這是一篇關於Linux內存measuring的基礎教程。除了free之外,我們可以通過/proc得到更多信息。它們是/proc下的maps,smaps 和statm。
'free' and /proc
'free' 會顯示機器上的內存使用信息。能實時跟蹤整個系統內存的使用情況。
$ free
total used free shared buffers cached
Mem: 507564 481560 26004 0 68888 185220
-/+ buffers/cache: 227452 280112
Swap: 2136604 105168 2031436
除了free命令之外,/proc/meminfo能夠提供更多的信息。以下就是一個例子: 512 Mb RAM, 運行在 Linux 2.6.3:
$ cat /proc/meminfo
MemTotal: 507564 kB
MemFree: 26004 kB
Buffers: 68888 kB
Cached: 185220 kB
SwapCached: 29348 kB
Active: 342488 kB
Inactive: 32092 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 507564 kB
LowFree: 26004 kB
SwapTotal: 2136604 kB
SwapFree: 2031436 kB
Dirty: 88 kB
Writeback: 0 kB
Mapped: 165648 kB
Slab: 73212 kB
Committed_AS: 343172 kB
PageTables: 2644 kB
VmallocTotal: 524212 kB
VmallocUsed: 7692 kB
VmallocChunk: 516328 kB
測量用戶進程的內存使用:
'ps' 能夠提供內存信息情況。比如:
PID RSS VSZ COMMAND
3129 23100 213664 GAM
· %Mem - 內存使用百分比
· VSZ - Virtual Size
· RSS - Resident Set Size
· SIZE - Equivalent to VSZ
· %MEM -- Memory usage (RES) 進程當前使用的物理內存。
· VIRT -- Virtual Image (kb) 進程整個virtual memory空間, VIRT = SWAP + RES
· SWAP -- Swapped size (kb) virtual memory交換到disk或者沒有加載到物理內存裡的空間。
· RES -- Resident size (kb) 進程駐留在內存裡面的內存大小, RES = CODE + DATA.
· CODE -- Code size (kb) 加載到內存裡面的可執行文件代碼
· DATA -- Data+Stack size (kb) 加載到內存裡面的數據和棧
· SHR -- Shared Mem size (kb) 共享內存大小
· nDRT -- Dirty Pages count 頁面已經修改但是還沒有保存到disk的數目。
更多信息可以使用命令:'man proc'
/proc/<pid>/statm fields: columns are (in pages):
total program size|
resident set size|
shared pages|
text (code) |
data/stack |
library |
dirty pages |
Here an example: 693 406 586 158 0 535 0
/proc/<pid>/status fields:
· Vm Size: 2772 kB
· Vm Lck: 0 kB - ???
· Vm RSS: 1624 kB
· Vm Data: 404 kB
· Vm Stk: 24 kB
· Vm Exe: 608 kB
· Vm Lib: 1440 kB
maps顯示所有共享庫映射到進程地址空間的詳細情況。Example:
$ cat /proc/25042/maps
08048000-080e0000 r-xp 00000000 03:05 196610 /bin/bash
080e0000-080e6000 rw-p 00097000 03:05 196610 /bin/bash
080e6000-08148000 rwxp 00000000 00:00 0
40000000-40016000 r-xp 00000000 03:05 147471 /lib/ld-2.3.3.so
40016000-40017000 rw-p 00015000 03:05 147471 /lib/ld-2.3.3.so
40017000-40018000 rw-p 00000000 00:00 0
40018000-40019000 r--p 00000000 03:05 184090 /usr/share/locale/en_US/LC_IDENTIFICATION
40019000-4001a000 r--p 00000000 03:05 184089 /usr/share/locale/en_US/LC_MEASUREMENT
4001a000-4001b000 r--p 00000000 03:05 184083 /usr/share/locale/en_US/LC_TELEPHONE
4001b000-4001c000 r--p 00000000 03:05 184091 /usr/share/locale/en_US/LC_ADDRESS
4001c000-4001d000 r--p 00000000 03:05 184086 /usr/share/locale/en_US/LC_NAME
4001d000-4001e000 r--p 00000000 03:05 184084 /usr/share/locale/en_US/LC_PAPER
4001e000-4001f000 r--p 00000000 03:05 184088 /usr/share/locale/en_US/LC_MESSAGES/SYS_LC_MESSAGES
4001f000-40020000 r--p 00000000 03:05 184087 /usr/share/locale/en_US/LC_MONETARY
40020000-40026000 r--p 00000000 03:05 183689 /usr/share/locale/ISO-8859-1/LC_COLLATE
40026000-40027000 r--p 00000000 03:05 184082 /usr/share/locale/en_US/LC_TIME
40027000-4002a000 r-xp 00000000 03:05 147459 /lib/libtermcap.so.2.0.8
4002a000-4002b000 rw-p 00002000 03:05 147459 /lib/libtermcap.so.2.0.8
4002b000-4002c000 rw-p 00000000 00:00 0
4002c000-4002e000 r-xp 00000000 03:05 147482 /lib/libdl-2.3.3.so
4002e000-4002f000 rw-p 00001000 03:05 147482 /lib/libdl-2.3.3.so
4002f000-40171000 r-xp 00000000 03:05 147511 /lib/tls/libc-2.3.3.so
40171000-40174000 rw-p 00142000 03:05 147511 /lib/tls/libc-2.3.3.so
40174000-40177000 rw-p 00000000 00:00 0
40177000-40178000 r--p 00000000 03:05 184085 /usr/share/locale/en_US/LC_NUMERIC
40178000-401a4000 r--p 00000000 03:05 183688 /usr/share/locale/ISO-8859-1/LC_CTYPE
401a4000-401a5000 r-xp 00000000 03:05 180462 /usr/lib/gconv/ISO8859-1.so
401a5000-401a6000 rw-p 00001000 03:05 180462 /usr/lib/gconv/ISO8859-1.so
401b3000-401bd000 r-xp 00000000 03:05 147492 /lib/libnss_files-2.3.3.so
401bd000-401be000 rw-p 00009000 03:05 147492 /lib/libnss_files-2.3.3.so
bfffa000-c0000000 rwxp ffffb000 00:00 0
ffffe000-fffff000 ---p 00000000 00:00 0