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SubjectRe: [BK-2.5] Move "used FPU status" into new non-atomic thread_info->status field.
From
   From: Linus Torvalds <torvalds@transmeta.com>
Date: Mon, 10 Mar 2003 11:25:55 -0800 (PST)

> Are you preserving FPU state across fork() on x86? If so, what do you
> think might rely on this?

Probably nothing per se. HOWEVER, we'd still need to save the state for
rounding etc, so we might as well save it all.

I see.

We preserve the rounding/etc. modes on sparc, we merely zap the actual
FPU registers around the system call.

And that's like 4 L2 cache lines of registers on sparc64, so there
really is a benefit from only saving the mode register across a system
call.
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