ICode9

精准搜索请尝试: 精确搜索
首页 > 编程语言> 文章详细

《内核kernel:示踪标志 trace marker 调试程序编写》

2019-09-02 14:43:28  阅读:1411  来源: 互联网

标签:count kernel rlk trace ... tracing mark write 调试程序


需求: 使用 trace_marker 来跟踪程序

trace_marker 是一个文件节点,允许用户程序写入字符串,frace 会记录写入动作的时间戳

cd /sys/kernel/debug/tracing/

echo nop > current_tracer // 设置function 跟踪器是不能捕捉到示踪标志
echo 1 > tracing_on // 打开ftrace 才能捕捉到示踪标志

echo 0 > tracing_on // 关闭ftrace

 

一、程序编写

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/time.h>
#include <linux/unistd.h>
#include <stdarg.h>
#include <unistd.h>
#include <ctype.h>

static int mark_fd = -1;
static __thread char buff[BUFSIZ+1];

static void setup_ftrace_marker(void)
{
	struct stat st;
	char *files[] = {
		"/sys/kernel/debug/tracing/trace_marker",
		"/debug/tracing/trace_marker",
		"/debugfs/tracing/trace_marker",
	};
	int ret;
	int i;

	for (i = 0; i < (sizeof(files) / sizeof(char *)); i++) {
		ret = stat(files[i], &st);
		if (ret >= 0)
			goto found;
	}
	/* todo, check mounts system */
	printf("canot found the sys tracing\n");
	return;
found:
	mark_fd = open(files[i], O_WRONLY);
}

static void ftrace_write(const char *fmt, ...)
{
	va_list ap;
	int n;

	if (mark_fd < 0)
		return;

	va_start(ap, fmt);
	n = vsnprintf(buff, BUFSIZ, fmt, ap);
	va_end(ap);

	write(mark_fd, buff, n);
}

int main()
{
	int count = 0;
	setup_ftrace_marker();
	ftrace_write("rlk start program\n");
	while (1) {
		usleep(100*1000);
		count++;
		ftrace_write("rlk count=%d\n", count);
	}
}

编译: arm-linux-gnueabi-gcc trace_marker_test.c -o trace_marker_test --static

运行:

/sys/kernel/debug/tracing # /mnt/trace_marker_test 

... 等待几秒
Ctrl+c 终止程序

/sys/kernel/debug/tracing # cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 170/170   #P:4
#
#                              _-----=> irqs-off
#                             / _----=> need-resched
#                            | / _---=> hardirq/softirq
#                            || / _--=> preempt-depth
#                            ||| /     delay
#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
#              | |       |   ||||       |         |
           <...>-778   [000] ...1   124.054672: tracing_mark_write: rlk start program
           <...>-778   [000] ...1   124.180858: tracing_mark_write: rlk count=1
           <...>-778   [000] ...1   124.297803: tracing_mark_write: rlk count=2
           <...>-778   [000] ...1   124.408593: tracing_mark_write: rlk count=3
           <...>-778   [000] ...1   124.518589: tracing_mark_write: rlk count=4
           <...>-778   [000] ...1   124.628374: tracing_mark_write: rlk count=5
           <...>-778   [000] ...1   124.738971: tracing_mark_write: rlk count=6
           <...>-778   [000] ...1   124.849366: tracing_mark_write: rlk count=7
           <...>-778   [000] ...1   124.959502: tracing_mark_write: rlk count=8
           <...>-778   [000] ...1   125.071421: tracing_mark_write: rlk count=9
           <...>-778   [000] ...1   125.190520: tracing_mark_write: rlk count=10
           <...>-778   [000] ...1   125.300335: tracing_mark_write: rlk count=11
           <...>-778   [000] ...1   125.401471: tracing_mark_write: rlk count=12
           <...>-778   [000] ...1   125.511686: tracing_mark_write: rlk count=13
           <...>-778   [000] ...1   125.621551: tracing_mark_write: rlk count=14
           <...>-778   [000] ...1   125.732367: tracing_mark_write: rlk count=15
           <...>-778   [000] ...1   125.842521: tracing_mark_write: rlk count=16
           <...>-778   [000] ...1   125.952524: tracing_mark_write: rlk count=17
           <...>-778   [000] ...1   126.063389: tracing_mark_write: rlk count=18
           <...>-778   [000] ...1   126.173682: tracing_mark_write: rlk count=19

 

标签:count,kernel,rlk,trace,...,tracing,mark,write,调试程序
来源: https://blog.csdn.net/yexiangCSDN/article/details/97892316

本站声明: 1. iCode9 技术分享网(下文简称本站)提供的所有内容,仅供技术学习、探讨和分享;
2. 关于本站的所有留言、评论、转载及引用,纯属内容发起人的个人观点,与本站观点和立场无关;
3. 关于本站的所有言论和文字,纯属内容发起人的个人观点,与本站观点和立场无关;
4. 本站文章均是网友提供,不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属;如您发现该文章侵犯了您的权益,可联系我们第一时间进行删除;
5. 本站为非盈利性的个人网站,所有内容不会用来进行牟利,也不会利用任何形式的广告来间接获益,纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。

专注分享技术,共同学习,共同进步。侵权联系[81616952@qq.com]

Copyright (C)ICode9.com, All Rights Reserved.

ICode9版权所有