c 语言使用lttng
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
