Linux 轮询系统调用超时
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poll system call timeout
提问by mahmood
Attaching straceshows a lot of these messages:
附件strace显示了很多这样的消息：
poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}], 6, 0) = 0 (Timeout)
poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}], 6, 0) = 0 (Timeout)
poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}], 6, 0) = 0 (Timeout)
poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}], 6, 0) = 0 (Timeout)
How can I find what file the program is trying to access that causes pollsystem call to timeout?
如何找到程序试图访问导致poll系统调用超时的文件？
stracegenerates a lot of messages which make it hard to debug
strace生成大量消息，使调试变得困难
回答by Maxim Egorushkin
How can I find what file the program is trying to access that causes poll system call to timeout?
如何找到程序试图访问导致轮询系统调用超时的文件？
Invoke:
调用：
lsof -p <pid>
And see what the file descriptors in question refer to.
并查看有问题的文件描述符指的是什么。
You can also take a look into procfilesystem on Linux:
您还可以查看procLinux 上的文件系统：
ls -l /proc/<pid>/fd
回答by Kamel Haddad
ls -l /proc//fd/ -> You will get the corresponding node Id. ss -p | grep -> you will get the socket file path the fd belongs to.
ls -l /proc//fd/ -> 你会得到对应的节点Id。ss -p | grep -> 您将获得 fd 所属的套接字文件路径。
