> Well... maybe. On Opteron and/or Intel EMT it may not be a win. The
> cost of the branch could overtake the cost of the POPF (that's the
> expensive one). Grrr.
Not on Opteron, but probably on Intel.
iirc popf will actually flush parts of the trace cache, while
a branch shouldn't do that.
Andi Kleen wrote:
[EMAIL PROTECTED] writes:
Unfortunately, this added one field to the thread_struct. But as a bonus, on
P4, the fastest time measured for switch_to() went from 312 to 260 cycles, a
win of about 17% in the fast case through this performance critical path.
Cool! Defini
[EMAIL PROTECTED] writes:
>
> Unfortunately, this added one field to the thread_struct. But as a bonus, on
> P4, the fastest time measured for switch_to() went from 312 to 260 cycles, a
> win of about 17% in the fast case through this performance critical path.
Cool! Definitely want this on x86-
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