P140 changes the I-cache background repair policy instead of only counting it. Each foreground I-cache fill starts repair at the adjacent word, but the descriptor gets a budget of one word and then stops.
The shell workload passes and reaches P140-FILE-OK. The shell window
improves from P139’s 65,708,764 cycles to 65,035,481 cycles, a 673,283
cycle recovery.
The policy does what it was supposed to do: repair fills fall from 52,847,191 to 32,047,006, and first-hit usefulness improves from 3.64% to 4.12%.
But it also throws away too much line locality. I-cache hits fall hard and miss refills rise. This is not the final policy. The next rung should allow a second repair word only when there is evidence the line is actually on the fetch path.