operations to
fixed point maths in following the no-flops-in-kernel mantra.

The remaining op is not easily converted to fixed point math, and we're
wondering what impact a single flop on the receipt of each ACK will
have. We don't have a strong understanding of the amount of overhead
involved in executing a flop instead of an int op on modern hardware.

regards

James Healy
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