Linux:perf top，找不到内核符号

Question

Ubuntu 15.04，已编译安装 Linux-Next 内核 2015-06-04。

然后启动这个内核，然后运行 ​​perf top，但它说找不到符号。

如何在 perf 中手动加载内核符号？

root@ubuntu-server:/boot# uname -r
4.1.0-rc6.060402222+

root@ubuntu-server:/proc# ls kall*
kallsyms

root@ubuntu-server:/boot# ls | grep 4.1.0-rc6.060402222
config-4.1.0-rc6.060402222+
initrd.img-4.1.0-rc6.060402222+
System.map-4.1.0-rc6.060402222+
vmlinuz-4.1.0-rc6.060402222+

root@ubuntu-server:/# perf top
No kallsyms or vmlinux with build-id 438e4365574d514672888bcfdd6292dbcf71f38f was found
[kernel.kallsyms] with build id 438e4365574d514672888bcfdd6292dbcf71f38f not found, continuing without symbols
Warning:
A vmlinux file was not found.
Kernel samples will not be resolved.
^C

root@ubuntu-server:/proc# perf top -k /boot/vmlinuz-4.1.0-rc6.060402222+
Warning:
The /boot/vmlinuz-4.1.0-rc6.060402222+ file can't be used: Success
Kernel samples will not be resolved.
^C

在 Linux-next 文件夹中，.config 文件已启用内核调试:

CONFIG_DEBUG_KERNEL=y

Answer 1

我安装了 perf，并运行“perf top”，得到以下消息:

Warning:

A vmlinux file was not found.

Kernel samples will not be resolved.

安装“libelf-dev”后，我再次编译perf并进行安装。最后，我运行“perf top”并得到正确的结果。

在安装perf的过程中，系统会给出一些提示。例如:

config/Makefile:276: No libelf found, disables 'probe' tool, please install elfutils-libelf-devel/libelf-dev

config/Makefile:327: No libunwind found, disabling post unwind support. Please install libunwind-dev[el] >= 1.1

config/Makefile:350: No libaudit.h found, disables 'trace' tool, please install audit-libs-devel or libaudit-dev

config/Makefile:364: slang not found, disables TUI support. Please install slang-devel or libslang-dev

按照这些提示，也许您可​​以解决您的问题。