c 语言使用lttng | 易学教程

以下内容来自lttng 官方文档，主要是学习记录

创建tracepoint

hello-tp.h

 
         #undef TRACEPOINT_PROVIDER 
        
         #define TRACEPOINT_PROVIDER hello_world 
        
         ​ 
        
         #undef TRACEPOINT_INCLUDE 
        
         #define TRACEPOINT_INCLUDE "./hello-tp.h" 
        
         ​ 
        
         #if !defined(_HELLO_TP_H) || defined(TRACEPOINT_HEADER_MULTI_READ) 
        
         #define _HELLO_TP_H 
        
         ​ 
        
         #include <lttng/tracepoint.h> 
        
         ​ 
        
         TRACEPOINT_EVENT( 
        
             hello_world, 
        
             my_first_tracepoint, 
        
             TP_ARGS( 
        
                 int, my_integer_arg, 
        
                 char*, my_string_arg 
        
             ), 
        
             TP_FIELDS( 
        
                 ctf_string(my_string_field, my_string_arg) 
        
                 ctf_integer(int, my_integer_field, my_integer_arg) 
        
             ) 
        
         ) 
        
         ​ 
        
         #endif /* _HELLO_TP_H */ 
        
         ​ 
        
         #include <lttng/tracepoint-event.h>

hello-tp.c

 
         #define TRACEPOINT_CREATE_PROBES 
        
         #define TRACEPOINT_DEFINE 
        
         ​ 
        
         #include "hello-tp.h"

构建

gcc -c -I. hello-tp.c

c 应用
hello.c

 
         #include <stdio.h> 
        
         #include "hello-tp.h" 
        
         ​ 
        
         int main(int argc, char *argv[]) 
        
         { 
        
             int x; 
        
         ​ 
        
             puts("Hello, World!\nPress Enter to continue..."); 
        
         ​ 
        
             /* 
        
              * The following getchar() call is only placed here for the purpose 
        
              * of this demonstration, to pause the application in order for 
        
              * you to have time to list its tracepoints. It's not needed 
        
              * otherwise. 
        
              */ 
        
             getchar(); 
        
         ​ 
        
             /* 
        
              * A tracepoint() call. 
        
              * 
        
              * Arguments, as defined in hello-tp.h: 
        
              * 
        
              * 1. Tracepoint provider name   (required) 
        
              * 2. Tracepoint name            (required) 
        
              * 3. my_integer_arg             (first user-defined argument) 
        
              * 4. my_string_arg              (second user-defined argument) 
        
              * 
        
              * Notice the tracepoint provider and tracepoint names are 
        
              * NOT strings: they are in fact parts of variables that the 
        
              * macros in hello-tp.h create. 
        
              */ 
        
             tracepoint(hello_world, my_first_tracepoint, 23, "hi there!"); 
        
         ​ 
        
             for (x = 0; x < argc; ++x) { 
        
                 tracepoint(hello_world, my_first_tracepoint, x, argv[x]); 
        
             } 
        
         ​ 
        
             puts("Quitting now!"); 
        
             tracepoint(hello_world, my_first_tracepoint, x * x, "x^2"); 
        
         ​ 
        
             return 0; 
        
         }

构建

gcc -c hello.c

链接应用

gcc -o hello hello.o hello-tp.o -llttng-ust -ldl

构建流程

追踪应用

启动应用

./hello world and beyond

启动 session daemon

lttng-sessiond --daemonize

查看tracepoint

lttng list --userspace

创建会话

lttng create my-user-space-session

创建event规则

lttng enable-event --userspace hello_world:my_first_tracepoint

启动

lttng start

操作
输入enter，停止应用
停止追踪

lttng destroy

查看

babeltrace ~/lttng-traces/my-user-space-session*

效果

说明

对于构建我们需要安装devel包，这个通过efficios提供的yum包就包含了

参考资料

https://lttng.org/docs/v2.12/#doc-tracing-your-own-user-application

来源：oschina

链接：https://my.oschina.net/u/4284510/blog/4282755

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