3 iostats \- file system to measure I/O
19 is a user-level file server that interposes itself between a program
20 and the regular file server, which
21 allows it to gather statistics of file system
22 use at the level of the Plan 9 file system protocol, 9P.
24 exits a report is printed on standard error.
26 The report consists of three sections.
27 The first section reports the amount
32 messages sent by the program and the average rate at
33 which the data was transferred.
36 line reports the amount
37 of data sent as message headers, that is,
42 total number of file system transactions.
44 The second section gives
45 the number of messages, the fastest, slowest, and average turn around
46 time and the amount of data involved with each 9P
48 The final section gives an I/O summary for each file used
49 by the program in terms of opens, reads and writes.
53 flag is present, a debugging log including all traffic
59 Display summary of file I/O incurred by
66 Start a new shell, displaying all 9P traffic caused by the shell or its children:
72 .B /sys/src/cmd/iostats
76 Poor clock resolution means that large amounts of I/O must be done to
77 get accurate rate figures.
79 Can be fooled by programs that do fresh mounts outside its purview,
80 or by the use of names of files with content that can vary by process (e.g.,