TORUS-2QOS.CONF(5) OpenIB Management TORUS-2QOS.CONF(5)NAMEtorus-2QoS.conf - Torus-2QoS configuration for OpenSM subnet manager
DESCRIPTION
The file torus-2QoS.conf contains configuration information that is
specific to the OpenSM routing engine torus-2QoS. Blank lines and
lines where the first non-whitespace character is "#" are ignored. A
token is any contiguous group of non-whitespace characters. Any tokens
on a line following the recognized configuration tokens described below
are ignored.
[torus|mesh] x_radix[m|M|t|T] y_radix[m|M|t|T] z_radix[m|M|t|T]
Either torus or mesh must be the first keyword in the configura‐
tion, and sets the topology that torus-2QoS will try to con‐
struct. A 2D topology can be configured by specifying one of
x_radix, y_radix, or z_radix as 1. An individual dimension can
be configured as mesh (open) or torus (looped) by suffixing its
radix specification with one of m, M, t, or T. Thus, "mesh 3T 4
5" and "torus 3 4M 5M" both specify the same topology.
Note that although torus-2QoS can route mesh fabrics, its abil‐
ity to route around failed components is severely compromised on
such fabrics. A failed fabric component is very likely to cause
a disjoint ring; see UNICAST ROUTING in torus-2QoS(8).
xp_link sw0_GUID sw1_GUID
yp_link sw0_GUID sw1_GUID
zp_link sw0_GUID sw1_GUID
xm_link sw0_GUID sw1_GUID
ym_link sw0_GUID sw1_GUID
zm_link sw0_GUID sw1_GUID
These keywords are used to seed the torus/mesh topology. For
example, "xp_link 0x2000 0x2001" specifies that a link from the
switch with node GUID 0x2000 to the switch with node GUID 0x2001
would point in the positive x direction, while "xm_link 0x2000
0x2001" specifies that a link from the switch with node GUID
0x2000 to the switch with node GUID 0x2001 would point in the
negative x direction. All the link keywords for a given seed
must specify the same "from" switch.
In general, it is not necessary to configure both the positive
and negative directions for a given coordinate; either is suffi‐
cient. However, the algorithm used for topology discovery needs
extra information for torus dimensions of radix four (see TOPOL‐
OGY DISCOVERY in torus-2QoS(8)). For such cases both the posi‐
tive and negative coordinate directions must be specified.
Based on the topology specified via the torus/mesh keyword,
torus-2QoS will detect and log when it has insufficient seed
configuration.
x_dateline position
y_dateline position
z_dateline position
In order for torus-2QoS to provide the guarantee that path SL
values do not change under any conditions for which it can still
route the fabric, its idea of dateline position must not change
relative to physical switch locations. The dateline keywords
provide the means to configure such behavior.
The dateline for a torus dimension is always between the switch
with coordinate 0 and the switch with coordinate radix-1 for
that dimension. By default, the common switch in a torus seed
is taken as the origin of the coordinate system used to describe
switch location. The position parameter for a dateline keyword
moves the origin (and hence the dateline) the specified amount
relative to the common switch in a torus seed.
next_seed
If any of the switches used to specify a seed were to fail
torus-2QoS would be unable to complete topology discovery suc‐
cessfully. The next_seed keyword specifies that the following
link and dateline keywords apply to a new seed specification.
For maximum resiliency, no seed specification should share a
switch with any other seed specification. Multiple seed speci‐
fications should use dateline configuration to ensure that
torus-2QoS can grant path SL values that are constant, regard‐
less of which seed was used to initiate topology discovery.
portgroup_max_ports max_ports
This keyword specifies the maximum number of parallel inter-
switch links, and also the maximum number of host ports per
switch, that torus-2QoS can accommodate. The default value is
16. Torus-2QoS will log an error message during topology dis‐
covery if this parameter needs to be increased. If this keyword
appears multiple times, the last instance prevails.
Note that the switch management port (switch port 0) gets put
into the same port group with the host ports, so if you have 16
host ports per switch, portgroup_max_ports would need to be at
least 17.
port_order p1 p2 p3 ...
This keyword specifies the order in which CA ports on a destina‐
tion switch are visited when computing routes. When the fabric
contains switches connected with multiple parallel links, routes
are distributed in a round-robin fashion across such links, and
so changing the order that CA ports are visited changes the dis‐
tribution of routes across such links. This may be advantageous
for some specific traffic patterns.
The default is to visit CA ports in increasing port order on
destination switches.
Duplicate values in the list will be ignored.
EXAMPLE
# Look for a 2D (since x radix is one) 4x5 torus.
torus 1 4 5
# y is radix-4 torus dimension, need both
# ym_link and yp_link configuration.
yp_link 0x200000 0x200005 # sw @ y=0,z=0 -> sw @ y=1,z=0
ym_link 0x200000 0x20000f # sw @ y=0,z=0 -> sw @ y=3,z=0
# z is not radix-4 torus dimension, only need one of
# zm_link or zp_link configuration.
zp_link 0x200000 0x200001 # sw @ y=0,z=0 -> sw @ y=0,z=1
next_seed
yp_link 0x20000b 0x200010 # sw @ y=2,z=1 -> sw @ y=3,z=1
ym_link 0x20000b 0x200006 # sw @ y=2,z=1 -> sw @ y=1,z=1
zp_link 0x20000b 0x20000c # sw @ y=2,z=1 -> sw @ y=2,z=2
y_dateline -2 # Move the dateline for this seed
z_dateline -1 # back to its original position.
# If OpenSM failover is configured, for maximum resiliency
# one instance should run on a host attached to a switch
# from the first seed, and another instance should run
# on a host attached to a switch from the second seed.
# Both instances should use this torus-2QoS.conf to ensure
# path SL values do not change in the event of SM failover.
# port_order defines the order on which the ports would be
# chosen for routing.
port_order 7 10 8 11 9 12 25 28 26 29 27 30
FILES
/etc/rdma/torus-2QoS.conf
Default torus-2QoS config file.
SEE ALSOopensm(8), torus-2QoS(8).
OpenIB November 7, 2011 TORUS-2QOS.CONF(5)
