The “perf” kernel subsystem of Linux has gained some new AMD CPU functions in the Linux 6.1 version. The more important ones are perf mem (memory report) and perf c2c (Cache-To-Cache) two functions, of which the perf mem function uses For various memory statistics, and the perf c2c function is used for statistics of CPU cache-to-cache information.

Using the perf tool with new features, you can display memory L1/L2/L3 cache hit ratio, local RAM hit ratio, remote RAM hit ratio, remote cache hits, uncached hits, and other similar metrics. Note, however, that the latest perf c2c/mem support relies on AMD CPUs with Instruction Based Sampling (IBS) support.

Linux 6.1’s perf subsystem core changes also contain other features and optimizations such as Intel PEBS TSC timestamp integration, Intel Raptor Lake S CPU support, hardware breakpoint improvements, and other fixes.

All changes to the perf tool can be seen in the Git PR mail, including updated details for AMD perf mem/c2c, as well as improvements to perf lock/lock contention, Intel PT improvements, and more.

About perf

perf is a performance analysis tool for Linux systems that can perform function-level and instruction-level hot spot searches. It can be used to analyze the CPU usage of hot functions in the program to locate performance bottlenecks.

The “perf” of the Linux kernel is a kernel-based subsystem that provides a performance analysis framework, such as hardware (CPU, PMU (Performance Monitoring Unit)) functions and software (software counters, tracepoint) functions.

With perf, applications can take advantage of the PMU, tracepoints, and counters in the kernel for performance statistics.