获取过去一小时内，系统内进程的内存占用
adb shell dumpsys procstats –hours 1

  • com.haodingdan.sixin:channel / u0a105 / v65:
    TOTAL: 87% (39MB-42MB-43MB/29MB-31MB-32MB/117MB-120MB-121MB over 7)
    Service: 87% (39MB-42MB-43MB/29MB-31MB-32MB/117MB-120MB-121MB over 7)
    Service Rs: 0.03%
  • com.haodingdan.sixin / u0a105 / v65:
    TOTAL: 85% (87MB-156MB-235MB/69MB-123MB-203MB/172MB-264MB-344MB over 588)
    Top: 85% (87MB-156MB-235MB/69MB-123MB-203MB/172MB-264MB-344MB over 588)
    Service Rs: 0.02%
    (Last Act): 2.7%

每个进程会显示3组内存占用, 每组中的三个数字是最小值，平均值，最大值, 三种占用是PSS, USS, RSS, 合起来是：
（minPSS-avgPSS-maxPSS/minUSS-avgUSS-maxUSS/minRSS-avgRSS-maxRSS over 样本数）

  • USS: Unique Set Size 独占内存大小（不包含共享库占用的内存），如果这个app被杀死，那么这部分内存会被释放
  • PSS: Proportional Set Size 按比例分摊的内存大小（比例分配共享库占用的内存）
    共享库占用的内存的“按比例分配”到底是怎么分配，据说是按进程数均摊：
    Pss is the amount of memory shared with other processes, accounted in a way that the amount is divided evenly between the processes that share it.
    只要有一个进程使用共享库，它就会一直占用内存。（共享库在没有进程需要它后，它是否会释放？）
  • RSS: Resident Set Size 常驻内存大小（包含共享库占用的内存），这个是不准确的

所以内存占用大小有如下规律：RSS >= PSS >= USS

Android studio的memory profiler的时间线上显示的内存，对比大小可能是USS或者PSS 根据文档: https://developer.android.com/studio/profile/memory-profiler?hl=en#how-counted 应该是只包含app独占的内存, 因此应该是USS

The numbers you see at the top of the Memory >Profiler (figure 2) are based on all the private >memory pages that your app has committed, according >to the Android system. This count does not include >pages shared with the system or other apps.

meminfo可以显示更多详细的数据，甚至还会获取View的个数ViewRootImple(窗口)的个数，打开的数据库的个数 其中“All Dalvik and native heap allocations you make will be private dirty RAM” Java和native代码在堆中创建的对对象都属于私有脏内存

adb shell dumpsys meminfo com.haodingdan.sixin [-d]

Applications Memory Usage (in Kilobytes): Uptime: 5838138 Realtime: 5838138

** MEMINFO in pid 8552 [com.haodingdan.sixin] ** Pss Private Private SwapPss Heap Heap Heap Total Dirty Clean Dirty Size Alloc Free —— —— —— —— —— —— —— Native Heap 36767 36484 0 0 50852 48485 2366 Dalvik Heap 7300 7004 0 0 13406 7278 6128 Dalvik Other 2431 2424 0 0
Stack 84 84 0 0
Cursor 48 48 0 0
Ashmem 85 0 0 0
Other dev 52 0 52 0
.so mmap 14396 144 5832 0
.jar mmap 3237 0 508 0
.apk mmap 21201 124 6456 0
.ttf mmap 283 0 100 0
.dex mmap 18480 18112 268 0
.oat mmap 445 0 64 0
.art mmap 7049 6224 68 0
Other mmap 4813 328 1336 1
Unknown 2573 2560 0 1
TOTAL 119246 73536 14684 2 64258 55763 8494

App Summary Pss(KB) —— Java Heap: 13296 Native Heap: 36484 Code: 31608 Stack: 84 Graphics: 0 Private Other: 6748 System: 31026

          TOTAL:   119246       TOTAL SWAP PSS:        2

Objects Views: 396 ViewRootImpl: 1 AppContexts: 5 Activities: 1 Assets: 4 AssetManagers: 0 Local Binders: 77 Proxy Binders: 39 Parcel memory: 22 Parcel count: 92 Death Recipients: 2 OpenSSL Sockets: 1 WebViews: 1

SQL MEMORY_USED: 1071 PAGECACHE_OVERFLOW: 543 MALLOC_SIZE: 117

DATABASES pgsz dbsz Lookaside(b) cache Dbname 4 76 98 9/39/7 /data/user/0/com.haodingdan.sixin/databases/androidx.work.workdb 4 12 0/0/0 (attached) temp 4 528 109 416/43/23 /data/user/0/com.haodingdan.sixin/databases/user_357262.db 4 20 37 1/16/2 /data/user/0/com.haodingdan.sixin/databases/accs.db