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Re: [patch] tuning gcc for Intel Core2
Andi Kleen wrote:
I tried these parameters and got better results (although I don't
remeber exact numbers). Actually I've tried all parameters. I started
the work when intel's guide was not public so I had to try all parameters.
Even if Core2 has special hardware to decrease problem of dependencies
on stack pointer, it does not mean that usage of push/pop will be better.
According to the guide PUSH has latency 1.5 (whatever that means)
and MOV 1. No extra dependencies on the stack pointer because those
are optimized away early in the pipeline.
1.5 is for Core, the latency for Core2 is missed in the table.
The advantage would be smaller code.
But utilization one more functional unit (although partially it will be
improved by out-of-order execution).