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Linux Performance tools
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.. include:: ../links.ref
.. include:: ../tags.ref
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============ ==========================
**Abstract** Linux Performance tools
**Authors**  Walter Fan
**Status**   v1
**Updated**  |date|
============ ==========================



.. contents::
   :local:


简介
=========================

A miscellaneous collection of in-development and unsupported performance analysis tools for Linux ftrace and perf_events 

(aka the "perf" command). Both ftrace and perf are core Linux tracing tools, included in the kernel source. 

.. image:: ../_static/perf-tools_2016.png


Using ftrace
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* iosnoop: trace disk I/O with details including latency
* iolatency: summarize disk I/O latency as a histogram
* execsnoop: trace process exec() with command line argument details
* opensnoop: trace open() syscalls showing filenames
* killsnoop: trace kill() signals showing process and signal details
* fs/cachestat: basic cache hit/miss statistics for the Linux page cache
* net/tcpretrans: show TCP retransmits, with address and other details
* system/tpoint: trace a given tracepoint
* kernel/funccount: count kernel function calls, matching a string with wildcards
* kernel/functrace: trace kernel function calls, matching a string with wildcards
* kernel/funcslower: trace kernel functions slower than a threshold
* kernel/funcgraph: trace a graph of kernel function calls, showing children and times
* kernel/kprobe: dynamically trace a kernel function call or its return, with variables
* user/uprobe: dynamically trace a user-level function call or its return, with variables
* tools/reset-ftrace: reset ftrace state if needed
  
Using perf_events
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* misc/perf-stat-hist: power-of aggregations for tracepoint variables
* syscount: count syscalls by syscall or process
* disk/bitesize: histogram summary of disk I/O size

Using eBPF
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As a preview of things to come, see the bcc tracing Tools section. These use bcc, a front end for using eBPF. 
bcc+eBPF will allow some of these tools to be rewritten and improved, and additional tools to be created.


Reference
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* https://github.com/brendangregg/perf-tools
* https://www.brendangregg.com/perf.html
* https://www.slideshare.net/brendangregg/linux-performance-analysis-new-tools-and-old-secrets