VMSTAT(1) UNIX Programmer's Manual VMSTAT(1) NAME vmstat - report virtual memory statistics SYNOPSIS vmstat [ -fs ] [ -i ] [ interval [ count ] ] DESCRIPTION _V_m_s_t_a_t delves into the system and normally reports certain statistics kept about process, virtual memory, disk, trap and cpu activity. If given a -f argument, it instead reports on the number of _f_o_r_k_s and _v_f_o_r_k_s since system startup and the number of pages of virtual memory involved in each kind of fork. If given a -s argument, it instead prints the contents of the _s_u_m structure, giving the total number of several kinds of paging related events which have occurred since boot. If none of these options are given, _v_m_s_t_a_t will report in a (usually) iterative fashion on the virtual memory activity in the system. In this case, the optional _i_n_t_e_r_v_a_l argument causes _v_m_s_t_a_t to report once each _i_n_t_e_r_v_a_l seconds; ``vmstat 5'' will print what the system is doing every five seconds; this is a good choice of printing interval since this is how often the statistics are sampled in the system. If a _c_o_u_n_t is given, the statistics are repeated _c_o_u_n_t times. There are two formats; fields for the older format which is forced by the -i option are tersely described later. The default format fields are: Procs: information about numbers of processes in various states. R in run queue B blocked for resources (i/o, paging, etc.) W runnable or short sleeper (< 20 secs) but swapped Memory: information about the usage of virtual and real memory. Virtual pages are considered active if they belong to processes which are running or have run in the last 20 seconds. A ``page'' here is 1024 bytes. AVM active virtual pages FRE size of the free list Page: information about page faults and paging activity. These are averaged each five seconds, and given in units per second. RE page reclaims (simulating reference bits) PI page-in events PO page-out events FR pages freed per second Printed 11/10/80 4/22/80 1 VMSTAT(1) UNIX Programmer's Manual VMSTAT(1) DE anticipated short term memory shortfall SR scan rate: pageout daemon rpm Swap: information about the activity of the swap daemon (process 0). I process swap ins in last 5 seconds O process swap outs in last 5 seconds Disk: operations per second (this field is system depen- dent). Typically paging will be split across several of the available drives. D0 disk 0; on csvax: /usr file system D1 disk 1; on csvax: on csvax: /va, /tmp and some paging D2 disk 2; on csvax: /, /vb, /3bsd, /3bsd/usr and some paging D3 disk 3; on csvax: /arch, /4bsd, /4bsd/usr and some paging Faults: trap/interrupt rate averages per second over last 5 seconds. IN (non clock) device interrupts per second SY system calls per second PD pseudo-dma interrupts on DZ CS cpu context switch rate (switches/sec) Cpu: breakdown of percentage usage of CPU time US user time for normal and low priority processes SY system time ID cpu idle For the older format, process states are broken down into RU (runnable), DW (disk i/o wait), PW (page wait), SL (sleeping in core), and SW (swapped out while recently active). For memory usage, the percentage of memory used by sharable pages is printed as TX. Fault information is not printed, but the percentage of CPU time given to low priority jobs is given as NI. FILES /dev/kmem, /vmunix SEE ALSO The sections starting with ``Interpreting system activity'' in _S_e_t_t_i_n_g _u_p _t_h_e _F_o_u_r_t_h _B_e_r_k_e_l_e_y _S_o_f_t_w_a_r_e _T_a_p_e by W. Joy, O. Babaoglu, and K. Sklower AUTHORS William Joy and Ozalp Babaoglu Printed 11/10/80 4/22/80 2 VMSTAT(1) UNIX Programmer's Manual VMSTAT(1) BUGS Printed 11/10/80 4/22/80 3