Android 查看进程内存的方式

ゞ浴缸里的玫瑰 2022-05-31 04:16 306阅读 0赞

查看Android系统，单个进程、多个进程内存的使用情况，通常有那些方法：

1，通过Android API函数

使用ActivityManager查看可用内存，具体是其内部类MemoryInfo。

ActivityManager.MemoryInfo memInfo = new ActivityManager.MemoryInfo();
    
    am.getMemoryInfo(memInfo);

然后通过实例meminfo中的变量读取相关内存信息，如：

public long availMem;

public long totalMem;

public boolean lowMemory;　//表示系统是否处于低内存

public long threshold; //表示系统剩余内存低于多少时，认为是低内存。

另外，framework/base/core/java/android/os/Debug.java中，也有一个MemoryInfo内部类，通过它可以查询PSS，VSS，USSS等单个进程使用内存的信息，如：

int appPID = Process.myPid();            
                int pids[] = new int[1];
                pids[0] = appPID;
                Debug.MemoryInfo[] memoryInfoArray = mActivityManager.getProcessMemoryInfo(pids);
                totalPrivateDirty = memoryInfoArray[0].getTotalPrivateDirty() / BYTES_IN_KILOBYTE;
                totalSharedDirty = memoryInfoArray[0].getTotalSharedDirty() / BYTES_IN_KILOBYTE;
                totalPSS = memoryInfoArray[0].getTotalPss() / BYTES_IN_KILOBYTE;
                nativePSS = memoryInfoArray[0].nativePss / BYTES_IN_KILOBYTE;
                dalvikPSS = memoryInfoArray[0].dalvikPss / BYTES_IN_KILOBYTE;
                otherPSS = memoryInfoArray[0].otherPss / BYTES_IN_KILOBYTE;

这个方式可以得到比较详细的内存使用情况，单位ｋｂ，系统中很多内存是进程间共享的，所以某个进程具体使用多少内存是很难精确统计的：

/** The proportional set size for dalvik heap.  (Doesn't include other Dalvik overhead.) */
            public int dalvikPss;
            /** The proportional set size that is swappable for dalvik heap. */
            /** @hide We may want to expose this, eventually. */
            public int dalvikSwappablePss;
            /** The private dirty pages used by dalvik heap. */
            public int dalvikPrivateDirty;
            /** The shared dirty pages used by dalvik heap. */
            public int dalvikSharedDirty;
            /** The private clean pages used by dalvik heap. */
            /** @hide We may want to expose this, eventually. */
            public int dalvikPrivateClean;
            /** The shared clean pages used by dalvik heap. */
            /** @hide We may want to expose this, eventually. */
            public int dalvikSharedClean;
            /** The dirty dalvik pages that have been swapped out. */
            /** @hide We may want to expose this, eventually. */
            public int dalvikSwappedOut;
            /** The dirty dalvik pages that have been swapped out, proportional. */
            /** @hide We may want to expose this, eventually. */
            public int dalvikSwappedOutPss;
    
            /** The proportional set size for the native heap. */
            public int nativePss;
            /** The proportional set size that is swappable for the native heap. */
            /** @hide We may want to expose this, eventually. */
            public int nativeSwappablePss;
            /** The private dirty pages used by the native heap. */
            public int nativePrivateDirty;
            /** The shared dirty pages used by the native heap. */
            public int nativeSharedDirty;
            /** The private clean pages used by the native heap. */
            /** @hide We may want to expose this, eventually. */
            public int nativePrivateClean;
            /** The shared clean pages used by the native heap. */
            /** @hide We may want to expose this, eventually. */
            public int nativeSharedClean;
            /** The dirty native pages that have been swapped out. */
            /** @hide We may want to expose this, eventually. */
            public int nativeSwappedOut;
            /** The dirty native pages that have been swapped out, proportional. */
            /** @hide We may want to expose this, eventually. */
            public int nativeSwappedOutPss;
    
            /** The proportional set size for everything else. */
            public int otherPss;
            /** The proportional set size that is swappable for everything else. */
            /** @hide We may want to expose this, eventually. */
            public int otherSwappablePss;
            /** The private dirty pages used by everything else. */
            public int otherPrivateDirty;
            /** The shared dirty pages used by everything else. */
            public int otherSharedDirty;
            /** The private clean pages used by everything else. */
            /** @hide We may want to expose this, eventually. */
            public int otherPrivateClean;
            /** The shared clean pages used by everything else. */
            /** @hide We may want to expose this, eventually. */
            public int otherSharedClean;
            /** The dirty pages used by anyting else that have been swapped out. */
            /** @hide We may want to expose this, eventually. */
            public int otherSwappedOut;
            /** The dirty pages used by anyting else that have been swapped out, proportional. */
            /** @hide We may want to expose this, eventually. */
            public int otherSwappedOutPss;
    
            /** Whether the kernel reports proportional swap usage */
            /** @hide */
            public boolean hasSwappedOutPss;

其中Dalvik:　是dalvik所使用的内存；

native :是被native堆使用的内存，通常指使用c/c++在堆上分配的内存。

other: 指除去dalvik,native使用的内存，比如分配在栈上的内存。

private: 指私有的，非共享的

share:指共享的内存。

privateDirty:　指非共享的，又不能换页出去的内存大小，如linux为了提高分配内存速度而缓冲的小对象，即使进程结束，该内存也不会释放，只是又重新回到缓冲中。

sharedDirty :指共享的，又不能换页出去的内存大小。

MemoryInfo　描述的内存使用情况可以通过命令adb shell dumpsys meminfo processName/ID得到。

通过public Debug.MemoryInfo\[\] getProcessMemoryInfo(int\[\] pids) ＠ActivityManager.java可以同时得到多个进程的内存使用情况。

通过public static native void getMemInfo(long\[\] outSizes)＠Debug.java得到单个进程的内存使用情况。

通过public List<RunningAppProcessInfo> getRunningAppProcesses() @ActivityManager.java获取当前运行的所有进程的信息，其中RunningAppProcessInfo中有进程名字，进程id。

2，直接对Android文件进行解析

Android严格说只是一个在linux内核上跑的应用程序，所以一般应用程序的内存使用还是采用Linux的传统方法，因此能通过 proc/ 文件系统的meminfo来分析系统的内存使用情况。/proc/cpuinfo中保存了cpu的相关信息，/proc/meminfo/中保存了系统内存的使用信息。比如proc/meminfo中的信息：

MemTotal : \*\*\*kb

MemFree: \*\*kb

Buffers :\*\*kb

Cached :\*\* kb

系统在运行过程中memfree通过很小，以为系统会尽可能地cache和buffer一些数据，提高下次执行的速度，但是实际这些内存也是可以随时被拿来使用的，所以空闲内存通常是free+cached+buffers，也即是total-used。

3，通过Runtime类查看

通过Android系统的Runtime类，然后执行adb 命令（top，procrank，ps等）可以实现查询功能，通过将执行结果进行解析，就扩展了Android的查询功能。如：

public String captureMediaserverInfo() {
            String cm = "ps mediaserver";
            String memoryUsage = null;
    
            int ch;
            try {
                Process p = Runtime.getRuntime().exec(cm);
                InputStream in = p.getInputStream();
                StringBuffer sb = new StringBuffer(512);
                while ((ch = in.read()) != -1) {
                    sb.append((char) ch);
                }
                memoryUsage = sb.toString();
            } catch (IOException e) {
                Log.v(TAG, e.toString());
            }
            String[] poList = memoryUsage.split("\r|\n|\r\n");
            // A new media.log is enabled with ro.test_harness is set.
            // The output of "ps mediaserver" will include the
            // media.log process in the first line. Update the parsing
            // to only read the thrid line.
            // Smaple ps mediaserver output:
            // USER     PID   PPID  VSIZE  RSS     WCHAN    PC         NAME
            // media     131   1     13676  4796  ffffffff 400b1bd0 S media.log
            // media     219   131   37768  6892  ffffffff 400b236c S /system/bin/mediaserver
            String memusage = poList[poList.length-1].concat("\n");
            return memusage;
        }

类似的命令"system/bin/top -n l"，"system/bin/procrank"，内存消耗的表示：

VSS：virtual set size ，虚拟耗用内存（包含共享库占用的内存）。

RSS： Resident Set Size ，实际使用物理内存（包含共享库占用的内存）。

PSS：Proportional Set Size，实际使用的物理内存（比例分配共享库占用的内存）。

USS：Unique Set Size，进程独自占用的物理内存（不包括共享库占用的内存）。

4，通过DDMS工具（Dalvik debug Monitor Service）

可以查看内存，cpu的使用情况。

选中要检测的进程，单击Update Heap 图标，然后点击Heap试图中的 CauseGC按钮，在Ｈｅａｐ试图中可以看到当前选中进程的内存使用情况。

５，使用Debug的方法

public static native long getNativeHeapSize();　//返回当前进程native堆总的内存大小。

public static native long getNativeHeapFreeSize();//返回当前native堆中剩余内存大小。

public static native long getNativeHeapAllocatedSize();//返回当前进程native堆中已使用内存大小。