perf

简介

perf 是一个 Linux 系统中的性能分析工具，支持硬件性能计数、软件性能计数和动态侦测。

安装

• 通过 apt 直接进行安装

$ sudo apt install linux-tools-generic linux-tools-`uname -r`

• 或者，通过源码编译安装

$ cd <linux kernel>/tools/perf
$ make
$ make prefix=/usr/local install

参数解析

$ perf stat [command]        ## Run a command and gather performance counter statistics
                   -a        ## system-wide collection from all CPUs
                   -p <pid>  ## stat events on existing process id
                   -t <tid>  ## stat events on existing thread id

$ perf top                   ## System profiling tool.
                   -a        ## system-wide collection from all CPUs
                   -p <pid>  ## profile events on existing process id
                   -t <tid>  ## profile events on existing thread id
                   -U        ## hide user symbols

$ perf record [command]      ## Run a command and record its profile into perf.data
                   -a        ## system-wide collection from all CPUs
                   -p <pid>  ## record events on existing process id
                   -t <tid>  ## record events on existing thread id
                   -o <file> ## output file name
                   -g        ## enables call-graph recording
$ perf report                ## Read perf.data and display the profile
                   -i <file> ## input file name
                   -k <file> ## vmlinux pathname
$ perf script                ## unfold perf.data
                   -i <file> ## input file name
                   -k <file> ## vmlinux pathname

$ perf sched record [command]               ## record the scheduling events of an arbitrary workload
$ perf sched latency                        ## report the per task scheduling latencies
                   -i <file>                ## input file name
                   -p                       ## latency stats per pid instead of per command name
                   -s <key>                 ## sort by keys, default "avg,max,switch,runtime"

$ perf kwork record [command]               ## record the kernel work of an arbitrary workload
$ perf kwork report                         ## report the per kwork runtime
$ perf kwork latency                        ## report the per kwork latencies

$ perf diff <options> [baseline] [file1]    ## baseline vs file1, display the differential profile.
                                            ## default perf.data.old vs perf.data
            -c <delta, delta-abs>           ## Entries differential computation selection. default delta-abs

例子

$ perf top -U -a              ## 显示内核空间的热点函数

$ perf record -g -a           ## 生成采样数据 perf.data
$ perf report                 ## 解析 perf.data