1,簡介
mpstat是Multiprocessor Statistics的縮寫，是實時系統監控工具。其報告是CPU的一些統計信息，這些信息存放在/proc/stat文件中。在多CPUs系統裡，其不但能查看所有CPU的平均狀況信息，而且能夠查看特定CPU的信息。mpstat最大的特點是：可以查看多核心cpu中每個計算核心的統計數據；而類似工具vmstat只能查看系統整體cpu情況。
2，安裝
[root@ora10g ~]# mpstat
-bash: mpstat: command not found
[root@ora10g ~]# mount -o loop -t iso9660 /dev/cdrom /mnt/cdrom
[root@ora10g ~]# cd /mnt/cdrom/Server/
[root@ora10g Server]# rpm -ivh sysstat-7.0.2-3.el5.i386.rpm
warning: sysstat-7.0.2-3.el5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
Preparing... ########################################### [100%]
1:sysstat ########################################### [100%]
3，實例
用法
mpstat -V 顯示mpstat版本信息
mpstat -P ALL 顯示所有CPU信息
mpstat -P n 顯示第n個cup信息，n為數字，計數從0開始
mpstat n m 每個n秒顯示一次cpu信息，連續顯示m次，最後顯示一個平均值
mpstat n 每個n秒顯示一次cpu信息，連續顯示下去
查看每個cpu核心的詳細當前運行狀況信息，輸出如下：
[root@ora10g ~]# mpstat -P ALL
Linux 2.6.18-194.el5 (ora10g.up.com) 11/05/14
09:13:02 CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s
09:13:02 all 0.62 0.01 0.54 3.48 0.00 0.02 0.00 95.32 1039.58
09:13:02 0 0.92 0.01 1.18 8.77 0.01 0.05 0.00 89.06 1030.23
09:13:02 1 0.27 0.00 0.31 1.46 0.00 0.01 0.00 97.96 1.00
....
09:13:02 14 1.12 0.02 0.45 2.99 0.00 0.01 0.00 95.39 7.74
09:13:02 15 0.18 0.00 0.22 0.70 0.00 0.01 0.00 98.90 0.59
查看多核CPU核心的當前運行狀況信息， 每2秒更新一次
[root@ora10g ~]# mpstat -P ALL 2
查看某個cpu的使用情況，數值在[0,cpu個數-1]中取值
[root@ora10g ~]# mpstat -P 2
Linux 2.6.18-194.el5 (ora10g.up.com) 11/05/14
10:19:28 CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s
10:19:28 2 0.08 0.00 0.04 0.22 0.00 0.01 0.00 99.64 0.55
查看多核CPU核心的當前運行狀況信息， 每2秒更新一次，顯示5次
[root@ora10g ~]# mpstat -P ALL 2 5
4,字段含義如下
英文解釋：
CPU：Processor number. The keyword all indicates that statistics are calculated as averages among all processors.
%user：Show the percentage of CPU utilization that occurred while executing at the user level (application).
%nice：Show the percentage of CPU utilization that occurred while executing at the user level with nice priority.
%sys：Show the percentage of CPU utilization that occurred while executing at the system level (kernel). Note that
this does not include time spent servicing interrupts or softirqs.
%iowait：Show the percentage of time that the CPU or CPUs were idle during which the system had an outstanding disk I/O request.
%irq：Show the percentage of time spent by the CPU or CPUs to service interrupts.
%soft：Show the percentage of time spent by the CPU or CPUs to service softirqs. A softirq (software interrupt) is
one of up to 32 enumerated software interrupts which can run on multiple CPUs at once.
%steal：Show the percentage of time spent in involuntary wait by the virtual CPU or CPUs while the hypervisor was ser-vicing another virtual processor.
%idle：Show the percentage of time that the CPU or CPUs were idle and the system did not have an outstanding disk I/O request.
intr/s：Show the total number of interrupts received per second by the CPU or CPUs.
參數解釋 從/proc/stat獲得數據
CPU 處理器 ID
user 在internal時間段裡，用戶態的CPU時間（%），不包含 nice值為負 進程 (usr/total)*100
nice 在internal時間段裡，nice值為負進程的CPU時間（%） (nice/total)*100
system 在internal時間段裡，核心時間（%） (system/total)*100
iowait 在internal時間段裡，硬盤IO等待時間（%） (iowait/total)*100
irq 在internal時間段裡，硬中斷時間（%） (irq/total)*100
soft 在internal時間段裡，軟中斷時間（%） (softirq/total)*100
idle 在internal時間段裡，CPU除去等待磁盤IO操作外的因為任何原因而空閒的時間閒置時間（%）(idle/total)*100
intr/s 在internal時間段裡，每秒CPU接收的中斷的次數intr/total)*100
CPU總的工作時間=total_cur=user+system+nice+idle+iowait+irq+softirq
total_pre=pre_user+ pre_system+ pre_nice+ pre_idle+ pre_iowait+ pre_irq+ pre_softirq
user=user_cur – user_pre
total=total_cur-total_pre
其中_cur 表示當前值，_pre表示interval時間前的值。上表中的所有值可取到兩位小數點。
