在Oracle Linux上安装dtrace

在Oracle Linux上使用DTrace可以帮你
    观察整个软件体系、操作系统内核、系统库和应用程序的动态运行时性能
    通过在运行时定义实时探测点识别性能瓶颈
    开发探测器在谓词控制下触发时执行的脚本
    检测并报告内存访问错误，而不是听任系统崩溃

如何安装dtrace

一般情况下，DTrace软件包不能从Public yum上获取，必须先注册ULN(Unbreakable Linux Network)，然后才能下载和安装

yum install dtrace-utils

注意：在安装dtrace-utils之前需要安装dtrace-modules(这个可以从公共yum上获取)

其实只需要一个dtrace-utils的包，需要这个包做测试的，可以发信息给我(只限测试学习测试使用)

[root@ovm ~]# rpm -ivh dtrace-utils-0.5.0-4.el6.x86_64.rpm
Preparing...                ########################################### [100%]
   1:dtrace-utils           ########################################### [100%]
[root@ovm ~]#
[root@ovm ~]# ls -l /usr/sbin/dtrace
-rwxr-xr-x. 1 root root 36880 Nov  4  2015 /usr/sbin/dtrace
[root@ovm ~]# 

[root@ovm ~]# dtrace
Usage: dtrace [-32|-64] [-aACeFGhHlqSvVwZ] [-b bufsz] [-c cmd] [-D name[=def]]
        [-I path] [-L path] [-o output] [-p pid] [-s script] [-U name]
        [-x opt[=val]] [-X a|c|s|t]

        [-P provider [[ predicate ] action ]]
        [-m [ provider: ] module [[ predicate ] action ]]
        [-f [[ provider: ] module: ] func [[ predicate ] action ]]
        [-n [[[ provider: ] module: ] func: ] name [[ predicate ] action ]]
        [-i probe-id [[ predicate ] action ]] [ args ... ]

        predicate -> '/' D-expression '/'
           action -> '{' D-statements '}'

        -32 generate 32-bit D programs and ELF files
        -64 generate 64-bit D programs and ELF files

        -a  claim anonymous tracing state
        -A  generate driver.conf(4) directives for anonymous tracing
        -b  set trace buffer size
        -c  run specified command and exit upon its completion
        -C  run cpp(1) preprocessor on script files
        -D  define symbol when invoking preprocessor
        -e  exit after compiling request but prior to enabling probes
        -f  enable or list probes matching the specified function name
        -F  coalesce trace output by function
        -G  generate an ELF file containing embedded dtrace program
        -h  generate a header file with definitions for static probes
        -H  print included files when invoking preprocessor
        -i  enable or list probes matching the specified probe id
        -I  add include directory to preprocessor search path
        -l  list probes matching specified criteria
        -L  add library directory to library search path
        -m  enable or list probes matching the specified module name
        -n  enable or list probes matching the specified probe name
        -o  set output file
        -p  grab specified process-ID and cache its symbol tables
        -P  enable or list probes matching the specified provider name
        -q  set quiet mode (only output explicitly traced data)
        -s  enable or list probes according to the specified D script
        -S  print D compiler intermediate code
        -U  undefine symbol when invoking preprocessor
        -v  set verbose mode (report stability attributes, arguments)
        -V  report DTrace API version
        -w  permit destructive actions
        -x  enable or modify compiler and tracing options
        -X  specify ISO C conformance settings for preprocessor
        -Z  permit probe descriptions that match zero probes        
[root@ovm ~]# 

探测器和提供程序

要使用DTrace，需要指定内核中感兴趣的位置(称为探测器)，DTrace可以绑定一个请求来执行一组操作，如记录堆栈跟踪、时间戳或函数参数。探测器的作用类似于深埋于操作系统中用于记录信息的可编程遥感传感器。探测器触发时，DTrace会从其收集数据并向您回报数据。Oracle Linux DTrace探测器运行于被称作提供程序的DTrace内核模块中，提供程序执行插装以支持探测器。

# modprobe systrace

[root@ovm ~]# dtrace -l|wc -l
622
[root@ovm ~]#
[root@ovm ~]# dtrace -l|more
   ID   PROVIDER            MODULE                          FUNCTION NAME
    1     dtrace                                                     BEGIN
    2     dtrace                                                     END
    3     dtrace                                                     ERROR

    provider  — 发布此探测器的 DTrace 提供程序的名称。提供程序名称通常对应于执行插装以启用探测器的 DTrace 内核模块的名称
    module    — 如果此探测器对应于特定程序位置，则为探测器所在内核模块的名称
    function  — 如果此探测器对应于特定程序位置，则为探测器所在程序函数的名称
    name      — 探测器名称的最后一部分，即表明探测器语义的名称

# New processes with arguments
dtrace -n 'proc:::exec-success { trace(curpsinfo->pr_psargs); }'

# Files opened by process
dtrace -n 'syscall::open*:entry { printf("%s %s",execname,copyinstr(arg0)); }'

# Syscall count by program
dtrace -n 'syscall:::entry { @num[execname] = count(); }'

# Syscall count by syscall
dtrace -n 'syscall:::entry { @num[probefunc] = count(); }'

# Syscall count by process
dtrace -n 'syscall:::entry { @num[pid,execname] = count(); }'

# Disk size by process
dtrace -n 'io:::start { printf("%d %s %d",pid,execname,args[0]->b_bcount); }'

# Pages paged in by process
dtrace -n 'vminfo:::pgpgin { @pg[execname] = sum(arg0); }'

[root@ovm ~]# cat syscalls.d
#!/usr/sbin/dtrace -qs
syscall:::entry
/pid == $1/
{
  @num[probefunc] = count();
}
[root@ovm ~]# ./syscalls.d 3961
^C

  rt_sigreturn                                                      1
  shutdown                                                          1
  accept                                                            2
  clone                                                             3
  connect                                                           3
  gettid                                                            3
  set_robust_list                                                   3
  socket                                                            3
  exit                                                              4
  getsockopt                                                        4
  getsockname                                                       5
  madvise                                                           5
  close                                                             6
  dup2                                                              6
  sched_getaffinity                                                 6
  mmap                                                              7
  epoll_ctl                                                        10
  rt_sigprocmask                                                   13
  setsockopt                                                       13
  fcntl                                                            15
  write                                                            17
  read                                                             23
  epoll_wait                                                       39
  mprotect                                                         51
  newstat                                                          84
  ioctl                                                            95
  poll                                                            140
  sendto                                                          265
  recvfrom                                                        284
  futex                                                          1714
[root@ovm ~]# 

https://github.com/dtrace4linux/linux