4 ms·

A vCPU is a logical core, not a physical core. So yes, based on HT.

by douglasfshearer 8y ago

mamon 8y ago
Still EPYC processors have up to 32 cores, 64 HT - where is 96 comming from?
- douglasfshearer 8y ago
  Two sockets.
- pdpi 8y ago
  They're not necessarily using 32 core chips. That could just as easily be a 2x24 board.
  - _msw_ 8y ago
    Hi, a developer on the EC2 team here: the underlying CPU topology, in terms of which logical processors share L3 caches (i.e., which CPUs are part of the same CCX [1]) is provided to the instance's operating system through ACPI tables and CPUID values. The m5a.24xlarge and r5a.24xlarge instances show two sockets, six NUMA nodes, and 12 L3 cache slices. [ec2-user@ip-10-0-0-120 ~]$ likwid-topology [...] -------------------------------------------------------------------------------- Socket 0: ( 0 48 1 49 2 50 3 51 4 52 5 53 6 54 7 55 8 56 9 57 10 58 11 59 12 60 13 61 14 62 15 63 16 64 17 65 18 66 19 67 20 68 21 69 22 70 23 71 ) Socket 1: ( 24 72 25 73 26 74 27 75 28 76 29 77 30 78 31 79 32 80 33 81 34 82 35 83 36 84 37 85 38 86 39 87 40 88 41 89 42 90 43 91 44 92 45 93 46 94 47 95 ) -------------------------------------------------------------------------------- ******************************************************************************** Cache Topology ******************************************************************************** Level: 1 Size: 32 kB Cache groups: ( 0 48 ) ( 1 49 ) ( 2 50 ) ( 3 51 ) ( 4 52 ) ( 5 53 ) ( 6 54 ) ( 7 55 ) ( 8 56 ) ( 9 57 ) ( 10 58 ) ( 11 59 ) ( 12 60 ) ( 13 61 ) ( 14 62 ) ( 15 63 ) ( 16 64 ) ( 17 65 ) ( 18 66 ) ( 19 67 ) ( 20 68 ) ( 21 69 ) ( 22 70 ) ( 23 71 ) ( 24 72 ) ( 25 73 ) ( 26 74 ) ( 27 75 ) ( 28 76 ) ( 29 77 ) ( 30 78 ) ( 31 79 ) ( 32 80 ) ( 33 81 ) ( 34 82 ) ( 35 83 ) ( 36 84 ) ( 37 85 ) ( 38 86 ) ( 39 87 ) ( 40 88 ) ( 41 89 ) ( 42 90 ) ( 43 91 ) ( 44 92 ) ( 45 93 ) ( 46 94 ) ( 47 95 ) -------------------------------------------------------------------------------- Level: 2 Size: 512 kB Cache groups: ( 0 48 ) ( 1 49 ) ( 2 50 ) ( 3 51 ) ( 4 52 ) ( 5 53 ) ( 6 54 ) ( 7 55 ) ( 8 56 ) ( 9 57 ) ( 10 58 ) ( 11 59 ) ( 12 60 ) ( 13 61 ) ( 14 62 ) ( 15 63 ) ( 16 64 ) ( 17 65 ) ( 18 66 ) ( 19 67 ) ( 20 68 ) ( 21 69 ) ( 22 70 ) ( 23 71 ) ( 24 72 ) ( 25 73 ) ( 26 74 ) ( 27 75 ) ( 28 76 ) ( 29 77 ) ( 30 78 ) ( 31 79 ) ( 32 80 ) ( 33 81 ) ( 34 82 ) ( 35 83 ) ( 36 84 ) ( 37 85 ) ( 38 86 ) ( 39 87 ) ( 40 88 ) ( 41 89 ) ( 42 90 ) ( 43 91 ) ( 44 92 ) ( 45 93 ) ( 46 94 ) ( 47 95 ) -------------------------------------------------------------------------------- Level: 3 Size: 8 MB Cache groups: ( 0 48 1 49 2 50 3 51 ) ( 4 52 5 53 6 54 7 55 ) ( 8 56 9 57 10 58 11 59 ) ( 12 60 13 61 14 62 15 63 ) ( 16 64 17 65 18 66 19 67 ) ( 20 68 21 69 22 70 23 71 ) ( 24 72 25 73 26 74 27 75 ) ( 28 76 29 77 30 78 31 79 ) ( 32 80 33 81 34 82 35 83 ) ( 36 84 37 85 38 86 39 87 ) ( 40 88 41 89 42 90 43 91 ) ( 44 92 45 93 46 94 47 95 ) -------------------------------------------------------------------------------- ******************************************************************************** NUMA Topology ******************************************************************************** NUMA domains: 6 -------------------------------------------------------------------------------- Domain: 0 Processors: ( 0 48 1 49 2 50 3 51 4 52 5 53 6 54 7 55 ) Distances: 10 16 16 32 32 32 Free memory: 63028.4 MB Total memory: 63291.6 MB -------------------------------------------------------------------------------- Domain: 1 Processors: ( 8 56 9 57 10 58 11 59 12 60 13 61 14 62 15 63 ) Distances: 16 10 16 32 32 32 Free memory: 63202.6 MB Total memory: 63375.1 MB -------------------------------------------------------------------------------- Domain: 2 Processors: ( 16 64 17 65 18 66 19 67 20 68 21 69 22 70 23 71 ) Distances: 16 16 10 32 32 32 Free memory: 63171.3 MB Total memory: 63375.1 MB -------------------------------------------------------------------------------- Domain: 3 Processors: ( 24 72 25 73 26 74 27 75 28 76 29 77 30 78 31 79 ) Distances: 32 32 32 10 16 16 Free memory: 63322.8 MB Total memory: 63375.1 MB -------------------------------------------------------------------------------- Domain: 4 Processors: ( 32 80 33 81 34 82 35 83 36 84 37 85 38 86 39 87 ) Distances: 32 32 32 16 10 16 Free memory: 63318.7 MB Total memory: 63375.1 MB -------------------------------------------------------------------------------- Domain: 5 Processors: ( 40 88 41 89 42 90 43 91 44 92 45 93 46 94 47 95 ) Distances: 32 32 32 16 16 10 Free memory: 63317.7 MB Total memory: 63374.1 MB -------------------------------------------------------------------------------- [1] https://en.wikichip.org/wiki/amd/microarchitectures/zen#CPU_Complex_.28CCX.29 https://en.wikichip.org/wiki/amd/microarchitectures/zen#CPU_...
    - mkbosmans 8y ago
      Can you share more details about this CPU? The page mentions a custom AMD EPYC, and indeed, your topology suggests this is not a standard 24-core CPU. A standard 24-core EPYC would have 3 enabled cores per CCX and 4 zeppelins (NUMA nodes) per CPU.
- neuromancer2701 8y ago
  The "Rome" EPYC processors have 64 cores and 128 threads and with a dual processor board you can have 128 cores 256 threads in a 1U server.
  - mattashii 8y ago
    SuperMicro has systems with 2 dual-socket systems in a 1u form factor[0], so 256c/512t per rack unit is not that far fetched. [0] For intel scalable: https://www.supermicro.com/products/system/1U/1029/SYS-1029TP-DTR.cfm https://www.supermicro.com/products/system/1U/1029/SYS-1029T...
    - shiftpgdn 8y ago
      That's just 2 servers with a shared backplane.

A vCPU is a logical core, not a physical core. So yes, based on HT.

mamon 8y ago

Still EPYC processors have up to 32 cores, 64 HT - where is 96 comming from?

douglasfshearer 8y ago
Two sockets.
pdpi 8y ago
They're not necessarily using 32 core chips. That could just as easily be a 2x24 board.
- _msw_ 8y ago
  Hi, a developer on the EC2 team here: the underlying CPU topology, in terms of which logical processors share L3 caches (i.e., which CPUs are part of the same CCX [1]) is provided to the instance's operating system through ACPI tables and CPUID values. The m5a.24xlarge and r5a.24xlarge instances show two sockets, six NUMA nodes, and 12 L3 cache slices. [ec2-user@ip-10-0-0-120 ~]$ likwid-topology [...] -------------------------------------------------------------------------------- Socket 0: ( 0 48 1 49 2 50 3 51 4 52 5 53 6 54 7 55 8 56 9 57 10 58 11 59 12 60 13 61 14 62 15 63 16 64 17 65 18 66 19 67 20 68 21 69 22 70 23 71 ) Socket 1: ( 24 72 25 73 26 74 27 75 28 76 29 77 30 78 31 79 32 80 33 81 34 82 35 83 36 84 37 85 38 86 39 87 40 88 41 89 42 90 43 91 44 92 45 93 46 94 47 95 ) -------------------------------------------------------------------------------- ******************************************************************************** Cache Topology ******************************************************************************** Level: 1 Size: 32 kB Cache groups: ( 0 48 ) ( 1 49 ) ( 2 50 ) ( 3 51 ) ( 4 52 ) ( 5 53 ) ( 6 54 ) ( 7 55 ) ( 8 56 ) ( 9 57 ) ( 10 58 ) ( 11 59 ) ( 12 60 ) ( 13 61 ) ( 14 62 ) ( 15 63 ) ( 16 64 ) ( 17 65 ) ( 18 66 ) ( 19 67 ) ( 20 68 ) ( 21 69 ) ( 22 70 ) ( 23 71 ) ( 24 72 ) ( 25 73 ) ( 26 74 ) ( 27 75 ) ( 28 76 ) ( 29 77 ) ( 30 78 ) ( 31 79 ) ( 32 80 ) ( 33 81 ) ( 34 82 ) ( 35 83 ) ( 36 84 ) ( 37 85 ) ( 38 86 ) ( 39 87 ) ( 40 88 ) ( 41 89 ) ( 42 90 ) ( 43 91 ) ( 44 92 ) ( 45 93 ) ( 46 94 ) ( 47 95 ) -------------------------------------------------------------------------------- Level: 2 Size: 512 kB Cache groups: ( 0 48 ) ( 1 49 ) ( 2 50 ) ( 3 51 ) ( 4 52 ) ( 5 53 ) ( 6 54 ) ( 7 55 ) ( 8 56 ) ( 9 57 ) ( 10 58 ) ( 11 59 ) ( 12 60 ) ( 13 61 ) ( 14 62 ) ( 15 63 ) ( 16 64 ) ( 17 65 ) ( 18 66 ) ( 19 67 ) ( 20 68 ) ( 21 69 ) ( 22 70 ) ( 23 71 ) ( 24 72 ) ( 25 73 ) ( 26 74 ) ( 27 75 ) ( 28 76 ) ( 29 77 ) ( 30 78 ) ( 31 79 ) ( 32 80 ) ( 33 81 ) ( 34 82 ) ( 35 83 ) ( 36 84 ) ( 37 85 ) ( 38 86 ) ( 39 87 ) ( 40 88 ) ( 41 89 ) ( 42 90 ) ( 43 91 ) ( 44 92 ) ( 45 93 ) ( 46 94 ) ( 47 95 ) -------------------------------------------------------------------------------- Level: 3 Size: 8 MB Cache groups: ( 0 48 1 49 2 50 3 51 ) ( 4 52 5 53 6 54 7 55 ) ( 8 56 9 57 10 58 11 59 ) ( 12 60 13 61 14 62 15 63 ) ( 16 64 17 65 18 66 19 67 ) ( 20 68 21 69 22 70 23 71 ) ( 24 72 25 73 26 74 27 75 ) ( 28 76 29 77 30 78 31 79 ) ( 32 80 33 81 34 82 35 83 ) ( 36 84 37 85 38 86 39 87 ) ( 40 88 41 89 42 90 43 91 ) ( 44 92 45 93 46 94 47 95 ) -------------------------------------------------------------------------------- ******************************************************************************** NUMA Topology ******************************************************************************** NUMA domains: 6 -------------------------------------------------------------------------------- Domain: 0 Processors: ( 0 48 1 49 2 50 3 51 4 52 5 53 6 54 7 55 ) Distances: 10 16 16 32 32 32 Free memory: 63028.4 MB Total memory: 63291.6 MB -------------------------------------------------------------------------------- Domain: 1 Processors: ( 8 56 9 57 10 58 11 59 12 60 13 61 14 62 15 63 ) Distances: 16 10 16 32 32 32 Free memory: 63202.6 MB Total memory: 63375.1 MB -------------------------------------------------------------------------------- Domain: 2 Processors: ( 16 64 17 65 18 66 19 67 20 68 21 69 22 70 23 71 ) Distances: 16 16 10 32 32 32 Free memory: 63171.3 MB Total memory: 63375.1 MB -------------------------------------------------------------------------------- Domain: 3 Processors: ( 24 72 25 73 26 74 27 75 28 76 29 77 30 78 31 79 ) Distances: 32 32 32 10 16 16 Free memory: 63322.8 MB Total memory: 63375.1 MB -------------------------------------------------------------------------------- Domain: 4 Processors: ( 32 80 33 81 34 82 35 83 36 84 37 85 38 86 39 87 ) Distances: 32 32 32 16 10 16 Free memory: 63318.7 MB Total memory: 63375.1 MB -------------------------------------------------------------------------------- Domain: 5 Processors: ( 40 88 41 89 42 90 43 91 44 92 45 93 46 94 47 95 ) Distances: 32 32 32 16 16 10 Free memory: 63317.7 MB Total memory: 63374.1 MB -------------------------------------------------------------------------------- [1] https://en.wikichip.org/wiki/amd/microarchitectures/zen#CPU_Complex_.28CCX.29 https://en.wikichip.org/wiki/amd/microarchitectures/zen#CPU_...
  - mkbosmans 8y ago
    Can you share more details about this CPU? The page mentions a custom AMD EPYC, and indeed, your topology suggests this is not a standard 24-core CPU. A standard 24-core EPYC would have 3 enabled cores per CCX and 4 zeppelins (NUMA nodes) per CPU.
neuromancer2701 8y ago
The "Rome" EPYC processors have 64 cores and 128 threads and with a dual processor board you can have 128 cores 256 threads in a 1U server.
- mattashii 8y ago
  SuperMicro has systems with 2 dual-socket systems in a 1u form factor[0], so 256c/512t per rack unit is not that far fetched. [0] For intel scalable: https://www.supermicro.com/products/system/1U/1029/SYS-1029TP-DTR.cfm https://www.supermicro.com/products/system/1U/1029/SYS-1029T...
  - shiftpgdn 8y ago
    That's just 2 servers with a shared backplane.