Is the perf tool based on the Linux kernel?
Perf is based on the perf_events interface exported by recent versions of the Linux kernel. This article demonstrates the perf tool through example runs. Output was obtained on a Ubuntu 11.04 system with kernel 2.6.38-8-generic results running on an HP 6710b with dual-core Intel Core2 T7100 CPU).
What happens if there are more events than counters in PERF?
In that case, perf will report an error. See the troubleshooting section for help with this matter. If there are more events than counters, the kernel uses time multiplexing (switch frequency = HZ, generally 100 or 1000) to give each event a chance to access the monitoring hardware.
How to count hardware performance events in PERF?
As a compromise, the L1-dcache-loads and L1-dcache-stores events are mapped to the ARMv7 data read/write L1 data cache event. You are likely to find similar compromises on other processor implementations, too. Each processor core has a set of hardware performance counters which count performance events.
Which is an example of a perf profiler?
These are some examples of using the perf Linux profiler, which has also been called Performance Counters for Linux (PCL), Linux perf events (LPE), or perf_events. Like Vince Weaver, I’ll call it perf_events so that you can search on that term later.
How to compile a kernel module in GCC?
-DMODULE: This symbol tells the header files to give the appropriate definitions for a kernel module. In order to compile a kernel module, it is better to use the kernel Makefile resident in the Kernel source directory. You can use the following make command:
How to compile Linux kernel module without makefile?
This is additional info to delve into. Post 2.6 version, as mentioned in other reply the Makefile takes care of most of the Linux kernel module compilation steps. However, at the core of it is still GCC, and this is how it does: (you too may compile it without Makefile)
Can a perf tool be used to trace a CPU?
Typically, the kernel does not do particularly CPU intensive operations, making it possible to trace for longer periods. Tracing the kernel-only can be useful for analyzing latencies. perf tools support the ability to make snapshots of Intel PT trace.
https://www.youtube.com/watch?v=MaGkHGE9rwo