1GETNTYPE(2) LAM NETWORK LIBRARY GETNTYPE(2)
2
6 getnodeid, getnodetype, getorigin, getncomp, getnotb, getnall, getntype
7 - Get information on LAM nodes.
8
10 #include <net.h>
11 int getnodeid ();
13 int getnodetype ();
14 int getorigin ();
15 int getnall ();
17 int getncomp ();
18 int getnjones ();
19 int getnotb ();
20 int getntype (int nodetype, int typemask);
21
23 integer function IGNDID ()
24 integer function IGNDTP ()
25 integer function IGORGN ()
26 integer function IGNALL ()
28 integer function IGNCMP ()
29 integer function IGNJON ()
30 integer function IGNOTB ()
31 integer function IGNTP (nodetype, typemask)
32 integer nodetype, typemask
34
36 These functions return node information obtained from the local route
37 daemon, a modular component of the LAM daemon, regarding the currently
38 running LAM network. A node is defined by its identifier, an arbitrary
39 32 bit value, and its type, a combination of flags describing the capa‐
40 bilities of the node. These flags (see CONSTANTS(5) and/or <net.h>)
41 are:
42 NT_ITB node running LAM natively
44 NT_CAST node multicast, a group of nodes
46 NT_WASTE node not part of main computing group
48 NT_DISK node has a disk
50 NT_TUBE node has a video display unit
52 NT_JONES node is a neighbour of the local node
54 NT_BOOT node is booted by the local node
56 getnodeid() returns the local node identifier. getnodetype() returns
58 the local node type. getorigin() returns the origin node identifier,
59 from which LAM was booted.
60 getncomp() returns the number of nodes marked for the "main" computa‐
62 tion. A typical application will use most (maybe all) of the nodes in
63 a parallel machine to compute portions of decomposed data. Programmers
64 frequently need to know the number of these "compute" nodes. Other
65 nodes may be present in the multicomputer to handle peripherals or se‐
66 quential portions of an application.
67 getnotb() returns the total number of OTB nodes. getnall() returns the
69 total number of nodes in the system. getnjones() returns the caller's
70 number of neighbour (directly connected) nodes.
71 getntype() is a general function that is used to determine the number
73 of nodes whose node types have certain bits set to certain values.
74 This is a flexible tool which allows the user to obtain very specific
75 information about the capabilities of nodes in the system.
76 Type Inquiries
78 You may need more detailed information on the number and types of nodes
79 in the system than provided by the convenience functions. You may, for
80 example, want to know the number of computing nodes with attached video
81 displays. The getntype() function is used for this purpose.
82 Node types are interpreted as bit fields, and each node type has a dif‐
84 ferent bit set. A bitmask having all bits set, NT_ALL, is also avail‐
85 able. Note that NT_ALL does not include NT_JONES nor NT_BOOT since
86 these node characteristics are not inherent to the nodes, but depend on
87 the node from which the query is made. The node types are thus:
88 Nodetype Value Bitmask
90 NT_ITB 1 ...00000001
92 NT_CAST 2 ...00000010
93 NT_WASTE 4 ...00000100
94 NT_DISK 8 ...00001000
95 NT_TUBE 16 ...00010000
96 NT_ALL 31 ...00011111
97 NT_JONES 32 ...00100000
98 NT_BOOT 64 ...01000000
99 The typemask argument to getntype() is used to specify which bits are
101 of interest. These are set to 1, all others are set to 0. The node‐
102 type argument is used to specify what values these bits should take.
103 getntype() then compares the relevant bits (as specified by typemask)
104 in the node type of each node in the system, to see if they have the
105 appropriate value (as specified by nodetype).
106 To learn the number of nodes that have video capabilities, the bits of
108 interest are NT_WASTE and NT_TUBE, thus typemask is 20. NT_WASTE must
109 be 0 and NT_TUBE must be 1, which combined gives nodetype as 16. The
110 complete call to getntype() is:
111 nnodes = getntype(NT_TUBE, NT_TUBE | NT_WASTE);
113 To learn the number of compute nodes that have an attached video dis‐
115 play, but no other capabilities, all bits must be considered and all
116 bits except NT_TUBE must be clear (0). The complete function call is:
117 nnodes = getntype(NT_TUBE, NT_ALL);
119
121 getnodeid() and getorigin() both return node identifiers. NOTNODEID
122 (defined in <net.h>) is returned if an error occurred. Likewise, getn‐
123 odetype() returns a valid node type or NOTNODETYPE in the case of er‐
124 ror. The return values upon successful completion for the remaining
125 functions are described above; they return -1 if an error occurs. In
126 all cases of error, the global error variable errno is set to indicate
127 the error.
128
130 IGNDID() and IGORGN() both return node identifiers. NOTNODEID (see
131 CONSTANTS(5)) is returned if an error occurred. Likewise, IGNDTP() re‐
132 turns a valid node type or NOTNODETYPE in the case of error. The re‐
133 turn values upon successful completion for the remaining functions are
134 described above; they return -1 if an error occurs.
135
137 getroute(2), CONSTANTS(5)
138LAM 7.1.2 March, 2006 GETNTYPE(2)