KPTI + Retpoline Linux Benchmarking On Old Laptops

Over the past week and a half of running many benchmarks looking at the performance impact of the Linux KPTI and Retpoline patches for Spectre and Meltdown mitigation, one of the most common test requests is some thorough benchmarks on older systems. Why that's important is with older (pre-Westmere) CPUs there isn't PCID (Process Context Identifier) support that's used by KPTI, which helps offset some of the performance loss. So for some test results to share today are two old ThinkPads from the Clarksfield and Penryn days compared to a newer Broadwell ThinkPad in looking at the performance difference.