Intel Posts Linux Perf Support For Icelake CPUs

With the core functionality for Intel Icelake CPUs appearing to be in place, Intel's open-source developers have been working on the other areas of hardware enablement for these next-generation processors.

The latest Icelake Linux patches we are seeing made public by Intel is in regards to the "perf" subsystem support. Perf, of course, is about exposing the hardware performance counters and associated instrumentation that can be exercised by user-space when profiling performance of the hardware and other events.

With 22 new patches, the Linux kernel's perf support for Icelake is put into shape.

The perf/counter capabilities are greater with Icelake than previous generations of Intel CPUs. As to some of the changes exposed by these patches: "Icelake expanded the generic counters to always 8 even with HT on, but a range of events cannot be scheduled on the extra 4 counters. Add new constraint ranges to describe this to the scheduler. The number of constraints that need to be checked is larger now than with earlier CPUs. At some point we may need a new data structure to look them up more efficiently than with linear search. So far it still seems to be acceptable however." Also, Icelake has support for reporting per-thread top-down metrics.

Intel Icelake CPUs will hopefully be shipping before the end of the calendar year.