无法在我的计算机上找到有关TLB的任何信息，也无法获取有关TLB的硬件计数器的信息。

Question

我使用的Ubuntu版本是Ubuntu 18.04.6LTS，内核版本是5.4.0-148泛型。我的处理器是12th Gen (R) Core (商标) i7-12700。

我想知道不同页面大小(1G，2MB，4KB)在我的CPU中的TLB条目的数量，以及在程序执行过程中dTLB遗漏的数量。

cpuid -1命令告诉我它们是0：

    L1 TLB/cache information: 2M/4M pages & L1 TLB (0x80000005/eax):
      instruction # entries     = 0x0 (0)
      instruction associativity = 0x0 (0)
      data # entries            = 0x0 (0)
      data associativity        = 0x0 (0)
   L1 TLB/cache information: 4K pages & L1 TLB (0x80000005/ebx):
      instruction # entries     = 0x0 (0)
      instruction associativity = 0x0 (0)
      data # entries            = 0x0 (0)
      data associativity        = 0x0 (0)
   L1 data cache information (0x80000005/ecx):
      line size (bytes) = 0x0 (0)
      lines per tag     = 0x0 (0)
      associativity     = 0x0 (0)
      size (KB)         = 0x0 (0)
   L1 instruction cache information (0x80000005/edx):
      line size (bytes) = 0x0 (0)
      lines per tag     = 0x0 (0)
      associativity     = 0x0 (0)
      size (KB)         = 0x0 (0)
   L2 TLB/cache information: 2M/4M pages & L2 TLB (0x80000006/eax):
      instruction # entries     = 0x0 (0)
      instruction associativity = L2 off (0)
      data # entries            = 0x0 (0)
      data associativity        = L2 off (0)
   L2 TLB/cache information: 4K pages & L2 TLB (0x80000006/ebx):
      instruction # entries     = 0x0 (0)
      instruction associativity = L2 off (0)
      data # entries            = 0x0 (0)
      data associativity        = L2 off (0)
   L2 unified cache information (0x80000006/ecx):
      line size (bytes) = 0x40 (64)
      lines per tag     = 0x0 (0)
      associativity     = 0x7 (7)
      size (KB)         = 0x500 (1280)
   L3 cache information (0x80000006/edx):
      line size (bytes)     = 0x0 (0)
      lines per tag         = 0x0 (0)
      associativity         = L2 off (0)
      size (in 512KB units) = 0x0 (0)

不支持perf stat -e dTLB-loads,dTLB-load-misses,iTLB-load-misses显示

最新情况：

$ cpuid -1 -l 2
CPU:
      0xff: cache data is in CPUID 4
      0xfe: unknown
      0xf0: 64 byte prefetching

$ cpuid -1 -l 0x18
CPU:
   0x00000018 0x00: eax=0x00000004 ebx=0x00000000 ecx=0x00000000 edx=0x00000000

$ perf -v
perf version 5.4.231


$ perf list

List of pre-defined events (to be used in -e):

  branch-instructions OR branches                    [Hardware event]
  branch-misses                                      [Hardware event]
  bus-cycles                                         [Hardware event]
  cache-misses                                       [Hardware event]
  cache-references                                   [Hardware event]
  cpu-cycles OR cycles                               [Hardware event]
  instructions                                       [Hardware event]
  ref-cycles                                         [Hardware event]

  alignment-faults                                   [Software event]
  bpf-output                                         [Software event]
  context-switches OR cs                             [Software event]
  cpu-clock                                          [Software event]
  cpu-migrations OR migrations                       [Software event]
  dummy                                              [Software event]
  emulation-faults                                   [Software event]
  major-faults                                       [Software event]
  minor-faults                                       [Software event]
  page-faults OR faults                              [Software event]
  task-clock                                         [Software event]

我完全搞不懂我的机器出了什么问题。

Answer 1

我怀疑你的机器有什么问题。cpuid的S输出是原始的，需要一些解释；具体来说，对于TLB信息，你应该看看第2页的信息而不是您引用的部分。您将在输出中找到更高的值，或者直接请求它：

$ cpuid -1 -l 2
CPU:
      0x63: data TLB: 2M/4M pages, 4-way, 32 entries
            data TLB: 1G pages, 4-way, 4 entries
      0x03: data TLB: 4K pages, 4-way, 64 entries
      0x76: instruction TLB: 2M/4M pages, fully, 8 entries
      0xff: cache data is in CPUID leaf 4
      0xb5: instruction TLB: 4K, 8-way, 64 entries
      0xf0: 64 byte prefetching
      0xc1: L2 TLB: 4K/2M pages, 8-way, 1024 entries

就perf而言，您所拥有的版本可能不知道您的CPU (我还没有检查)。