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How to use DTrace and mdb to Interpret vmstat Statistics (Doc ID 1009494.1)

Last updated on MARCH 21, 2018

Applies to:

Solaris Operating System - Version 10 3/05 and later
All Platforms

Goal

Vmstat reports system-wide physical and virtual memory (swap) usage and CPU utilization.  Vmstat statistics can be used to estimate:

The purpose of this document is to interpret vmstat statistics and demonstrate how advanced tools like DTrace and mdb can be used to drill down into vmstat statistics for evaluating overall system performance.

It's preferable to have the DTraceToolkit on the target system. It contains a collection of over 200 useful and documented DTrace scripts developed by Brendan Gregg.


Sample output:

$ vmstat 5
kthr   memory        page           disk       faults    cpu
r b w swap free re mf pi po fr de sr m0 m1 m2 m3 in sy cs us sy id
0 0 0 19418464 9493440 40 262 159 3 4 0 41 3 0 74 0 7946 169573 10669 9 3 88
0 0 0 10991520 8688968 230 2340 0 22 20 0 0 5 0 115 0 13726 25882 15384 6 5 89
0 0 0 10987336 8684128 108 601 0 1 1 0 0 0 0 116 0 14413 25732 16704 6 5 90
0 0 0 10977816 8678864 49 380 0 0 0 0 0 10 0 105 0 14369 26459 16552 6 5 90
0 0 0 10984696 8681064 5 42 0 0 0 0 0 0 0 119 0 14971 24379 16879 5 5 90
0 0 0 10823352 8527936 35 235 0 0 0 0 0 6 0 113 0 18699 32770 24136 7 6 87
0 0 0 10700096 8408408 21 159 0 0 0 0 0 2 0 117 0 25726 37776 37806 8 8 84
0 0 0 10703552 8410768 12 73 0 8 8 0 0 1 0 116 0 22349 36270 30961 8 7 85
0 0 0 10695072 8402112 3 53 0 0 0 0 0 3 0 111 0 29727 33655 45830 7 9 84

Solution

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In this Document
Goal
Solution
 kthr: Runnable Threads (r)
 kthr: Block Threads (b)
 kthr: Swapped out Threads (w)
 memory: Available virtual swap (swap)
 memory: Available physical memory (free)
 page: Pages reclaimed (re)
 page: Minor faults (mf)
 page: Kilobytes paged in (pi)
 page: Kilobytes paged out (po)
 page: Kilobytes freed by page scanner (fr)
 page: Anticipated memory shortfall (de)
 page: Number of Pages scanned by page scanner (sr)
 disk: disk operation per second (m0,1,2,3)
 faults: Number of interrupts serviced by CPUs (in)
 faults: Number of system calls issued (sy)
 faults: Context switching activity (cs)
 cpu: user or application CPU time (us)
 cpu: Kernel CPU usage (sy)
 cpu: CPU idle  (id)
References

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