Re:Intel i7 loop performance anomaly
by nkurz on Wednesday December 04, 2013 @03:55AM
(#6845773)
both loops should fit in the loop buffer, which is after the u-op cache, and so wouldn't suffer from the 18-uop limit mentioned above
Both loops should fit, but I think the same limits for micro-op density apply. The Optimization Manual says the Loop Stream Detector requires that "All micro-ops are also resident in the Decoded ICache". I took this to mean if something can't be cached by the Decoded ICache, it can't be streamed by the LSD.
Both loops should fit, but I think the same limits for micro-op density apply. The Optimization Manual says the Loop Stream Detector requires that "All micro-ops are also resident in the Decoded ICache". I took this to mean if something can't be cached by the Decoded ICache, it can't be streamed by the LSD.