（一）DDMS 的Heap Dump
1) Data Object：java object.
2) Class Object：object of type Class, e.g. what you'd get from java.lang.String.class or myObject.getClass( ).
3) 1,2,4,8-byte array：Number of bytes per entry.
1-byte array: byte, boolean
2-byte array: char, short
4-byte array: float, int
8-byte array: double, long
4) non-Java object：A non-Java Object is a piece of memory that isn't actually accessible from code written in Java. Essentially it's a blob of stuff that got stuck on the virtual heap but has no meaning to interpreted code. Shouldn't be much of that.----------------------------------------------------
需要root權限同時要支持以下命令的Android工程機
1：root@android:/ # procrank 查看所有進程的內存信息包括：PID Vss Rss Pss Uss cmdline
root@android:/ # procrank warning: could not create process interface for 32099 PID Vss Rss Pss Uss cmdline 17690 75152K 75020K 40491K 38024K com.dianxinos.optimizer.channel 13968 124792K 61864K 35726K 34372K com.dianxinos.optimizer.channel 1516 65052K 64940K 29661K 27076K android.process.acore 1322 88028K 65764K 29581K 26156K system_server 1417 68320K 63892K 28635K 25820K com.android.systemui 1757 55040K 54960K 21176K 19084K com.qihoo360.mobilesafe_mtk6573 12294 45208K 45096K 13238K 11220K android.process.acore 29904 44984K 44896K 12227K 10316K com.dianxinos.optimizer.engine.demo:service 29819 61032K 44624K 11772K 9808K com.dianxinos.optimizer.engine.demo 13284 40556K 40448K 9823K 8472K com.qihoo.appstore 1499 40036K 39940K 9095K 7700K com.android.phone 1478 39988K 39880K 8998K 7588K com.cootek.smartinputv5 12497 36860K 36736K 6975K 5844K android.process.media 12910 36420K 36336K 6754K 5640K com.cnnet.fknjjzw 25083 36772K 36640K 6413K 5180K com.google.process.gapps 26667 36660K 36512K 6323K 5008K com.qihoo.browser 1297 40400K 40240K 5366K 2804K zygote 30870 34424K 34284K 4495K 3264K com.android.contacts 31078 34304K 34164K 4338K 3188K com.android.providers.calendar 11595 33692K 33552K 4064K 2796K net.qihoo.launcher.widget.clockweather:WeatherService 30623 33720K 33576K 4005K 2748K com.android.settings 31103 33980K 33836K 3973K 2768K com.android.calendar
2：root@android:/ # showmap 29904 查看指定Pid的內存具體信息
root@android:/ # showmap 29904 virtual shared shared private private size RSS PSS clean dirty clean dirty # object -------- -------- -------- -------- -------- -------- -------- ---- ------------------------------ 124 124 17 124 0 0 0 3 /data/app/com.dianxinos.optimizer.engine.demo-2.apk 1400 708 351 676 0 32 0 1 /data/dalvik-cache/data@app@com.dianxinos.optimizer.engine.demo-2.apk@classes.dex 328 148 15 148 0 0 0 1 /data/dalvik-cache/system@framework@android.policy.jar@classes.dex 1348 32 1 32 0 0 0 1 /data/dalvik-cache/system@framework@apache-xml.jar@classes.dex 956 344 54 344 0 0 0 1 /data/dalvik-cache/system@framework@bouncycastle.jar@classes.dex 4 4 0 4 0 0 0 1 /data/dalvik-cache/system@framework@com.qrd.plugin.feature_query.jar@classes.dex 8 8 0 8 0 0 0 1 /data/dalvik-cache/system@framework@com.qrdinside.impl.jar@classes.dex 24 8 0 8 0 0 0 1 /data/dalvik-cache/system@framework@core-junit.jar@classes.dex 3288 1372 68 1372 0 0 0 1 /data/dalvik-cache/system@framework@core.jar@classes.dex 1460 96 5 96 0 0 0 1 /data/dalvik-cache/system@framework@ext.jar@classes.dex 316 16 0 16 0 0 0 1 /data/dalvik-cache/system@framework@filterfw.jar@classes.dex 11476 4616 316 4588 20 8 0 11 /data/dalvik-cache/system@framework@framework.jar@classes.dex 2208 48 2 48 0 0 0 1 /data/dalvik-cache/system@framework@services.jar@classes.dex 64 40 0 0 40 0 0 1 /dev/__properties__ (deleted) 24 4 2 0 4 0 0 1 /dev/ashmem/InputChannel 41a89fb0 com.dianxinos.optimizer.engine.demo/com.dianxinos.optimizer.engine.demo.antispam.AntiSpamActi 4 4 0 4 0 0 0 1 /dev/ashmem/SurfaceFlinger read-only heap (deleted) 8192 2864 249 0 2712 0 152 4 /dev/ashmem/dalvik-LinearAlloc (deleted) 2048 0 0 0 0 0 0 1 /dev/ashmem/dalvik-bitmap-1 (deleted) 2048 220 220 0 0 0 220 1 /dev/ashmem/dalvik-bitmap-2 (deleted) 1028 128 128 0 0 0 128 1 /dev/ashmem/dalvik-card-table (deleted) 131072 16136 7117 0 9356 0 6780 3 /dev/ashmem/dalvik-heap (deleted) 1024 96 96 0 0 0 96 1 /dev/ashmem/dalvik-jit-code-cache (deleted) 43692 0 0 0 0 0 0 1 /dev/ashmem/dalvik-mark-stack (deleted) 1016 4 4 0 0 4 0 1 /dev/binder 12 8 0 4 4 0 0 2 /system/bin/app_process 36 24 4 20 0 0 4 2 /system/bin/linker 360 24 3 24 0 0 0 1 /system/fonts/DroidNaskh-Regular.ttf 16 12 1 12 0 0 0 1 /system/fonts/DroidSansArmenian.ttf 224 16 2 16 0 0 0 1 /system/fonts/DroidSansEthiopic-Regular.ttf 5176 764 147 748 0 16 0 1 /system/fonts/DroidSansFallback.ttf 24 12 1 12 0 0 0 1 /system/fonts/DroidSansGeorgian.ttf 32 16 4 16 0 0 0 1 /system/fonts/DroidSansHebrew-Bold.ttf 32 16 2 16 0 0 0 1 /system/fonts/DroidSansHebrew-Regular.ttf 36 16 2 16 0 0 0 1 /system/fonts/DroidSansThai.ttf 140 8 1 8 0 0 0 1 /system/fonts/Lohit-Bengali.ttf 64 16 2 16 0 0 0 1 /system/fonts/Lohit-Devanagari.ttf 68 8 1 8 0 0 0 1 /system/fonts/Lohit-Tamil.ttf 80 12 3 12 0 0 0 1 /system/fonts/Roboto-Bold.ttf 80 16 2 16 0 0 0 1 /system/fonts/Roboto-Regular.ttf 4 0 0 0 0 0 0 1 /system/framework/android.policy.jar 8 0 0 0 0 0 0 1 /system/framework/apache-xml.jar 4 0 0 0 0 0 0 1 /system/framework/bouncycastle.jar 4 0 0 0 0 0 0 1 /system/framework/com.qrd.plugin.feature_query.jar 4 0 0 0 0 0 0 1 /system/framework/com.qrdinside.impl.jar 4 0 0 0 0 0 0 1 /system/framework/core-junit.jar 4 0 0 0 0 0 0 1 /system/framework/core.jar 64 0 0 0 0 0 0 1 /system/framework/ext.jar 4 0 0 0 0 0 0 1 /system/framework/filterfw.jar 944 212 25 212 0 0 0 2 /system/framework/framework-res.apk 4 0 0 0 0 0 0 1 /system/framework/framework.jar 4 0 0 0 0 0 0 1 /system/framework/services.jar 20 20 9 12 0 0 8 2 /system/lib/hw/gralloc.msm7627a.so 152 80 5 52 24 0 4 3 /system/lib/libEGL.so 12 8 0 0 8 0 0 2 /system/lib/libETC1.so 24 16 0 8 8 0 0 2 /system/lib/libGLESv1_CM.so 20 16 0 8 8 0 0 2 /system/lib/libGLESv2.so 128 84 2 72 12 0 0 2 /system/lib/libGLESv2_dbg.so 24 20 0 12 8 0 0 2 /system/lib/libQcomUI.so 640 272 132 124 20 0 128 3 /system/lib/libRS.so 56 52 1 40 12 0 0 2 /system/lib/libandroid.so 704 616 24 568 44 0 4 2 /system/lib/libandroid_runtime.so 4276 796 27 576 220 0 0 3 /system/lib/libbcc.so 844 220 7 204 16 0 0 2 /system/lib/libbcinfo.so 164 156 7 128 24 0 4 2 /system/lib/libbinder.so 12 8 0 0 8 0 0 2 /system/lib/libbluedroid.so 320 228 19 188 24 0 16 3 /system/lib/libc.so 124 120 3 96 24 0 0 2 /system/lib/libcamera_client.so 2472 1040 35 964 76 0 0 3 /system/lib/libchromium_net.so 8 8 0 0 8 0 0 2 /system/lib/libcnefeatureconfig.so 816 476 14 400 76 0 0 3 /system/lib/libcrypto.so 120 44 5 36 4 0 4 3 /system/lib/libcutils.so 300 56 1 48 8 0 0 2 /system/lib/libdbus.so 92 84 2 68 16 0 0 2 /system/lib/libdrmframework.so 748 640 50 580 44 0 16 3 /system/lib/libdvm.so 28 20 8 4 8 0 8 3 /system/lib/libemoji.so 52 12 0 4 8 0 0 3 /system/lib/libexif.so 80 8 0 0 8 0 0 2 /system/lib/libexpat.so 176 28 0 16 12 0 0 2 /system/lib/libflex.so 16 16 0 8 8 0 0 2 /system/lib/libgabi++.so 8 8 8 0 0 0 8 2 /system/lib/libgenlock.so 60 56 1 40 16 0 0 2 /system/lib/libgesture_client.so 216 208 10 168 36 0 4 2 /system/lib/libgui.so 8 8 0 0 8 0 0 2 /system/lib/libhardware.so 24 12 0 4 8 0 0 2 /system/lib/libhardware_legacy.so 256 52 1 44 8 0 0 2 /system/lib/libharfbuzz.so 140 60 2 48 12 0 0 2 /system/lib/libhwui.so 1168 700 28 672 24 0 4 2 /system/lib/libicui18n.so 992 692 36 644 36 0 12 3 /system/lib/libicuuc.so 216 20 0 12 8 0 0 2 /system/lib/libjpeg.so 16 16 0 8 8 0 0 2 /system/lib/liblog.so 92 52 5 40 8 0 4 3 /system/lib/libm.so 436 376 19 308 64 0 4 2 /system/lib/libmedia.so 88 84 2 72 12 0 0 2 /system/lib/libmedia_jni.so 24 24 4 16 4 0 4 2 /system/lib/libmemalloc.so 76 40 1 28 12 0 0 2 /system/lib/libmtp.so 216 176 5 160 16 0 0 2 /system/lib/libnativehelper.so 24 12 0 4 8 0 0 2 /system/lib/libnetutils.so 8 8 0 0 8 0 0 2 /system/lib/libnfc_ndef.so 972 112 3 92 20 0 0 3 /system/lib/libnode.so 112 60 1 48 12 0 0 2 /system/lib/libpixelflinger.so 16 16 0 8 8 0 0 2 /system/lib/libpowermanager.so 12 12 0 4 8 0 0 2 /system/lib/libqc-opt.so 8 8 0 0 8 0 0 2 /system/lib/libqrdinside.so 24 24 0 16 8 0 0 2 /system/lib/librs_jni.so 1228 836 49 804 24 0 8 3 /system/lib/libskia.so 336 20 0 12 8 0 0 3 /system/lib/libsonivox.so 328 304 15 292 8 0 4 2 /system/lib/libsqlite.so 184 116 3 96 20 0 0 2 /system/lib/libssl.so 1496 416 14 368 48 0 0 2 /system/lib/libstagefright.so 52 12 0 4 8 0 0 2 /system/lib/libstagefright_amrnb_common.so 40 16 4 4 8 0 4 3 /system/lib/libstagefright_avc_common.so 8 8 0 0 8 0 0 2 /system/lib/libstagefright_enc_common.so 44 36 1 28 8 0 0 2 /system/lib/libstagefright_foundation.so 12 8 0 0 8 0 0 2 /system/lib/libstagefright_yuv.so 8 8 0 0 8 0 0 2 /system/lib/libstdc++.so 208 16 4 8 4 0 4 2 /system/lib/libstlport.so 16 16 0 8 8 0 0 2 /system/lib/libtilerenderer.so 92 80 7 68 8 0 4 2 /system/lib/libui.so 12 8 0 0 8 0 0 2 /system/lib/libusbhost.so 188 172 8 160 8 0 4 2 /system/lib/libutils.so 2680 512 17 428 84 0 0 3 /system/lib/libv8.so 100 20 0 8 12 0 0 2 /system/lib/libvorbisidec.so 6364 1724 59 1200 524 0 0 3 /system/lib/libwebcore.so 12 12 0 4 8 0 0 2 /system/lib/libwpa_client.so 96 52 1 44 8 0 0 2 /system/lib/libz.so 36 8 0 0 8 0 0 2 /system/lib/libzipfile.so 14304 144 10 144 0 0 0 2 /system/usr/icu/icudt46l.dat 476 0 0 0 0 0 0 1 /system/usr/share/zoneinfo/zoneinfo.dat 9896 1392 978 0 432 0 960 29 [anon] 2756 2752 1675 0 1120 0 1632 2 [heap] 1160 28 24 0 4 0 24 3 [stack] 4 4 4 0 0 0 4 1 [vectors] -------- -------- -------- -------- -------- -------- -------- ---- ------------------------------ virtual shared shared private private size RSS PSS clean dirty clean dirty # object -------- -------- -------- -------- -------- -------- -------- ---- ------------------------------ 280360 44900 12195 18956 15624 60 10260 277 TOTAL
3: dumpsys meminfo 包名
4: VSS/RSS/PSS/USS 的區別
- VSS - Virtual Set Size 虛擬耗用內存（包含共享庫占用的內存）
- RSS - Resident Set Size 實際使用物理內存（包含共享庫占用的內存）
- PSS - Proportional Set Size 實際使用的物理內存（比例分配共享庫占用的內存）
- USS - Unique Set Size 進程獨自占用的物理內存（不包含共享庫占用的內存）
一般來說內存占用大小有如下規律：VSS >= RSS >= PSS >= USS
Overview
The aim of this post is to provide information that will assist in interpreting memory reports from various tools so the true memory usage for Linux processes and the system can be determined.
Android has a tool called procrank (/system/xbin/procrank), which lists out the memory usage of Linux processes in order from highest to lowest usage. The sizes reported per process are VSS, RSS, PSS, and USS.
For the sake of simplicity in this description, memory will be expressed in terms of pages, rather than bytes. Linux systems like ours manage memory in 4096 byte pages at the lowest level.
VSS (reported as VSZ from ps) is the total accessible address space of a process. This size also includes memory that may not be resident in RAM like mallocs that have been allocated but not written to. VSS is of very little use for determing real memory usage of a process.
RSS is the total memory actually held in RAM for a process. RSS can be misleading, because it reports the total all of the shared libraries that the process uses, even though a shared library is only loaded into memory once regardless of how many processes use it. RSS is not an accurate representation of the memory usage for a single process.
PSS differs from RSS in that it reports the proportional size of its shared libraries, i.e. if three processes all use a shared library that has 30 pages, that library will only contribute 10 pages to the PSS that is reported for each of the three processes. PSS is a very useful number because when the PSS for all processes in the system are summed together, that is a good representation for the total memory usage in the system. When a process is killed, the shared libraries that contributed to its PSS will be proportionally distributed to the PSS totals for the remaining processes still using that library. In this way PSS can be slightly misleading, because when a process is killed, PSS does not accurately represent the memory returned to the overall system.
USS is the total private memory for a process, i.e. that memory that is completely unique to that process. USS is an extremely useful number because it indicates the true incremental cost of running a particular process. When a process is killed, the USS is the total memory that is actually returned to the system. USS is the best number to watch when initially suspicious of memory leaks in a process.
For systems that have Python available, there is also a nice tool called smem that will report memory statistics including all of these categories.
5：通過Android系統提供的Runtime類，執行adb 命令(top,procrank,ps...等命令)查詢
通過對執行結果的標准控制台輸出進行解析。這樣大大的擴展了Android查詢功能.例如：
final Process m_process = Runtime.getRuntime().exec("/system/bin/top -n 1");
final StringBuilder sbread = new StringBuilder();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(m_process.getInputStream()), 8192);
# procrank
Runtime.getRuntime().exec("/system/xbin/procrank");
6：android.os.Debug查詢PSS，VSS，USS等單個進程使用內存信息
MemoryInfo[] memoryInfoArray = am.getProcessMemoryInfo(pids); MemoryInfo pidMemoryInfo=memoryInfoArray[0]; pidMemoryInfo.getTotalPrivateDirty(); //Return total private dirty memory usage in kB. USS
7:root@android:/ # cat /proc/meminfo
使用adb shell cat /proc/meminfo 命令，查看剩余的空間還有多少，通常的系統剩余空間是: MemFree + cached
MemTotal: 483724 kB
MemFree: 5616 kB
Buffers: 2732 kB
Cached: 158632 kB
SwapCached: 0 kB
Active: 277336 kB
Inactive: 83232 kB
Active(anon): 197452 kB
root@android:/ # cat /proc/meminfo MemTotal: 835616 kB MemFree: 251068 kB Buffers: 42128 kB Cached: 218088 kB SwapCached: 0 kB Active: 402312 kB Inactive: 116296 kB Active(anon): 261152 kB Inactive(anon): 300 kB Active(file): 141160 kB Inactive(file): 115996 kB Unevictable: 2728 kB Mlocked: 0 kB HighTotal: 121856 kB HighFree: 416 kB LowTotal: 713760 kB LowFree: 250652 kB SwapTotal: 0 kB SwapFree: 0 kB Dirty: 40 kB Writeback: 0 kB AnonPages: 261132 kB Mapped: 66860 kB Shmem: 348 kB Slab: 23940 kB SReclaimable: 13876 kB SUnreclaim: 10064 kB KernelStack: 5296 kB PageTables: 8652 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 417808 kB Committed_AS: 3873120 kB VmallocTotal: 196608 kB VmallocUsed: 163088 kB VmallocChunk: 11204 kB
8:
[root@localhost ~]# vmstat -n 3 (每個3秒刷新一次）
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
1 0 144 186164 105252 2386848 0 0 18 166 83 2 48 21 31 0
2 0 144 189620 105252 2386848 0 0 0 177 1039 1210 34 10 56 0
0 0 144 214324 105252 2386848 0 0 0 10 1071 670 32 5 63 0
0 0 144 202212 105252 2386848 0 0 0 189 1035 558 20 3 77 0
2 0 144 158772 105252 2386848 0 0 0 203 1065 2832 70 14 15 0
vmstat所帶參數請用man vmstat查看
Procs
r: 等待運行的進程數 b: 處在非中斷睡眠狀態的進程數 w: 被交換出去的可運行的進程數。此數由 linux 計算得出，但 linux 並不耗盡交換空間
Memory
swpd: 虛擬內存使用情況，單位：KB
free: 空閑的內存，單位KB
buff: 被用來做為緩存的內存數，單位：KB
Swap
si: 從磁盤交換到內存的交換頁數量，單位：KB/秒
so: 從內存交換到磁盤的交換頁數量，單位：KB/秒
IO
bi: 發送到塊設備的塊數，單位：塊/秒
bo: 從塊設備接收到的塊數，單位：塊/秒
System
in: 每秒的中斷數，包括時鍾中斷
cs: 每秒的環境（上下文）切換次數
CPU
按 CPU 的總使用百分比來顯示
us: CPU 使用時間
sy: CPU 系統使用時間
id: 閑置時間
准測
r，b≈0，
如果fre，將會出現連續不斷的頁面調度，將導致系統性能問題。
對於page列，re，pi，po，cy維持於比較穩定的狀態，PI率不超過5，如果有pagin發生，那么關聯頁面必須先進行pageout
在內存相對緊張的環境下pagein會強制對不同的頁面進行steal操作。如果系統正在讀一個大批的永久頁面，你也許可以看到po和pi列
會出現不一致的增長，這種情景並不一定表明系統負載過重，但是有必要對應用程序的數據訪問模式進行見檢查。在穩定的情況下，掃描率和重置率幾乎相等，在
多個進程處理使用不同的頁面的情況下，頁面會更加不穩定和雜亂，這時掃描率可能會比重置率高出。
faults列，in，sy，cs會不斷跳躍，這里沒有明確的限制，唯一的就是這些值最少大於100
cpu列，us，sys，id和wa也是不確定的，最理想的狀態是使cpu處於100%工作狀態，單這只適合單用戶的情況下。
如果在多用戶環境中us＋sys》80，進程就會在運行隊列中花費等待時間，響應時間和吞吐量就會下降。wa>40表明磁盤io沒有也許存在不合理的平衡，或者對磁盤操作比較頻繁，
vmstat各項：
procs:
r-->在運行隊列中等待的進程數
b-->在等待io的進程數
w-->可以進入運行隊列但被替換的進程
memoy
swap-->現時可用的交換內存（k表示）
free-->空閑的內存（k表示）
pages
re－－》回收的頁面
mf－－》非嚴重錯誤的頁面
pi－－》進入頁面數（k表示）
po－－》出頁面數（k表示）
fr－－》空余的頁面數（k表示）
de－－》提前讀入的頁面中的未命中數
sr－－》通過時鍾算法掃描的頁面
disk 顯示每秒的磁盤操作。 s表示scsi盤，0表示盤號
fault 顯示每秒的中斷數
in－－》設備中斷
sy－－》系統中斷
cy－－》cpu交換
cpu 表示cpu的使用狀態
cs－－》用戶進程使用的時間
sy－－》系統進程使用的時間
id－－》cpu空閑的時間
如果 r經常大於 4 ，且id經常少於40，表示cpu的負荷很重。
如果pi，po 長期不等於0，表示內存不足。
如果disk 經常不等於0， 且在 b中的隊列 大於3， 表示 io性能不好。
Linux在具有高穩定性、可靠性的同時，具有很好的可伸縮性和擴展性，能夠針對不同的應用和硬件環境調整，優化出滿足當前應用需要的最佳性能。因此企業在維護Linux系統、進行系統調優時，了解系統性能分析工具是至關重要的。
在Linux下有很多系統性能分析工具，比較常見的有top、free、ps、time、timex、uptime等。下文將介紹幾個較為重要的性能分析工具vmstat、iostat和sar及其使用。
用vmstat監視內存使用情況
vmstat是Virtual Meomory Statistics（虛擬內存統計）的縮寫，可對操作系統的虛擬內存、進程、CPU活動進行監視。它是對系統的整體情況進行統計，不足之處是無法對某個進程進行深入分析。
vmstat的語法如下：
vmstat [-V] [-n] [delay [count]]
其中，－V表示打印出版本信息；－n表示在周期性循環輸出時，輸出的頭部信息僅顯示一次；delay是兩次輸出之間的延遲時間；count是指按照這個時間間隔統計的次數。對於vmstat輸出各字段的含義，可運行man vmstat查看
root@android:/ # procrank