Spectre/Meltdown fixes in HPC: Want the bad news or the bad news? It's slower, say boffins

MIT Lincoln metalheads broke big iron so you don't have to… oh, you still have to, don't you?
July 26, 2018
The Register

HPC admin? Feeling slighted that all the good Spectre/Meltdown mitigation benchmarks ignore big iron? Fear not, a bunch of MIT boffins are on your side.

Unfortunately, what they found is that network connections, disk accesses, and computational workloads can all be affected by the fixes, whether in the operating system or the microcode.

Within a week of the twin bugs being published, performance has been on everyone's mind – because speculative execution is a long-standing performance feature in microprocessors.

Amazon almost immediately warned of performance hits, echoed quickly by others in the industry. Intel responded that performance impacts would depend on workload. SolarWinds conducted its own tests on AWS, and Netflix thought the damage could be contained.

None of those tests were wholly relevant to HPC workloads, however, so an 18-member team from MIT's Lincoln Laboratory set to work on their own.