Re: Spinlocks, yet again: analysis and proposed patches

Tom, et al.,

Updated, with full recompiles between everything and the new
modification:

N, runtime:
Tip: 1 31s 2 37s 4 86s 8 159s
no-cmpb: 1 32s 2 43s 4 83s 8 168s
spin: 1 32s 2 51s 4 84s 8 160s
spin+mod: 1 32s 2 51s 4 89s 8 158s
spin+no-cmpb: 1 32s 2 51s 4 87s 8 163s
spin+mod+no-cmpb: 1 32s 2 50s 4 86s 8 161s

Unfortunately, the results don't seem to be terribly consistent between
runs anyway:

Run 2:
Tip: 1 32s 2 43s 4 87s 8 160s
no-cmpb: 1 31s 2 47s 4 83s 8 167s
spin: 1 32s 2 52s 4 88s 8 154s
spin+no-cmpb: 1 32s 2 51s 4 102s 8 166s
spin+mod: 1 32s 2 53s 4 85s 8 154s
spin+mod+no-cmpb: 1 32s 2 51s 4 91s 8 161s

Hope it helps,

Stephen