What is perf used for?

Table of Contents

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. Perf is based on the perf_events interface exported by recent versions of the Linux kernel.

How does Linux perf work?

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 read a perf data file?

There is builtin perf. data parser and printer in perf tool of linux tools with subcommand “script”. perf-script – Read perf. data (created by perf record) and display trace output This command reads the input file and displays the trace recorded.

What is perf top?

DESCRIPTION top This command generates and displays a performance counter profile in real time.

What is Python perf?

The python-perf package contains a module that permits applications written in the Python programming language to use the interface to manipulate perf events.

What is a perf file?

The perf record tool is used to capture events and write them into a data file. By default, the data file has the name perf. data and is in the current working directory. It was used to capture all applications on all CPU’s with timestamps. The command line to achieve this is perf record -a -T 1.

What is perf in programming?

The perf command perf is a very powerful userspace command for tracing or counting both hardware and software events. Software events are predefined in the kernel, can be predefined in userspace code, and can be dynamically created (as “probes”) in kernel or userspace code.

What is overhead in perf report?

Overhead: the percentage of overall samples collected in the corresponding function. Command: the command to which the samples belong. Shared object: the name of the image from where the samples came. Symbol: the symbol name which constitutes the sample, and the privilege level at which the sample was taken.

How do you annotate perf?

You can also annotate using the perf top command. Run the perf top command and press ‘a’ on any particular symbol that you want to annotate. It also dynamically updates data at a fixed interval.

What is perf event?

perf_events provides a command line tool, perf, and subcommands for various profiling activities. This is a single interface for the different instrumentation frameworks that provide the various events. The perf command alone will list the subcommands; here is perf version 4.10 (for the Linux 4.10 kernel):

How do I investigate CPU usage in Linux?

How To Check CPU Usage from Linux Command Line. top Command to View Linux CPU Load. mpstat Command to Display CPU Activity. sar Command to Show CPU Utilization. iostat Command for Average Usage.
Other Options to Monitor CPU Performance. Nmon Monitoring Tool. Graphical Utility Option.

How do I make Python run faster?

A Few Ways to Speed Up Your Python Code

Use proper data structure. Use of proper data structure has a significant effect on runtime.
Decrease the use of for loop.
Use list comprehension.
Use multiple assignments.
Do not use global variables.
Use library function.
Concatenate strings with join.
Use generators.

How do I resolve high CPU utilization in Linux?

Use Alternative App. The good thing about Linux is that there are many apps that can do the same thing. So if one app is causing high CPU usage, you can and should replace it with an alternative.

How do I investigate high CPU in Linux?

The old good top command to find out Linux CPU Utilization

Top command to find out Linux cpu usage.
Say hello to htop.
Display the utilization of each CPU individually using mpstat.
Report CPU utilization using the sar command.
Task: Find out who is monopolizing or eating the CPUs.
iostat command.
vmstat command.

Which Python interpreter is fastest?

Conclusion. Python 3.7 is the fastest of the “official” Python’s and PyPy is the fastest implementation I tested.

How do I make Python use more CPU?

Having said that, there are several ways to use multiple cores with python.

Built-in is the multiprocessing module. The multiprocessing.
Use a suitable build of numpy.
Use extension modules like numexpr, parallel python, corepy or Copenhagen Vector Byte Code.

Why is Linux CPU usage high?

The user CPU and Nice CPU are high, indicating that the user mode process occupies more CPU, so you should focus on the performance of the process. If the system CPU is high, it means that the kernel mode occupies more CPU, so you should focus on checking the performance of kernel threads or system calls.

How do I reduce high CPU usage in Linux?

Install CPULimit to Limit CPU Usage Of a Process in Linux. CPULimit is available to install from default software repositories of Debian/Ubuntu and its derivatives using a package management tool. In RHEL/CentOS and Fedora, you need to first enable EPEL repository and then install cpulimit as shown.

How does perf probe work without-m/-x options?

In absence of -m/-x options, perf probe checks if the first argument after the options is an absolute path name. If its an absolute path, perf probe uses it as a target module/target user space binary to probe.

How to use the Perf command?

Usage of perf Usage of perf command # perf [option] Commands Descriptions annotate Read perf.data* and display annotated code diff Read two perf.data* files and display the differential profile probe Define new dynamic trace-points record Run a command and record its profile into perf.data*

Who is the author of perf for user space program analysis?

Title Perf for User Space Program Analysis Author Tetsuo Takata Keywords perf, PostgreSQL, profiler, pmu, profiling, linux, kernel Created Date 6/21/2013 11:46:51 AM

What is your use case for OSS/perf?

•a use case of perf where we analyzed a performance problem of a middleware. Background: OSS has been used in many mission-critical systems, where every single problem must be fixed fast and accounted for, and where tools assisting troubleshooting is more important than anywhere else.