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Date:      Mon, 26 Aug 2013 17:33:26 +0400
From:      Dmitry Sivachenko <trtrmitya@gmail.com>
To:        freebsd-threads@freebsd.org
Subject:   About CPU cores numbering an processor affinity
Message-ID:  <970B3263-4689-4F8A-B012-DA88A1266F45@gmail.com>
References:  <1D21F5BC-63CD-4B33-9286-6687E62FDB15@gmail.com>

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Nobody answered on -hackers, I try to ask there.

Begin forwarded message:

> From: Dmitry Sivachenko <trtrmitya@gmail.com>
> Subject: About CPU cores numbering an processor affinity
> Date: 23 =D0=B0=D0=B2=D0=B3=D1=83=D1=81=D1=82=D0=B0 2013 =D0=B3., =
17:23:51 GMT+04:00
> To: hackers@freebsd.org
>=20
> Hello!
>=20
> I am using FreeBSD-9-STABLE on the following hardware:
>=20
> FreeBSD/SMP: Multiprocessor System Detected: 24 CPUs
> FreeBSD/SMP: 2 package(s) x 6 core(s) x 2 SMT threads
>=20
> So I have 2 physical CPUs with 6 core each.
>=20
> # 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
>=20
>=20
> So each of 24 cores are numbered 0..23.
>=20
> 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?
>=20
> 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?  =46rom the one =
hand, I see the following processes:
>=20
>   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}
>=20
> =46rom 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}
>=20
> Should I use "-x" option of cpuset for that purpose (to bind irq 260 =
and 261 in my example)?
>=20
> Thanks in advance!
>=20




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