VMSTAT(1) BSD Reference Manual VMSTAT(1) NNAAMMEE vmstat - report virtual memory statistics SSYYNNOOPPSSIISS vvmmssttaatt [[ --ffiimmsstt ]] [[ --cc ccoouunntt ]] [[ --MM ccoorree ]] [[ --NN ssyysstteemm ]] [[ --ww wwaaiitt ]] [[ ddiisskkss ]] DDEESSCCRRIIPPTTIIOONN _V_m_s_t_a_t reports certain kernel statistics kept about pro- cess, virtual memory, disk, trap and cpu activity. The options are as follows: -c Repeat the display _c_o_u_n_t times. The first display is for the time since a reboot and each subsequent report is for the time period since the last dis- play. If no _w_a_i_t interval is specified, the default is 1 second. -f Report on the number _f_o_r_k(2) and _v_f_o_r_k(2) system calls since system startup, and the number of pages of virtual memory involved in each. -i Report on the number of interrupts taken by each device since system startup. -M Extract values associated with the name list from the specified core instead of the default ``/dev/kmem''. -N Extract the name list from the specified system instead of the default ``/vmunix''. -m Report on the usage of kernel dynamic memory listed first by size of allocation and then by type of usage. -s Display the contents of the _s_u_m structure, giving the total number of several kinds of paging related events which have occurred since system startup. -t Report on the number of page in and page reclaims since system startup, and the amount of time required by each. -w Pause _w_a_i_t seconds between each display. If no repeat _c_o_u_n_t is specified, the default is infinity. By default, _v_m_s_t_a_t displays the following information: 4th Berkeley Distribution June 6, 1993 1 VMSTAT(1) BSD Reference Manual VMSTAT(1) procs Information about the numbers of processes in vari- ous 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 (reported in units of 1024 bytes) are considered active if they belong to pro- cesses which are running or have run in the last 20 seconds. 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) at pages attached (found in free list) pi pages paged in po pages paged out fr pages freed per second de anticipated short term memory shortfall sr pages scanned by clock algorithm, per-second disks Disk operations per second (this field is system dependent). Typically paging will be split across the available drives. The header of the field is the first character of the disk name and the unit number. If more than four disk drives are config- ured in the system, _v_m_s_t_a_t displays only the first four drives. To force _v_m_s_t_a_t to display specific drives, their names may be supplied on the command line. faults Trap/interrupt rate averages per second over last 5 seconds. in device interrupts per interval (including clock interrupts) sy system calls per interval cs cpu context switch rate (switches/interval) cpu Breakdown of percentage usage of CPU time. us user time for normal and low priority processes sy system time id cpu idle 4th Berkeley Distribution June 6, 1993 2 VMSTAT(1) BSD Reference Manual VMSTAT(1) EEXXAAMMPPLLEESS The command ``vmstat -i 5'' will print what the system is doing every five seconds; this is a good choice of print- ing interval since this is how often some of the statis- tics are sampled in the system. Others vary every second and running the output for a while will make it apparent which are recomputed every second. FFIILLEESS /vmunix default kernel namelist /dev/kmem default memory file SSEEEE AALLSSOO _f_s_t_a_t(1), _n_e_t_s_t_a_t(1), _n_f_s_s_t_a_t(1), _p_s(1), _s_y_s_t_a_t(1), _i_o_s_t_a_t(8), _p_s_t_a_t(8) The sections starting with ``Interpreting system activ- ity'' in _I_n_s_t_a_l_l_i_n_g _a_n_d _O_p_e_r_a_t_i_n_g _4_._3_B_S_D. BBUUGGSS The -c and -w options are only available with the default output. 4th Berkeley Distribution June 6, 1993 3