vmstat

可用來紀錄 processes, memory, paging, block IO, traps, 與 cpu activity。

例如

$ vmstat 1 # 1 是更新速度，單位為秒
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy id wa
 1  0 549368  13316 102388  91992   12    6     9     8    2    12 72  3 25  0
 2  0 549368  13316 102388  91992    0    0     0     0  156  1516 98  2  0  0
 2  0 549368  13312 102388  91992    0    0     0     0  125   534 99  1  0  0
 
....

第一列與第二列所代表是執行程式的資訊，接下來的是記憶體、swap、io、systm 與 cpu。

   Procs
       r: The number of processes waiting for run time.
       b: The number of processes in uninterruptible sleep.
                                                                                
   Memory
       swpd: the amount of virtual memory used.
       free: the amount of idle memory.
       buff: the amount of memory used as buffers.
       cache: the amount of memory used as cache.
       inact: the amount of inactive memory. (-a option)
       active: the amount of active memory. (-a option)
                                                                                
   Swap
       si: Amount of memory swapped in from disk (/s).
       so: Amount of memory swapped to disk (/s).
  
   IO
       bi: Blocks received from a block device (blocks/s).
       bo: Blocks sent to a block device (blocks/s).
    System
       in: The number of interrupts per second, including the clock.
       cs: The number of context switches per second.
  
   CPU
       These are percentages of total CPU time.
       us: Time spent running non-kernel code. (user time, including nice time)
       sy: Time spent running kernel code. (system time)
       id: Time spent idle. Prior to Linux 2.5.41, this includes IO-wait time.
       wa: Time spent waiting for IO. Prior to Linux 2.5.41, shown as zero.