Re: irq_fpu_usable() is irreliable
From: Ingo Molnar
Date: Wed Nov 18 2015 - 01:55:21 EST
* Jason A. Donenfeld <Jason@xxxxxxxxx> wrote:
> [...] Recently I've been tracking down a problem in which irq_fpu_usable()
> returns false, yet a stack trace shows the first function is the syscall entry
> point. [...]
Is this 'problem' a performance problem (code not being able to use the FPU
occasionally and hence sporadically performing poorly), or some sort of actual
stability/correctness problem?
Also, what CPU does the test system have, Intel or AMD? The FPU behavior can be
very different in the two cases.
Third, could you post such a problematic stack trace?
Thanks,
Ingo
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