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Posts in DTrace
Viewing NFS client operations
While reading through the NFS RFCs this week, I decided to write nfsclientstats .pl to view NFS operations by process: The script uses the DTrace FBT provider, and produces output that is greater than 80-characters. If you are an 80-column purist, you might want to refrain from downloading the script. ;) Hope folks find this useful!
$ read more →Gathering file and directory statistics with DTrace
After learning about fsstat, I decided to create a similar program that used DTrace (fsstat uses libkstat). After reading through syscall.h and reviewing the system calls available in the syscall provider, I created dfs stat.pl: Hope folks find this useful.
$ read more →Debugging DTrace
While catching up on the DTrace discussion list tonight, I came across a cool DTrace debugging recommendation from Adam Leventhal. Adam mentioned using the DTRACE_DEBUG flag, which will cause libdtrace to spew tons of debugging data each time dtrace is invoked: This is super cool, and useful for tracking down problems, or learning more about what DTrace does behind the scenes.
$ read more →Jarod Jenson coming to Atlanta to talk about DTrace
If you live in the Atlanta, GA area, you might be interested to know that Jarod Jenson will be talking about DTrace April 19th at the Marriott Perimeter Center. The event is being put on by Sun FREE of charge, and will be way better than any training course you could take on the subject ( there is one exception; a class by Brendan Gregg would be just as awesome )! Sun is requiring pre-registration to ensure that enough seats are available, and the meeting will be held at a swank location! I plan to wander to the event with Clay, and I am hoping to learn more about DTrace, the DVM provider, debugging and DTrace implementation details…
$ read more →Viewing system call errors with DTrace
When an application needs to access one of the services provided by the kernel, the application typically invokes a system call. When a system call returns, the system call will typically provide a return value to indicate success or failure, and in the case of a failure, the global errno variable will be set to indicate the specific error that occurred. To see what errors are occurring on a system or within a specific process, the DTraceToolkit's errinfo script can be used: This will print the system calls that returned with an error condition, the value of the errno, and the error number description from errno.h. This is a super useful script, and can make tracking down errors super easy.
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