Why do ioscan and sar/vmstat report different number of processors?

[RobUrban]

Hello Folks,

a customer has a PA-Risc system, model "9000/800/rp8420" running HP-UX 11v1 ("B.11.11").

"ioscan -kfnC processor" reports 32 processors:

Class       I  H/W Path  Driver    S/W State H/W Type  Description
===================================================================
processor   0  0/10      processor CLAIMED   PROCESSOR Processor
processor   1  0/11      processor CLAIMED   PROCESSOR Processor
processor   2  0/12      processor CLAIMED   PROCESSOR Processor
processor   3  0/13      processor CLAIMED   PROCESSOR Processor
processor   4  0/14      processor CLAIMED   PROCESSOR Processor
processor   5  0/15      processor CLAIMED   PROCESSOR Processor
processor   6  0/16      processor CLAIMED   PROCESSOR Processor
processor   7  0/17      processor CLAIMED   PROCESSOR Processor
processor   8  1/10      processor CLAIMED   PROCESSOR Processor
processor   9  1/11      processor CLAIMED   PROCESSOR Processor
processor  10  1/12      processor CLAIMED   PROCESSOR Processor
processor  11  1/13      processor CLAIMED   PROCESSOR Processor
processor  12  1/14      processor CLAIMED   PROCESSOR Processor
processor  13  1/15      processor CLAIMED   PROCESSOR Processor
processor  14  1/16      processor CLAIMED   PROCESSOR Processor
processor  15  1/17      processor CLAIMED   PROCESSOR Processor
processor  16  2/10      processor CLAIMED   PROCESSOR Processor
processor  17  2/11      processor CLAIMED   PROCESSOR Processor
processor  18  2/12      processor CLAIMED   PROCESSOR Processor
processor  19  2/13      processor CLAIMED   PROCESSOR Processor
processor  20  2/14      processor CLAIMED   PROCESSOR Processor
processor  21  2/15      processor CLAIMED   PROCESSOR Processor
processor  22  2/16      processor CLAIMED   PROCESSOR Processor
processor  23  2/17      processor CLAIMED   PROCESSOR Processor
processor  24  3/10      processor CLAIMED   PROCESSOR Processor
processor  25  3/11      processor CLAIMED   PROCESSOR Processor
processor  26  3/12      processor CLAIMED   PROCESSOR Processor
processor  27  3/13      processor CLAIMED   PROCESSOR Processor
processor  28  3/14      processor CLAIMED   PROCESSOR Processor
processor  29  3/15      processor CLAIMED   PROCESSOR Processor
processor  30  3/16      processor CLAIMED   PROCESSOR Processor
processor  31  3/17      processor CLAIMED   PROCESSOR Processor

"print_manifest" also reports 32 processors:

System Hardware

    Model:              9000/800/rp8420    
    Main Memory:        98253 MB
    Processors:         32
    OS mode:            64 bit

However, sar and vmstat only show metrics for 16 processors. Here is one sample of  "sar -AM 5 999" output:

HP-UX myhostname B.11.11 U 9000/800    10/18/22

09:57:02     cpu    %usr    %sys    %wio   %idle
           device   %busy   avque   r+w/s  blks/s  avwait  avserv
             cpu runq-sz %runocc swpq-sz %swpocc
         bread/s lread/s %rcache bwrit/s lwrit/s %wcache pread/s pwrit/s
         swpin/s bswin/s swpot/s bswot/s pswch/s
         scall/s  sread/s  swrit/s   fork/s   exec/s  rchar/s  wchar/s
          iget/s namei/s dirbk/s
         rawch/s canch/s outch/s rcvin/s xmtin/s mdmin/s
         text-sz  ov  proc-sz  ov  inod-sz  ov  file-sz  ov 
           msg/s  sema/s
09:57:07       0       1       1       0      98
               2       0       1       0      99
               4       0       1       0      99
               6       0       0       0      99
               8       5       7       3      85
              10       0       0       0     100
              12       0       1       0      98
              14       0       0       0     100
              16       0       1       0      99
              18       0       1       0      99
              20       0       1       1      98
              22       1      23       1      75
              24       2       1       5      92
              26       1       1       0      98
              28       1       3       0      96
              30       0       2       2      96
          system       1       3       1      96
           c2t6d0   11.53    0.52      25     451    0.15    9.78
           c6t6d0    0.80    0.50       2      13    0.00    6.41
           c4t6d0    0.20    0.50       1      10    0.00    3.88
           c0t6d0    6.96    0.50      20     430    0.04    5.58
               0     0.0       0
               2     0.0       0
               4     0.0       0
               6     0.0       0
               8     0.0       0
              10     0.0       0
              12     0.0       0
              14     0.0       0
              16     0.0       0
              18     0.0       0
              20     0.0       0
              22     0.0       0
              24     0.0       0
              26     0.0       0
              28     0.0       0
              30     0.0       0
          system     0.0       0     0.0       0
               0    3905     100      28     554      95       0       0
            0.00     0.0    0.00     0.0    1626
           30148     1255      523    17.30    17.10  32274932   266891
               3     858       0
               0       0       0       0       0       0
           N/A   N/A 228/4096  0  2850/63488 0  2294/63498 0
            0.00    0.00

and one "vmstat -n 5 999" sample:

VM
       memory                     page                          faults
     avm    free   re   at    pi   po    fr   de    sr     in     sy    cs  
  597036  17716240  400   82     0    0     0    0     0  11492  24999  2531
CPU
    cpu          procs 
 us sy id    r     b     w 
  6  4 90    1     0     0
  4  3 93
  4  3 93
  4  3 93
  5  3 92
  5  3 92
  3  3 93
  3  3 94
  5  3 92
  5  3 91
  5  3 91
  5  3 92
  5  5 90
  6  5 89
  8  5 86
  8  5 87

It is interesting to note that "mpsched -s" also shows only 16 processors, however, the IDs shown are all even numbers and correspond to the (I presume) processor IDs shown by sar. Here th "mpsched -s" output:

System Configuration
=====================

Locality Domain Count: 1
Processor Count      : 16

Domain    Processors
------    ----------
   0        0   2   4   6   8  10  12  14  16  18  20  22  24  26  28  30 

Clearly I am missing some key fact about this system. Can someone explain this discrepancy?

Unfortunately glance is not installed on this system.

Robert Urban

[Arnaud Delaloy]

hello,

I has been years since I've worked on PA-RISC  servers , but if I recall correctly the CPU in a RP8420 are PA-8800 and they are dual core ( wikipedia link )

as there can be 4 Cpu per cell , and up to 4 cells in a RP84x0 ; that makes 16 CPUs, but 32 cores.

so iostat reports the cores,  but (iirc) SAR/vmstat only report the CPUS, as the two core in a CPU share the cache and bandwith on the same die..

[Duncan Edmonstone]

It is also a long time for me since looking at this sort of thing on a PA-RISC system, but I thought sar just thought of CPUs as "run queues" and I would have expcted it to see 32 if I'm honest. I do seem to recall if you set things up in an odd way from a partitioning perspective, things could look a bit odd from the OS, but we don't have all the information for that. It would be interesting to see the output of commands to show us the configuration of any nPars, vPars or even processor sets on this system:

parstatus

vparstatus

psrset

outputs would be interesting to see.