Forums - Understanding count of logical processing units in Qualcomm Robotics SOC

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Understanding count of logical processing units in Qualcomm Robotics SOC
rajsingh132323
Join Date: 3 Aug 23
Posts: 1
Posted: Thu, 2023-08-03 00:10

I have Qualcomm RB5 board.

Its SOC spec sheet says following:

CPU: Kryo 585 CPU, 64-bit, up to 2.84 GHz
ISP: Qualcomm Spectra 480 ISP with Dual 14-bit image  signal processing
GPU Adreno 650 GPU w/ support for Open GL ES & Open CL

Product brief link

The lscpu output is as follows:

$ lscpu
Architecture:                    aarch64
CPU op-mode(s):                  32-bit, 64-bit
Byte Order:                      Little Endian
CPU(s):                          8
On-line CPU(s) list:             0-7
Thread(s) per core:              1
Core(s) per socket:              2
Socket(s):                       3
Vendor ID:                       Qualcomm
Model:                           14
Stepping:                        0xd
CPU max MHz:                     2841.6001
CPU min MHz:                     300.0000
BogoMIPS:                        38.40
Vulnerability Itlb multihit:     Not affected
Vulnerability L1tf:              Not affected
Vulnerability Mds:               Not affected
Vulnerability Meltdown:          Vulnerable
Vulnerability Mmio stale data:   Not affected
Vulnerability Retbleed:          Not affected
Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled v
                                 ia prctl
Vulnerability Spectre v1:        Mitigation; __user pointer sanitization
Vulnerability Spectre v2:        Mitigation; CSV2, BHB
Vulnerability Srbds:             Not affected
Vulnerability Tsx async abort:   Not affected
Flags:                           fp asimd evtstrm aes pmull sha1 sha2 crc32 atom
                                 ics fphp asimdhp cpuid asimdrdm lrcpc dcpop asi
                                 mddp

I want to understand meaning of following:

CPU(s):                          8
On-line CPU(s) list:             0-7
Thread(s) per core:              1
Core(s) per socket:              2
Socket(s):                       3

I know this is 8 core processor. But I have following questions:

  1. By  CPU(s): 8, does it mean it has 8 cores?
  2. Socket * Cores per socket = 3 * 2 = 6. Why it differs from 8?
  3. Does this mean that total number of logical cores = 3 * 2 * 8 = 48?
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avik.de
Join Date: 26 Oct 23
Posts: 3
Posted: Thu, 2023-12-07 06:53

It has 8 cores

CPU 0-3 = Kryo silver @ 1.81GHz, 4-6 = Gold @ 2.42GHz, 7 = Gold Prime @ 2.84 GHz

You can use `cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq` and other files in there to see the current and max frequencies per core.

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