以编程方式检索 iPhone 上的内存使用情况

Question

我正在尝试以编程方式随时检索我的 iPhone 应用程序正在使用的内存量。是的，我知道 ObjectAlloc/Leaks。我对这些不感兴趣，只是想知道是否可以编写一些代码并获取正在使用的字节数并通过 NSLog 报告。

谢谢。

Answer 1

要获取您的应用程序正在使用的实际内存字节数，您可以执行以下示例中的操作。但是，您确实应该熟悉各种分析工具，因为它们旨在让您更好地了解总体使用情况。

#import <mach/mach.h>

// ...

void report_memory(void) {
  struct task_basic_info info;
  mach_msg_type_number_t size = TASK_BASIC_INFO_COUNT;
  kern_return_t kerr = task_info(mach_task_self(),
                                 TASK_BASIC_INFO,
                                 (task_info_t)&info,
                                 &size);
  if( kerr == KERN_SUCCESS ) {
    NSLog(@"Memory in use (in bytes): %lu", info.resident_size);
    NSLog(@"Memory in use (in MiB): %f", ((CGFloat)info.resident_size / 1048576));
  } else {
    NSLog(@"Error with task_info(): %s", mach_error_string(kerr));
  }
}

在结构 info.virtual_size 中还有一个字段，它将为您提供可用虚拟内存的字节数（或分配给您的应用程序的内存作为潜在的虚拟内存在任何情况下）。 pgb 链接到的代码将为您提供设备可用的内存量以及它是什么类型的内存。

Answer 2

这里的 report_memory() 得到了增强，可以在 NSLog() 中快速显示泄漏状态。

void report_memory(void) {
    static unsigned last_resident_size=0;
    static unsigned greatest = 0;
    static unsigned last_greatest = 0;

    struct task_basic_info info;
    mach_msg_type_number_t size = sizeof(info);
    kern_return_t kerr = task_info(mach_task_self(),
                               TASK_BASIC_INFO,
                               (task_info_t)&info,
                               &size);
    if( kerr == KERN_SUCCESS ) {
        int diff = (int)info.resident_size - (int)last_resident_size;
        unsigned latest = info.resident_size;
        if( latest > greatest   )   greatest = latest;  // track greatest mem usage
        int greatest_diff = greatest - last_greatest;
        int latest_greatest_diff = latest - greatest;
        NSLog(@"Mem: %10u (%10d) : %10d :   greatest: %10u (%d)", info.resident_size, diff,
          latest_greatest_diff,
          greatest, greatest_diff  );
    } else {
        NSLog(@"Error with task_info(): %s", mach_error_string(kerr));
    }
    last_resident_size = info.resident_size;
    last_greatest = greatest;
}

Answer 3

TASK_BASIC_INFO 的标头说：

/* Don't use this, use MACH_TASK_BASIC_INFO instead */

这是一个使用MACH_TASK_BASIC_INFO的版本：

void report_memory(void)
{
    struct mach_task_basic_info info;
    mach_msg_type_number_t size = MACH_TASK_BASIC_INFO_COUNT;
    kern_return_t kerr = task_info(mach_task_self(),
                                   MACH_TASK_BASIC_INFO,
                                   (task_info_t)&info,
                                   &size);
    if( kerr == KERN_SUCCESS ) {
        NSLog(@"Memory in use (in bytes): %u", info.resident_size);
    } else {
        NSLog(@"Error with task_info(): %s", mach_error_string(kerr));
    }
}

Answer 4

Jason Coco的快速解决方案@的回答：

func reportMemory() {
    let name = mach_task_self_
    let flavor = task_flavor_t(TASK_BASIC_INFO)
    let basicInfo = task_basic_info()
    var size: mach_msg_type_number_t = mach_msg_type_number_t(sizeofValue(basicInfo))
    let pointerOfBasicInfo = UnsafeMutablePointer<task_basic_info>.alloc(1)

    let kerr: kern_return_t = task_info(name, flavor, UnsafeMutablePointer(pointerOfBasicInfo), &size)
    let info = pointerOfBasicInfo.move()
    pointerOfBasicInfo.dealloc(1)

    if kerr == KERN_SUCCESS {
        print("Memory in use (in bytes): \(info.resident_size)")
    } else {
        print("error with task info(): \(mach_error_string(kerr))")
    }
}

Answer 5

这是一个 Swift 3 版本：

func mach_task_self() -> task_t {
    return mach_task_self_
}

func getMegabytesUsed() -> Float? {
    var info = mach_task_basic_info()
    var count = mach_msg_type_number_t(MemoryLayout.size(ofValue: info) / MemoryLayout<integer_t>.size)
    let kerr = withUnsafeMutablePointer(to: &info) { infoPtr in
        return infoPtr.withMemoryRebound(to: integer_t.self, capacity: Int(count)) { (machPtr: UnsafeMutablePointer<integer_t>) in
            return task_info(
                mach_task_self(),
                task_flavor_t(MACH_TASK_BASIC_INFO),
                machPtr,
                &count
            )
        }
    }
    guard kerr == KERN_SUCCESS else {
        return nil
    }  
    return Float(info.resident_size) / (1024 * 1024)   
}

Answer 6

Swift 3.1 （截至 2017 年 8 月 8 日）

func getMemory() {

    var taskInfo = mach_task_basic_info()
    var count = mach_msg_type_number_t(MemoryLayout<mach_task_basic_info>.size)/4
    let kerr: kern_return_t = withUnsafeMutablePointer(to: &taskInfo) {
        $0.withMemoryRebound(to: integer_t.self, capacity: 1) {
            task_info(mach_task_self_, task_flavor_t(MACH_TASK_BASIC_INFO), $0, &count)
        }
    }
    if kerr == KERN_SUCCESS {
        let usedMegabytes = taskInfo.resident_size/(1024*1024)
        print("used megabytes: \(usedMegabytes)")
    } else {
        print("Error with task_info(): " +
            (String(cString: mach_error_string(kerr), encoding: String.Encoding.ascii) ?? "unknown error"))
    }

}

Answer 7

这已于 2019 年 7 月 1 日在 Mojave 10.4.6 中的 Xcode 11 和 2020 年 11 月 5 日的 Xcode 11.3 上进行了测试

之前的所有答案都返回不正确的结果。

下面有两个Swift 版本。

这里是如何获得 Apple 的 Quinn “The Eskimo!”所写的期望值。

这使用了来自 Darwin > Mach > task_info 的 phys_footprint 变量，并且与 Xcode 调试导航器中的内存量表中的值非常匹配。

返回的值以字节为单位。

https://forums.developer.apple.com/thread/105088#357415

原始代码如下。

func memoryFootprint() -> mach_vm_size_t? {  
    // The `TASK_VM_INFO_COUNT` and `TASK_VM_INFO_REV1_COUNT` macros are too  
    // complex for the Swift C importer, so we have to define them ourselves.  
    let TASK_VM_INFO_COUNT = mach_msg_type_number_t(MemoryLayout<task_vm_info_data_t>.size / MemoryLayout<integer_t>.size)  
    let TASK_VM_INFO_REV1_COUNT = mach_msg_type_number_t(MemoryLayout.offset(of: \task_vm_info_data_t.min_address)! / MemoryLayout<integer_t>.size)  
    var info = task_vm_info_data_t()  
    var count = TASK_VM_INFO_COUNT  
    let kr = withUnsafeMutablePointer(to: &info) { infoPtr in  
        infoPtr.withMemoryRebound(to: integer_t.self, capacity: Int(count)) { intPtr in  
            task_info(mach_task_self_, task_flavor_t(TASK_VM_INFO), intPtr, &count)  
        }  
    }  
    guard  
        kr == KERN_SUCCESS,  
        count >= TASK_VM_INFO_REV1_COUNT  
    else { return nil }  
    return info.phys_footprint  
}  

稍微修改一下以创建类级别的 Swift 方法集，可以轻松返回实际字节和格式化输出（以 MB 为单位）以供显示。我将其用作自动化 UITest 套件的一部分，以记录同一测试的多次迭代前后使用的内存，以查看是否有任何潜在的泄漏或分配需要调查。

//  Created by Alex Zavatone on 8/1/19.
//

class Memory: NSObject {

    // From Quinn the Eskimo at Apple.
    // https://forums.developer.apple.com/thread/105088#357415

    class func memoryFootprint() -> Float? {
        // The `TASK_VM_INFO_COUNT` and `TASK_VM_INFO_REV1_COUNT` macros are too
        // complex for the Swift C importer, so we have to define them ourselves.
        let TASK_VM_INFO_COUNT = mach_msg_type_number_t(MemoryLayout<task_vm_info_data_t>.size / MemoryLayout<integer_t>.size)
        let TASK_VM_INFO_REV1_COUNT = mach_msg_type_number_t(MemoryLayout.offset(of: \task_vm_info_data_t.min_address)! / MemoryLayout<integer_t>.size)
        var info = task_vm_info_data_t()
        var count = TASK_VM_INFO_COUNT
        let kr = withUnsafeMutablePointer(to: &info) { infoPtr in
            infoPtr.withMemoryRebound(to: integer_t.self, capacity: Int(count)) { intPtr in
                task_info(mach_task_self_, task_flavor_t(TASK_VM_INFO), intPtr, &count)
            }
        }
        guard
            kr == KERN_SUCCESS,
            count >= TASK_VM_INFO_REV1_COUNT
            else { return nil }
        
        let usedBytes = Float(info.phys_footprint)
        return usedBytes
    }
    
    class func formattedMemoryFootprint() -> String
    {
        let usedBytes: UInt64? = UInt64(self.memoryFootprint() ?? 0)
        let usedMB = Double(usedBytes ?? 0) / 1024 / 1024
        let usedMBAsString: String = "\(usedMB)MB"
        return usedMBAsString
     }
}

享受吧！

注意：有进取心的编码员可能希望向类添加静态格式化程序，以便usedMBAsString 仅返回 2 个有效小数位。

Answer 8

Objective-C version:

size_t memoryFootprint()
{
    task_vm_info_data_t vmInfo;
    mach_msg_type_number_t count = TASK_VM_INFO_COUNT;
    kern_return_t result = task_info(mach_task_self(), TASK_VM_INFO, (task_info_t) &vmInfo, &count);
    if (result != KERN_SUCCESS)
        return 0;
    return static_cast<size_t>(vmInfo.phys_footprint);
}