开始学习cuda编程了，就会遇到好多的问题，怎么知道是哪里出问题了呢，CUDA自带的cuda-gdb就会帮到我们啦。NVIDA对开源的GUN调试器进行了扩展，CUDA-GDB包含以下功能：
- 观察CUDA状态，例如已安装的GPU及其支持的功能
- 在CUDA C中设置断点
- 分享GPU中内存，包括全局内存和共享内存
- 单步调试
- 分析当前驻留在GPU上的线程块和线程
- 设置断点调试
首先输入cuda-gdb就会进入这样的模式
server@Server-1:~/xtk/Exercises/Test1$ cuda-gdb
NVIDIA (R) CUDA Debugger
8.0 release
Portions Copyright (C) 2007-2016 NVIDIA Corporation
GNU gdb (GDB) 7.6.2
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
(cuda-gdb)(cuda-gdb) set cuda software_preemption on
(cuda-gdb) file a.out
Reading symbols from /home/dutoeserver/xtk/Exercises/Test1/a.out...done.
(cuda-gdb) b 2
Breakpoint 1 at 0x402bf2: file myFirstKernel.cu, line 2.
(cuda-gdb) r调试方法
在gdb中所有不冲突的指令都可以输入简写，即第一个首字母
1.允许在图形界面模式下进行调试。
set cuda software-preemption on
2.指定要调试的.out文件 file a.out
3.b 20 从20行设置断点 b 作为break的简写
4.r 运行
5.n 继续执行下一步 next 5 往后执行5行
6.p result 输出result变量的值 printf
7.quit 退出调试
