????Linux???????CPU??????????top?????????????????????top????????????????????????磺
????Mem:   4086496k total?? 4034428k used??    52068k free??   112620k buffers
????Swap: 4192956k total??   799952k used?? 3393004k free?? 1831700k cached
????top –M??????????M???λ
???????98.7%????????????ó??????????????????????
????PID USER      PR NI VIRT RES SHR S %CPU %MEM    TIME+ COMMAND
????25801 sybase    15   0 2648m 806m 805m S 1.0 20.2 27:56.96 dataserver
????12084 oracle    16   0 1294m 741m 719m S 0.0 18.6   0:13.50 oracle
????27576 xugy      25   0 986m 210m 1040 S 1.0 5.3 28:51.24 cti
????25587 yaoyang   17   0 1206m 162m 3792 S 0.0 4.1   9:21.14 java
??????%MEM???е?????????????????????????????????????????55%??????μ???涼?????????
?????????????Linux??????????????治?e?????????????????????е?????????????????????ó??????ж????????????
?????????top??????????????????????????buffers??cached????Linux???μ?buffer????????д???棬??cache??????????????檔
????(A buffer is something that has yet to be "written" to disk.
????A cache is something that has been "read" from the disk and stored for later use.)
??????????????????????Ч??????????棬????渻???????????????????????????????????????????????????????????湩??ó?????á?
????????????????ó????????????free+buffer+cache??????????????
????52068k + 112620k + 1831700k = 1996388k
?????????????????used-buffer-cache??????????????
????4034428k - 112620k - 1831700k = 2090108k
????Linux?2???滹????????????????free:
????$ free
????total       used       free     shared    buffers     cached
????Mem:       4086496    4034044      52452          0     112756    1831564
????-/+ buffers/cache:    2089724    1996772
????Swap:      4192956     799952    3393004
????Mem:????????top?????????????????????-/+buffers/cache???????????????????????used-buffer-cache/free+buffer+cache
??????????-m????-g????????MB????GB?????????
????$ free -m
????total       used       free     shared    buffers     cached
????Mem:          3990       3906         83          0         90       1786
????-/+ buffers/cache:       2029       1961
????Swap:         4094        781       3312
????????????????ó????????????????ó??????????????????????????51.1%??
???????磺
????# free -m
????total       used       free     shared    buffers     cached
????Mem:               4229       2834       1395          0         62       2548
????-/+ buffers/cache:                223        4006    //??????????223M?????4006M
????Swap:               8001       0         8001