nfsdist - Summarize NFS operation latency. Uses Linux eBPF/bcc.

       Samuel Nair

       This  tool  summarizes  time  (latency)  spent  in  common NFS file operations: reads, writes, opens, and
       getattrs, and presents it as a power-of-2 histogram. It uses an in-kernel eBPF map to store the histogram
       for efficiency.

       Since this works by tracing the nfs_file_operations interface functions, it will need updating  to  match
       any changes to these functions.

       Since this uses BPF, only the root user can use this tool.

       Trace NFS operation time, and print a summary on Ctrl-C:
              # nfsdist

       Trace PID 181 only:
              # nfsdist-p181

       Print 1 second summaries, 10 times:
              # nfsdist110

       1 second summaries, printed in milliseconds
              # nfsdist-m1

       msecs  Range of milliseconds for this bucket.

       usecs  Range of microseconds for this bucket.

       count  Number of operations in this time range.

       distribution
              ASCII representation of the distribution (the count column).

       nfsdist - Summarize NFS operation latency. Uses Linux eBPF/bcc.

       -h     Print usage message.

       -T     Don't include timestamps on interval output.

       -m     Output in milliseconds.

       -p PID Trace this PID only.

       Linux

       This  adds low-overhead instrumentation to these NFS operations, including reads and writes from the file
       system cache. Such reads and writes can be very frequent (depending on  the  workload;  eg,  1M/sec),  at
       which point the overhead of this tool may become noticeable.  Measure and quantify before use.

       CONFIG_BPF and bcc.

nfsslower(8)

USER COMMANDS                                      2017-09-08                                         nfsdist(8)

       This is from bcc.

              https://github.com/iovisor/bcc

       Also  look  in  the bcc distribution for a companion _examples.txt file containing example usage, output,
       and commentary for this tool.

       Unstable - in development.

nfsdist[-h][-T][-m][-pPID][interval][count]