About CPU cores numbering an processor affinity

[Dmitry Sivachenko]

Hello!

I am using FreeBSD-9-STABLE on the following hardware:

FreeBSD/SMP: Multiprocessor System Detected: 24 CPUs
FreeBSD/SMP: 2 package(s) x 6 core(s) x 2 SMT threads

So I have 2 physical CPUs with 6 core each.

# cpuset -g
pid -1 mask: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23


So each of 24 cores are numbered 0..23.

1) In what particular order are these cores numbered?  Can I assume that 0..11 correspond to 1st physical CPU and 12..23 to second?  How SMT threads are numbered within each core?

2) This machine has Intel network adapter (em driver).  I want to pin network interrupt thread and proxy software to the same processor so they share at least L2 or L3 cache.  How can I do this?  From the one hand, I see the following processes:

   11 root         -92    -     0K   720K WAIT   19 146:38  0.00% intr{irq260: em1:rx 0}
   11 root         -92    -     0K   720K WAIT   19  15:11  0.00% intr{irq261: em1:tx 0}

From the other hand, the following processes seems to be unrelated to network but they share same PID:
   11 root         -60    -     0K   720K WAIT    1 131:20  0.00% intr{swi4: clock}
   11 root         -88    -     0K   720K WAIT   17  40:03  0.00% intr{irq263: ahci0}
   11 root         -72    -     0K   720K WAIT   22  17:35  0.00% intr{swi1: netisr 0}
   11 root         -88    -     0K   720K WAIT    3   3:08  0.00% intr{irq256: mfi0}

Should I use "-x" option of cpuset for that purpose (to bind irq 260 and 261 in my example)?

Thanks in advance!