Looking at 17% loss on everything now with the patches: https://lkml.org/lkml/2018/1/3/281
Yep. "The impact of this will vary depending on the workload. Every time a program makes a call into the kernel—to read from disk, to send data to the network, to open a file, and so on—that call will be a little more expensive, since it will force the TLB to be flushed and the real kernel page table to be loaded. Programs that don't use the kernel much might see a hit of perhaps 2-3 percent—there's still some overhead because the kernel always has to run occasionally, to handle things like multitasking.
But workloads that call into the kernel a ton will see much greater performance drop off. In a benchmark, a program that does virtually nothing other than call into the kernel saw its performance drop by about 50 percent; in other words, each call into the kernel took twice as long with the patch than it did without. Benchmarks that use Linux's loopback networking also see a big hit, such as 17 percent in this Postgres benchmark. Real database workloads using real networking should see lower impact, because with real networks, the overhead of calling into the kernel tends to be dominated by the overhead of using the actual network"
I wonder if the i5/i7 in a MacBookPro6,1 (running Snow Leopard) is affected by this? Or this only happens on newer cpus?