Jack Liu's Github地址:
https://github.com/ljq/jackliu-golang-notes/blob/master/zh_CN/tool-pprof.md
Go tool pprof使用方式
go中有pprof包来做代码的性能监控主要涉及两个pkg：
#web服务器:
import (
"net/http"
_ "net/http/pprof"
)
#一般应用程序(实际应用无web交互)
import (
"net/http"
_ "runtime/pprof"
)
net/http/pprof中只是使用runtime/pprof包来进行封装了一下，并在http端口上暴露出来。
Go tool pprof辅助工具安装(图形工具graphviz为例)
Windows：
1.官方下载安装包: http://www.graphviz.org/download/
下载Stable稳定版本(.msi)
2.配置PATH系统环境变量：
C:\Program Files (x86)\Graphviz2.38\binLinux(例：Centos)
方式1).添加repo依赖http://204.178.9.49/graphviz-rhel.repo
yum list available 'graphviz*'
yum install 'graphviz*' --skip-broken
#备注：--skip-broken可选：跳过错误依赖，不加这个参数会提示安装包依赖错误，因为这里并不需要其它的安装包，所以跳过即可。
--skip-broken可选：跳过错误依赖，不加这个参数会提示安装包依赖错误，因为这里并不需要其它的安装包，所以跳过即可。
方式2).源码包编译安装
./configure
make
make install
-
MacOS:
brew install graphviz
Go tool pprof常用基本调试基本命令(默认30s采集时间，可通过--seconds)
HTTP场景(参数可选:--text)：
Heap profile:
go tool pprof --text http://localhost:8080/debug/pprof/heap
CPU profile:
go tool pprof --text http://localhost:8080/debug/pprof/profile
Goroutine blocking profile:
go tool pprof --text http://localhost:8080/debug/pprof/block
1.实时通过地址查看浏览器: http://localhost:8080/debug/pprof/;
2.通过生成的profile文件分析;
选择指定的profile压缩gz文件(.gz),使用go tool pprof进入
go tool pprof http://localhost:8080/debug/pprof/profile
#结束后直接进入交互：
(pprof)
web
(pprof)
如查看历史调试文件信息，通过指定的profile文件进入即可:
go tool pprof [*.gz]
pprof交互基本命令：web 直接生成web浏览器可访问的svg图;
(其他命令自行摸索)
Windows下自动生成.svg文件且调用默认浏览器访问;
MacOS下自动生成.gz文件，系统限制可根据提示文件路径通过手动访问查看;
【注意事项】：
profile文件为空的问题, heap和block一般不受影响。
执行交互web命令会报:
(pprof) web
profile is empty
(pprof)
产生原因：
pprof内存分析器采取抽样的方式，它仅仅从一些内存分配的子集中收集信息。有可能对一个对象的采样与被采样对象的大小成比例。通过使用go test --memprofilerate标识，或者通过程序启动时 的运行配置中的MemProfileRate变量来改变调整这个采样的比例。如果比例为1，则会导致全部申请的信息都会被收集，但是这样的话将会使得执行变慢。默认的采样比例是每512KB的内存申请就采样一次。
- 方法1).在进行调试时，指定运行参数，或运行代码中动态调整参数
go tool pprof --text http://localhost:8080/debug/pprof/profile
此命令将会打印耗费最多CPU时间的函数列表。
这里有几种可用的输出形式，最实用的有 --text, --web 和 --list。运行 "go tool pprof" 来得到完整的列表。
【备注】：
实际测试时，MacOS下基本是空的,需要指定参数。
方法2).设置环境变量(此方法极不推荐!)设置Go环境变量 GODEBUG="memprofilerate=1".
通过控制采样的比例和行为，可以达到性能调试粒度的控制！
附pprof 交互命令help说(部分命令需要第三方工具支持)：
(pprof) help
Commands:
cmd [n] [--cum] [focus_regex]* [-ignore_regex]*
Produce a text report with the top n entries.
Include samples matching focus_regex, and exclude ignore_regex.
Add --cum to sort using cumulative data.
Available commands:
callgrind Outputs a graph in callgrind format
disasm Output annotated assembly for functions matching regexp or address
dot Outputs a graph in DOT format
eog Visualize graph through eog
evince Visualize graph through evince
gif Outputs a graph image in GIF format
gv Visualize graph through gv
list Output annotated source for functions matching regexp
pdf Outputs a graph in PDF format
peek Output callers/callees of functions matching regexp
png Outputs a graph image in PNG format
proto Outputs the profile in compressed protobuf format
ps Outputs a graph in PS format
raw Outputs a text representation of the raw profile
svg Outputs a graph in SVG format
tags Outputs all tags in the profile
text Outputs top entries in text form
top Outputs top entries in text form
tree Outputs a text rendering of call graph
web Visualize graph through web browser
weblist Output annotated source in HTML for functions matching regexp or address
peek func_regex
Display callers and callees of functions matching func_regex.
dot [n] [focus_regex]* [-ignore_regex]* [>file]
Produce an annotated callgraph with the top n entries.
Include samples matching focus_regex, and exclude ignore_regex.
For other outputs, replace dot with:
- Graphic formats: dot, svg, pdf, ps, gif, png (use > to name output file)
- Graph viewer: gv, web, evince, eog
callgrind [n] [focus_regex]* [-ignore_regex]* [>file]
Produce a file in callgrind-compatible format.
Include samples matching focus_regex, and exclude ignore_regex.
weblist func_regex [-ignore_regex]*
Show annotated source with interspersed assembly in a web browser.
list func_regex [-ignore_regex]*
Print source for routines matching func_regex, and exclude ignore_regex.
disasm func_regex [-ignore_regex]*
Disassemble routines matching func_regex, and exclude ignore_regex.
tags tag_regex [-ignore_regex]*
List tags with key:value matching tag_regex and exclude ignore_regex.
quit/exit/^D
Exit pprof.
option=value
The following options can be set individually:
cum/flat: Sort entries based on cumulative or flat data
call_tree: Build context-sensitive call trees
nodecount: Max number of entries to display
nodefraction: Min frequency ratio of nodes to display
edgefraction: Min frequency ratio of edges to display
focus/ignore: Regexp to include/exclude samples by name/file
tagfocus/tagignore: Regexp or value range to filter samples by tag
eg "1mb", "1mb:2mb", ":64kb"
functions: Level of aggregation for sample data
files:
lines:
addresses:
unit: Measurement unit to use on reports
Sample value selection by index:
sample_index: Index of sample value to display
mean: Average sample value over first value
Sample value selection by name:
alloc_space for heap profiles
alloc_objects
inuse_space
inuse_objects
total_delay for contention profiles
mean_delay
contentions
: Clear focus/ignore/hide/tagfocus/tagignore
(pprof)
