From 8828467a1b3a2ad4bcdfbc578cf00e956914ec23 Mon Sep 17 00:00:00 2001
From: gatieme <gatieme@163.com>
Date: Fri, 31 Mar 2017 14:14:03 +0800
Subject: [PATCH] debug...

---
 study/debug/README.md                | 18 +++++++++--
 study/debug/modules/printk/README.md | 46 ++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 3 deletions(-)
 create mode 100644 study/debug/modules/printk/README.md

diff --git a/study/debug/README.md b/study/debug/README.md
index 9add5a7..59fa8b6 100644
--- a/study/debug/README.md
+++ b/study/debug/README.md
@@ -196,6 +196,18 @@ mount -t sysfs sysfs /sysfs
 #3  printk
 -------
 
+在内核调试技术之中, 最简单的就是 `printk` 的使用了, 它的用法和C语言应用程序中的 `printf` 使用类似, 在应用程序中依靠的是 `stdio.h` 中的库, 而在 `linux` 内核中没有这个库, 所以在 `linux` 内核中, 实现了自己的一套库函数, `printk` 就是标准的输出函数
+
+
+[linux内核调试技术之printk](http://www.cnblogs.com/veryStrong/p/6218383.html)
+
+
+[调整内核printk的打印级别](http://blog.csdn.net/tonywgx/article/details/17504001)
+
+
+[ linux设备驱动学习笔记--内核调试方法之printk](http://blog.csdn.net/itsenlin/article/details/43205983)
+
+
 
 #4	ftrace && trace-cmd
 -------
@@ -255,7 +267,7 @@ mount -t sysfs sysfs /sysfs
 
 
 
-##4.2   trace-cmd
+##4.2   ftrace前端工具trace-cmd
 -------
 
 *	trace-cmd 介绍
@@ -284,7 +296,7 @@ sudo trace-cmd reord subsystem:tracing
 #5	Kprobe && systemtap
 -------
 
-##5.1   kprobe
+##5.1   内核kprobe机制
 -------
 
 
@@ -312,7 +324,7 @@ sudo trace-cmd reord subsystem:tracing
 
 
 
-##5.2   systemtap
+##5.2   前端工具systemtap
 -------
 
 
diff --git a/study/debug/modules/printk/README.md b/study/debug/modules/printk/README.md
new file mode 100644
index 0000000..0d07028
--- /dev/null
+++ b/study/debug/modules/printk/README.md
@@ -0,0 +1,46 @@
+http://blog.csdn.net/arethe/article/details/6293505]
+http://lxr.free-electrons.com/source/Documentation/trace/tracepoints.txt
+https://lwn.net/Articles/410200/
+
+
+#1  驱动安装
+-------
+
+
+sudo insmod trace-events-sample.ko
+
+
+#2  检查驱动
+-------
+
+cat /sys/kernel/debug/tracing/available_events | grep sample-trace
+
+cd /sys/kernel/debug/tracing/events/sample-trace
+
+
+#3  列出所有的events
+-------
+
+find /sys/kernel/debug/tracing/events -type d
+
+cat /sys/kernel/debug/tracing/available_events
+
+trace-cmd list
+
+perf list 2>&1 | grep Tracepoint
+
+#3  trace-cmd
+-------
+
+sudo trace-cmd reset
+
+sudo trace-cmd record -e sample-trace:foo_with_template_print
+
+sudo trace-cmd report
+
+
+#文档中的错误
+-------
+
+http://lxr.free-electrons.com/source/Documentation/trace/events.txt?v=4.10#L278
+all events but those that have not a prev_pid field retain their old filters