What is perf in kernel?

What is perf in kernel?

Perf is a profiler tool for Linux 2.6+ based systems that abstracts away CPU hardware differences in Linux performance measurements and presents a simple commandline interface. Output was obtained on a Ubuntu 11.04 system with kernel 2.6.

What is kernel configuration?

The Linux kernel configuration is usually found in the kernel source in the file: /usr/src/linux/. config . It is not recommended to edit this file directly but to use one of these configuration options: make menuconfig – starts a terminal-oriented configuration tool (using ncurses) …

What is perf used for?

The perf tool can be used to collect profiles on per-thread, per-process and per-cpu basis. There are several commands associated with sampling: record, report, annotate. You must first collect the samples using perf record. This generates an output file called perf.

What is perf script?

‘perf script’ to see a detailed trace of the workload that was recorded. You can also run a set of pre-canned scripts that aggregate and summarize the raw trace data in various ways (the list of scripts is available via ‘perf script -l’).

How do I change the kernel configuration file?

1 Answer

1. make _defconfig.
2. make menuconfig. edit. exit saving changes.
3. make savedefconfig. creates a file named defconfig.
4. cp defconfig arch/$ARCH/configs/_defconfig. where $ARCH is the CPU architecture, e.g. arm.

What is perf programming?

Performance programming seeks to improve performance beyond what is achieved by programming an algorithm in the most expedient manner. The goal is that each processing element be kept as busy as possible doing useful work.

How does perf work in linux?

Perf overview Perf is a facility comprised of kernel infrastructure for gathering various events and userspace tool to get gathered data from the kernel and analyze it. It is like a gprof, but it is non-invasive, low-overhead and profile the whole stack, including your app, libraries, system calls AND kernel with CPU!

How do I get perf in Linux?

In this case, download the required linux kernel version (our case is v4. 4.77) and go to ‘linux->tools->perf’ to install it. After doing this, you can try $perf –version and hope it works for you now. After make , you can also try make install and then check the perf –version .

What is a perf file?

Perf consists of kernel code and an userspace tool. The tool records the data to an file which can be analyzed later. This report provides information about the data structures used to read the data file. An application was written to demonstrate how the data file can be read.

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).

Where do I find the Perf configuration file?

CONFIGURATION FILE top The perf configuration file contains many variables to change various aspects of each of its tools, including output, disk usage, etc. The $HOME/.perfconfig file is used to store a per-user configuration. The file $ (sysconfdir)/perfconfig can be used to store a system-wide default configuration.

How to get kernel sample with perf binary?

To get kernel and user samples with a perf binary with just CAP_PERFMON. As a result, members of perf_users group are capable of conducting performance monitoring and observability by using functionality of the configured Perf tool executable that, when executes, passes perf_events subsystem scope checks.

What are the default colors in PERF config ( 1 )?

Default values are magenta, default . colors.root Colors for headers in the output of a sub-commands (top, report). Default values are white, blue . core.*, core.proc-map-timeout Sets a timeout (in milliseconds) for parsing /proc/ /maps files.