1 /* Copyright (c) 2014-2016. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #ifndef SIMGRID_ROUTING_CLUSTER_FAT_TREE_HPP_
7 #define SIMGRID_ROUTING_CLUSTER_FAT_TREE_HPP_
9 #include "src/kernel/routing/ClusterZone.hpp"
15 class XBT_PRIVATE FatTreeLink;
17 /** \brief A node in a fat tree (@ref FatTreeZone).
18 * A FatTreeNode can either be a switch or a processing node. Switches are
19 * identified by a negative ID. This class is closely related to fat
21 class XBT_PRIVATE FatTreeNode {
23 /** Unique ID which identifies every node. */
25 /* Level into the tree, with 0 being the leafs.
28 /* \brief Position into the level, starting from 0.
30 unsigned int position;
31 /** In order to link nodes between them, each one must be assigned a label,
32 * consisting of l integers, l being the levels number of the tree. Each label
33 * is unique in the level, and the way it is generated allows the construction
34 * of a fat tree which fits the desired topology.
36 std::vector<unsigned int> label;
38 /** Links to the lower level, where the position in the vector corresponds to
41 std::vector<FatTreeLink*> children;
42 /** Links to the upper level, where the position in the vector corresponds to
45 std::vector<FatTreeLink*> parents;
47 /** Virtual link standing for the node global capacity.
49 surf::LinkImpl* limiterLink;
50 /** If present, communications from this node to this node will pass through it
51 * instead of passing by an upper level switch.
53 surf::LinkImpl* loopback;
54 FatTreeNode(sg_platf_cluster_cbarg_t cluster, int id, int level, int position);
57 /** \brief Link in a fat tree (@ref FatTreeZone).
59 * Represents a single, duplex link in a fat tree. This is necessary to have a tree.
60 * It is equivalent to a physical link.
64 FatTreeLink(sg_platf_cluster_cbarg_t cluster, FatTreeNode* source, FatTreeNode* destination);
65 /** Link going up in the tree */
66 surf::LinkImpl* upLink;
67 /** Link going down in the tree */
68 surf::LinkImpl* downLink;
69 /** Upper end of the link */
71 /** Lower end of the link */
72 FatTreeNode* downNode;
75 /** @ingroup ROUTING_API
76 * @brief NetZone using a Fat-Tree topology
78 * Generate fat trees according to the topology asked for, according to:
79 * Eitan Zahavi, D-Mod-K Routing Providing Non-Blocking Traffic for Shift
80 * Permutations on Real Life Fat Trees (2010).
82 * RLFT are PGFT with some restrictions to address real world constraints,
83 * which are not currently enforced.
85 * The exact topology is described in the mandatory topo_parameters
86 * field, and follow the "h ; m_h, ..., m_1 ; w_h, ..., w_1 ; p_h, ..., p_1" format.
87 * h stands for the switches levels number, i.e. the fat tree is of height h,
88 * without the processing nodes. m_i stands for the number of lower level nodes
89 * connected to a node in level i. w_i stands for the number of upper levels
90 * nodes connected to a node in level i-1. p_i stands for the number of
91 * parallel links connecting two nodes between level i and i - 1. Level h is
92 * the topmost switch level, level 1 is the lowest switch level, and level 0
93 * represents the processing nodes. The number of provided nodes must be exactly
94 * the number of processing nodes required to fit the topology, which is the
95 * product of the m_i's.
97 * Routing is made using a destination-mod-k scheme.
99 class XBT_PRIVATE FatTreeZone : public ClusterZone {
101 explicit FatTreeZone(NetZone* father, const char* name);
102 ~FatTreeZone() override;
103 void getLocalRoute(NetPoint* src, NetPoint* dst, sg_platf_route_cbarg_t into, double* latency) override;
105 /** \brief Generate the fat tree
107 * Once all processing nodes have been added, this will make sure the fat
108 * tree is generated by calling generateLabels(), generateSwitches() and
109 * then connection all nodes between them, using their label.
111 void seal() override;
112 /** \brief Read the parameters in topo_parameters field.
114 * It will also store the cluster for future use.
116 void parse_specific_arguments(sg_platf_cluster_cbarg_t cluster) override;
117 void addProcessingNode(int id);
118 void generateDotFile(const std::string& filename = "fatTree.dot") const;
121 // description of a PGFT (TODO : better doc)
122 unsigned int levels_ = 0;
123 std::vector<unsigned int> lowerLevelNodesNumber_; // number of children by node
124 std::vector<unsigned int> upperLevelNodesNumber_; // number of parents by node
125 std::vector<unsigned int> lowerLevelPortsNumber_; // ports between each level l and l-1
127 std::map<int, FatTreeNode*> computeNodes_;
128 std::vector<FatTreeNode*> nodes_;
129 std::vector<FatTreeLink*> links_;
130 std::vector<unsigned int> nodesByLevel_;
132 sg_platf_cluster_cbarg_t cluster_ = nullptr;
134 void addLink(FatTreeNode* parent, unsigned int parentPort, FatTreeNode* child, unsigned int childPort);
135 int getLevelPosition(const unsigned int level);
136 void generateLabels();
137 void generateSwitches();
138 int connectNodeToParents(FatTreeNode* node);
139 bool areRelated(FatTreeNode* parent, FatTreeNode* child);
140 bool isInSubTree(FatTreeNode* root, FatTreeNode* node);