内存子系统调优

内存子系统

虚拟内存

swap

内存页(page)

page in , page out <--- paging(内存分页)

# free -m

total used free shared buffers cached

Mem: 2017 1963 54 0 6 1573

-/+ buffers/cache: 383 1634

Swap: 4094 0 4094

# vmstat 2 2

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------

r b swpd free buff cache si so bi bo in cs us sy id wa st

1 0 116 54912 7288 1612464 0 0 409 15 1128 1339 13 8 78 1 0

0 0 116 54912 7288 1612468 0 0 0 0 2493 3202 15 9 76 0 0

-----------memory---------- ---swap--

swpd free buff cache si so

116 54912 7288 1612464 0 0

116 54912 7288 1612468 0 0

si 从swap分区读取到内存

so 把内存中的数据写到swap

bi 从块设备读取数据到内存

bo 把内存上数据写回硬盘

slabtop

查看主页面故障，次页面故障

# /usr/bin/time -v date

...

/usr/bin/time -v date

Wed Jul 31 14:04:28 CST 2013

Command being timed: "date"

User time (seconds): 0.00

System time (seconds): 0.00

Percent of CPU this job got: 0%

Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.00

Average shared text size (kbytes): 0

Average unshared data size (kbytes): 0

Average stack size (kbytes): 0

Average total size (kbytes): 0

Maximum resident set size (kbytes): 3248

Average resident set size (kbytes): 0

Major (requiring I/O) page faults: 0 主页面故障

Minor (reclaiming a frame) page faults: 254 次页面故障

Voluntary context switches: 2

Involuntary context switches: 0

Swaps: 0

File system inputs: 0

File system outputs: 0

Socket messages sent: 0

Socket messages received: 0

Signals delivered: 0

Page size (bytes): 4096

Exit status: 0

主页面故障： 当程序执行的时候，如果需要数据在内存中没有，就会产生主页面故障

次页面故障： 当程序执行的时候，需要的数据直接在内存中得到，就会产生页面故障

内核调度和自身调优：就是不断减少主页面故障，增加次页面故障

查看内存分页情况

# yum install procinfo -y （安装软件）

# procinfo -n3

Memory: Total Used Free Shared Buffers Cached

Mem: 4184576 4143876 40700 0 1020948 2819268

Swap: 12586888 25744 12561144

Bootup: Tue Jun 4 17:38:06 2013 Load average: 0.02 0.01 0.00 1/250 24424

user : 2:49:55.58 0.1% page in : 151801646 disk 1: 2411948r27929765w

nice : 0:00:20.37 0.0% page out: 1164277021 disk 2: 271r 0w

system: 1:44:12.85 0.0% page act: 28374089 disk 3: 250r 0w

IOwait: 1d 6:41:46.08 1.1% page dea: 2610283

hw irq: 0:00:00.00 0.0% page flt: 184984723

sw irq: 0:23:00.97 0.0% swap in : 4261

idle : 111d 22:24:14.12 98.4% swap out: 30399

steal : 6:56:39.11 0.2%

uptime: 56d 20:24:57.55 context : 3295431496

irq 1: 2 i8042 irq823: 8366639 eth5-0

irq 4: 11 serial irq832:1001656270 timer

irq 8: 2 rtc0 irq833: 57010471 ipi

irq 9: 0 acpi irq834: 0 pcpu

irq 12: 4 i8042 irq835: 0 mce

irq 18: 0 uhci_hcd:usb4 irq836: 0 console

irq 19: 67 ata_piix, ata_piix, u irq837: 343466 xenbus [0] [1] [2 [7]

irq 23: 2 ehci_hcd:usb1, uhci_h irq838: 0 suspend

irq 24: 1623853 lpfc irq839: 5462043 blkif-backend

irq 32: 23733230 ioc0 irq840: 43 blkif-backend

irq 34: 1868961 lpfc irq841: 62621924 vif7.0

irq794: 0 eth4-2 irq842: 477069 blkif-backend

irq795: 0 eth4-1 irq843: 330846 blkif-backend

irq796: 1 eth4-0 irq844: 4255098 vif9.0

irq803: 3477198 eth2-2 irq845: 28702 blkif-backend

irq804: 4151377 eth2-1 irq846: 31 blkif-backend

irq805: 575565975 eth2-0 irq847: 663201 vif10.0

irq812: 0 eth6-2 irq848: 30686 blkif-backend

irq813: 0 eth6-1 irq849: 31 blkif-backend

irq814: 1 eth6-0 irq850: 243862 vif11.0

irq821: 55483005 eth5-2 irq851: 2875247 vif24.0

irq822: 43854772 eth5-1

查看当前主、次页面故障情况

# sar -B 2 3

17时48分17秒 pgpgin/s pgpgout/s fault/s majflt/s

17时48分19秒 0.00 0.00 22.77 0.00

17时48分21秒 0.00 0.00 11.88 0.00

17时48分23秒 0.00 15.92 6.47 0.00

Average: 0.00 5.29 13.72 0.00