memstat HeapInuse and TotalAlloc need explain

huangapple
go评论116阅读模式
英文:

memstat HeapInuse and TotalAlloc need explain

问题

我想要转储Golang的内存统计信息。

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"github.com/dustin/go-humanize"
  6. 	"runtime"
  7. 	"time"
  8. )
  10. func main() {
  11. 	for {
  12. 		var mem = new(runtime.MemStats)
  13. 		runtime.ReadMemStats(mem)
  14. 		fmt.Println("HeapInuse:", humanize.Bytes(mem.HeapInuse), "TotalAlloc:", humanize.Bytes(mem.TotalAlloc))
  16. 		allocate()
  17. 		time.Sleep(100 * time.Millisecond)
  18. 	}
  20. }
  22. func allocate() {
  23. 	//  0.25MB
  24. 	_ = make([]byte, int((1<<20)*0.25))
  25. }

当我转储内存信息时，我发现HeapInuse比TotalAlloc大？但我不明白原因。我认为TotalAlloc应该包括HeapInuse。

英文:

i want dump golang memstat

  1. package main
  3. import (
  4. 	&quot;fmt&quot;
  5. 	&quot;github.com/dustin/go-humanize&quot;
  6. 	&quot;runtime&quot;
  7. 	&quot;time&quot;
  8. )
  10. func main() {
  11. 	for {
  12. 		var mem = new(runtime.MemStats)
  13. 		runtime.ReadMemStats(mem)
  14. 		fmt.Println(&quot;HeapInuse:&quot;, humanize.Bytes(mem.HeapInuse), &quot;TotalAlloc:&quot;, humanize.Bytes(mem.TotalAlloc))
  16. 		allocate()
  17. 		time.Sleep(100 * time.Millisecond)
  18. 	}
  20. }
  22. func allocate() {
  23. 	//  0.25MB
  24. 	_ = make([]byte, int((1&lt;&lt;20)*0.25))
  25. }

when i dump the mem info

  1. HeapInuse: 418 kB TotalAlloc: 154 kB ? why  HeapInuse bigger than TotalAlloc
  2. HeapInuse: 688 kB TotalAlloc: 417 kB
  3. HeapInuse: 950 kB TotalAlloc: 680 kB
  4. HeapInuse: 1.2 MB TotalAlloc: 942 kB
  5. HeapInuse: 1.5 MB TotalAlloc: 1.2 MB
  6. HeapInuse: 1.8 MB TotalAlloc: 1.5 MB
  7. HeapInuse: 2.0 MB TotalAlloc: 1.7 MB
  8. HeapInuse: 2.3 MB TotalAlloc: 2.0 MB
  9. HeapInuse: 2.5 MB TotalAlloc: 2.3 MB
  10. HeapInuse: 2.8 MB TotalAlloc: 2.5 MB
  11. HeapInuse: 3.1 MB TotalAlloc: 2.8 MB
  12. HeapInuse: 3.3 MB TotalAlloc: 3.0 MB
  13. HeapInuse: 3.6 MB TotalAlloc: 3.3 MB
  14. HeapInuse: 3.9 MB TotalAlloc: 3.6 MB
  15. HeapInuse: 4.1 MB TotalAlloc: 3.8 MB
  16. HeapInuse: 4.4 MB TotalAlloc: 4.1 MB
  17. HeapInuse: 410 kB TotalAlloc: 4.4 MB

i found HeapInuse bigger than TotalAlloc? but i cannt understand reason ? i think the totalAlloc should include HeapInuse.

答案1

得分: 2

让我们阅读下面的官方评论：

TotalAlloc

// TotalAlloc 是分配给堆对象的累积字节数。
//
// TotalAlloc 在分配堆对象时增加，但与 Alloc 和 HeapAlloc 不同，
// 当对象被释放时，它不会减少。
TotalAlloc uint64

HeapInuse

// HeapInuse 是正在使用的字节数。
//
// 正在使用的 span 至少包含一个对象。这些 span
// 只能用于大致相同大小的其他对象。
//
// HeapInuse 减去 HeapAlloc 估计了已经分配给特定大小类别的内存量，
// 但目前未被使用。这是碎片化的上限，但通常可以高效地重用这些内存。
HeapInuse uint64

  • HeapInuse 是分配给堆的内存（来自操作系统），可能未被对象使用
  • TotalAlloc 是为堆对象分配的内存

让我们尝试 HeapAlloc

// HeapAlloc 是分配的堆对象的字节数。
//
// “已分配”的堆对象包括所有可达对象，以及垃圾收集器尚未释放的不可达对象。
// 具体而言，HeapAlloc 在分配堆对象时增加，在堆被扫描并释放不可达对象时减少。
// 扫描在 GC 循环之间逐步进行，因此这两个过程同时进行，
// 结果是 HeapAlloc 倾向于平滑变化（与停止-全局垃圾收集器的锯齿形相反）。
HeapAlloc uint64

结果

HeapAlloc: 148 kB HeapInuse: 401 kB TotalAlloc: 148 kB
HeapAlloc: 412 kB HeapInuse: 664 kB TotalAlloc: 412 kB
HeapAlloc: 675 kB HeapInuse: 926 kB TotalAlloc: 675 kB
HeapAlloc: 937 kB HeapInuse: 1.2 MB TotalAlloc: 937 kB
HeapAlloc: 1.2 MB HeapInuse: 1.5 MB TotalAlloc: 1.2 MB
HeapAlloc: 1.5 MB HeapInuse: 1.7 MB TotalAlloc: 1.5 MB
HeapAlloc: 1.7 MB HeapInuse: 2.0 MB TotalAlloc: 1.7 MB
HeapAlloc: 2.0 MB HeapInuse: 2.2 MB TotalAlloc: 2.0 MB
HeapAlloc: 2.2 MB HeapInuse: 2.5 MB TotalAlloc: 2.2 MB
HeapAlloc: 2.5 MB HeapInuse: 2.8 MB TotalAlloc: 2.5 MB
HeapAlloc: 2.8 MB HeapInuse: 3.0 MB TotalAlloc: 2.8 MB
HeapAlloc: 3.0 MB HeapInuse: 3.3 MB TotalAlloc: 3.0 MB
HeapAlloc: 3.3 MB HeapInuse: 3.6 MB TotalAlloc: 3.3 MB
HeapAlloc: 3.6 MB HeapInuse: 3.8 MB TotalAlloc: 3.6 MB
HeapAlloc: 3.8 MB HeapInuse: 4.1 MB TotalAlloc: 3.8 MB
HeapAlloc: 4.1 MB HeapInuse: 4.3 MB TotalAlloc: 4.1 MB
HeapAlloc: 134 kB HeapInuse: 393 kB TotalAlloc: 4.4 MB
HeapAlloc: 398 kB HeapInuse: 664 kB TotalAlloc: 4.6 MB
HeapAlloc: 660 kB HeapInuse: 926 kB TotalAlloc: 4.9 MB
HeapAlloc: 923 kB HeapInuse: 1.2 MB TotalAlloc: 5.1 MB
HeapAlloc: 1.2 MB HeapInuse: 1.4 MB TotalAlloc: 5.4 MB
HeapAlloc: 1.4 MB HeapInuse: 1.7 MB TotalAlloc: 5.7 MB
HeapAlloc: 1.7 MB HeapInuse: 2.0 MB TotalAlloc: 5.9 MB
HeapAlloc: 2.0 MB HeapInuse: 2.2 MB TotalAlloc: 6.2 MB
HeapAlloc: 2.2 MB HeapInuse: 2.5 MB TotalAlloc: 6.5 MB
HeapAlloc: 2.5 MB HeapInuse: 2.8 MB TotalAlloc: 6.7 MB
HeapAlloc: 2.8 MB HeapInuse: 3.0 MB TotalAlloc: 7.0 MB
HeapAlloc: 3.0 MB HeapInuse: 3.3 MB TotalAlloc: 7.2 MB
HeapAlloc: 3.3 MB HeapInuse: 3.5 MB TotalAlloc: 7.5 MB
HeapAlloc: 3.5 MB HeapInuse: 3.8 MB TotalAlloc: 7.8 MB
HeapAlloc: 3.8 MB HeapInuse: 4.1 MB TotalAlloc: 8.0 MB
HeapAlloc: 4.1 MB HeapInuse: 4.3 MB TotalAlloc: 8.3 MB
HeapAlloc: 136 kB HeapInuse: 401 kB TotalAlloc: 8.6 MB
HeapAlloc: 400 kB HeapInuse: 664 kB TotalAlloc: 8.8 MB
HeapAlloc: 662 kB HeapInuse: 926 kB TotalAlloc: 9.1 MB
HeapAlloc: 924 kB HeapInuse: 1.2 MB TotalAlloc: 9.3 MB
HeapAlloc: 1.2 MB HeapInuse: 1.4 MB TotalAlloc: 9.6 MB
HeapAlloc: 1.4 MB HeapInuse: 1.7 MB TotalAlloc: 9.9 MB
HeapAlloc: 1.7 MB HeapInuse: 2.0 MB TotalAlloc: 10 MB
HeapAlloc: 2.0 MB HeapInuse: 2.2 MB TotalAlloc: 10 MB
HeapAlloc: 2.2 MB HeapInuse: 2.5 MB TotalAlloc: 11 MB
HeapAlloc: 2.5 MB HeapInuse: 2.8 MB TotalAlloc: 11 MB
HeapAlloc: 2.8 MB HeapInuse: 3.0 MB TotalAlloc: 11 MB
HeapAlloc: 3.0 MB HeapInuse: 3.3 MB TotalAlloc: 11 MB
HeapAlloc: 3.3 MB HeapInuse: 3.5 MB TotalAlloc: 12 MB
HeapAlloc: 3.5 MB HeapInuse: 3.8 MB TotalAlloc: 12 MB
HeapAlloc: 3.8 MB HeapInuse: 4.1 MB TotalAlloc: 12 MB
HeapAlloc: 4.1 MB HeapInuse: 4.3 MB TotalAlloc: 12 MB
HeapAlloc: 136 kB HeapInuse: 401 kB TotalAlloc: 13 MB
HeapAlloc: 400 kB HeapInuse: 664 kB TotalAlloc: 13 MB
HeapAlloc: 663 kB HeapInuse: 926 kB TotalAlloc: 13 MB
HeapAlloc: 925 kB HeapInuse: 1.2 MB TotalAlloc: 14 MB
HeapAlloc: 1.2 MB HeapInuse: 1.4 MB TotalAlloc: 14 MB
HeapAlloc: 1.4 MB HeapInuse: 1.7 MB TotalAlloc: 14 MB

英文:

Let's read the official comments below:

TotalAlloc

  1. // TotalAlloc is cumulative bytes allocated for heap objects.
  2. //
  3. // TotalAlloc increases as heap objects are allocated, but
  4. // unlike Alloc and HeapAlloc, it does not decrease when
  5. // objects are freed.
  6. TotalAlloc uint64

HeapInuse

  1. // HeapInuse is bytes in in-use spans.
  2. //
  3. // In-use spans have at least one object in them. These spans
  4. // can only be used for other objects of roughly the same
  5. // size.
  6. //
  7. // HeapInuse minus HeapAlloc estimates the amount of memory
  8. // that has been dedicated to particular size classes, but is
  9. // not currently being used. This is an upper bound on
  10. // fragmentation, but in general this memory can be reused
  11. // efficiently.
  12. HeapInuse uint64
  • HeapInuse is memory allocated (from the OS), may not be used by objects
  • TotalAlloc is memory allocated for heap objects

Let's try HeapAlloc

  1. // HeapAlloc is bytes of allocated heap objects.
  2. //
  3. // &quot;Allocated&quot; heap objects include all reachable objects, as
  4. // well as unreachable objects that the garbage collector has
  5. // not yet freed. Specifically, HeapAlloc increases as heap
  6. // objects are allocated and decreases as the heap is swept
  7. // and unreachable objects are freed. Sweeping occurs
  8. // incrementally between GC cycles, so these two processes
  9. // occur simultaneously, and as a result HeapAlloc tends to
  10. // change smoothly (in contrast with the sawtooth that is
  11. // typical of stop-the-world garbage collectors).
  12. HeapAlloc uint64

Result

  1. HeapAlloc: 148 kB HeapInuse: 401 kB TotalAlloc: 148 kB
  2. HeapAlloc: 412 kB HeapInuse: 664 kB TotalAlloc: 412 kB
  3. HeapAlloc: 675 kB HeapInuse: 926 kB TotalAlloc: 675 kB
  4. HeapAlloc: 937 kB HeapInuse: 1.2 MB TotalAlloc: 937 kB
  5. HeapAlloc: 1.2 MB HeapInuse: 1.5 MB TotalAlloc: 1.2 MB
  6. HeapAlloc: 1.5 MB HeapInuse: 1.7 MB TotalAlloc: 1.5 MB
  7. HeapAlloc: 1.7 MB HeapInuse: 2.0 MB TotalAlloc: 1.7 MB
  8. HeapAlloc: 2.0 MB HeapInuse: 2.2 MB TotalAlloc: 2.0 MB
  9. HeapAlloc: 2.2 MB HeapInuse: 2.5 MB TotalAlloc: 2.2 MB
  10. HeapAlloc: 2.5 MB HeapInuse: 2.8 MB TotalAlloc: 2.5 MB
  11. HeapAlloc: 2.8 MB HeapInuse: 3.0 MB TotalAlloc: 2.8 MB
  12. HeapAlloc: 3.0 MB HeapInuse: 3.3 MB TotalAlloc: 3.0 MB
  13. HeapAlloc: 3.3 MB HeapInuse: 3.6 MB TotalAlloc: 3.3 MB
  14. HeapAlloc: 3.6 MB HeapInuse: 3.8 MB TotalAlloc: 3.6 MB
  15. HeapAlloc: 3.8 MB HeapInuse: 4.1 MB TotalAlloc: 3.8 MB
  16. HeapAlloc: 4.1 MB HeapInuse: 4.3 MB TotalAlloc: 4.1 MB
  17. HeapAlloc: 134 kB HeapInuse: 393 kB TotalAlloc: 4.4 MB
  18. HeapAlloc: 398 kB HeapInuse: 664 kB TotalAlloc: 4.6 MB
  19. HeapAlloc: 660 kB HeapInuse: 926 kB TotalAlloc: 4.9 MB
  20. HeapAlloc: 923 kB HeapInuse: 1.2 MB TotalAlloc: 5.1 MB
  21. HeapAlloc: 1.2 MB HeapInuse: 1.4 MB TotalAlloc: 5.4 MB
  22. HeapAlloc: 1.4 MB HeapInuse: 1.7 MB TotalAlloc: 5.7 MB
  23. HeapAlloc: 1.7 MB HeapInuse: 2.0 MB TotalAlloc: 5.9 MB
  24. HeapAlloc: 2.0 MB HeapInuse: 2.2 MB TotalAlloc: 6.2 MB
  25. HeapAlloc: 2.2 MB HeapInuse: 2.5 MB TotalAlloc: 6.5 MB
  26. HeapAlloc: 2.5 MB HeapInuse: 2.8 MB TotalAlloc: 6.7 MB
  27. HeapAlloc: 2.8 MB HeapInuse: 3.0 MB TotalAlloc: 7.0 MB
  28. HeapAlloc: 3.0 MB HeapInuse: 3.3 MB TotalAlloc: 7.2 MB
  29. HeapAlloc: 3.3 MB HeapInuse: 3.5 MB TotalAlloc: 7.5 MB
  30. HeapAlloc: 3.5 MB HeapInuse: 3.8 MB TotalAlloc: 7.8 MB
  31. HeapAlloc: 3.8 MB HeapInuse: 4.1 MB TotalAlloc: 8.0 MB
  32. HeapAlloc: 4.1 MB HeapInuse: 4.3 MB TotalAlloc: 8.3 MB
  33. HeapAlloc: 136 kB HeapInuse: 401 kB TotalAlloc: 8.6 MB
  34. HeapAlloc: 400 kB HeapInuse: 664 kB TotalAlloc: 8.8 MB
  35. HeapAlloc: 662 kB HeapInuse: 926 kB TotalAlloc: 9.1 MB
  36. HeapAlloc: 924 kB HeapInuse: 1.2 MB TotalAlloc: 9.3 MB
  37. HeapAlloc: 1.2 MB HeapInuse: 1.4 MB TotalAlloc: 9.6 MB
  38. HeapAlloc: 1.4 MB HeapInuse: 1.7 MB TotalAlloc: 9.9 MB
  39. HeapAlloc: 1.7 MB HeapInuse: 2.0 MB TotalAlloc: 10 MB
  40. HeapAlloc: 2.0 MB HeapInuse: 2.2 MB TotalAlloc: 10 MB
  41. HeapAlloc: 2.2 MB HeapInuse: 2.5 MB TotalAlloc: 11 MB
  42. HeapAlloc: 2.5 MB HeapInuse: 2.8 MB TotalAlloc: 11 MB
  43. HeapAlloc: 2.8 MB HeapInuse: 3.0 MB TotalAlloc: 11 MB
  44. HeapAlloc: 3.0 MB HeapInuse: 3.3 MB TotalAlloc: 11 MB
  45. HeapAlloc: 3.3 MB HeapInuse: 3.5 MB TotalAlloc: 12 MB
  46. HeapAlloc: 3.5 MB HeapInuse: 3.8 MB TotalAlloc: 12 MB
  47. HeapAlloc: 3.8 MB HeapInuse: 4.1 MB TotalAlloc: 12 MB
  48. HeapAlloc: 4.1 MB HeapInuse: 4.3 MB TotalAlloc: 12 MB
  49. HeapAlloc: 136 kB HeapInuse: 401 kB TotalAlloc: 13 MB
  50. HeapAlloc: 400 kB HeapInuse: 664 kB TotalAlloc: 13 MB
  51. HeapAlloc: 663 kB HeapInuse: 926 kB TotalAlloc: 13 MB
  52. HeapAlloc: 925 kB HeapInuse: 1.2 MB TotalAlloc: 14 MB
  53. HeapAlloc: 1.2 MB HeapInuse: 1.4 MB TotalAlloc: 14 MB
  54. HeapAlloc: 1.4 MB HeapInuse: 1.7 MB TotalAlloc: 14 MB

huangapple
  • 本文由 发表于 2022年2月9日 14:46:35
  • 转载请务必保留本文链接：https://go.coder-hub.com/71045082.html
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