Re:PCID is now a critical performance/security feature on x86
by snaky on Monday January 08, 2018 @10:10PM
(#16103268)
> I did manage to pull out an old Lenovo ThinkPad W510 with an Intel Core i7 720QM Clarksfield that is from 2009 and lacks PCID but is affected by this cpu_insecure issue.
> On that old Clarksfield-era ThinkPad I wasn't going to be surprised if the performance was disastrous, but it wound up being better than I had anticipated given all the ongoing drama... In general purpose workloads there was no reportable performance difference in our frequent benchmark test cases. Under I/O, the PTI-using kernel did yield some slower results but not by the margins seen on the newer systems with faster storage. The laptop consumer-grade HDD in this laptop appeared to be the main bottleneck and kernel inefficiencies weren't causing as dramatic slowdowns.
> To some surprise, when carrying out network benchmarks with netperf/iperf3, in at least those contexts PTI didn't have a noticeable impact on the network throughput performance.
> On that old Clarksfield-era ThinkPad I wasn't going to be surprised if the performance was disastrous, but it wound up being better than I had anticipated given all the ongoing drama... In general purpose workloads there was no reportable performance difference in our frequent benchmark test cases. Under I/O, the PTI-using kernel did yield some slower results but not by the margins seen on the newer systems with faster storage. The laptop consumer-grade HDD in this laptop appeared to be the main bottleneck and kernel inefficiencies weren't causing as dramatic slowdowns.
> To some surprise, when carrying out network benchmarks with netperf/iperf3, in at least those contexts PTI didn't have a noticeable impact on the network throughput performance.
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