code_changes.md

The major changes made to the SLURM source code are present in the following files:

src/common

• node_conf.h - Add the field leaf_switch to struct node_record. This field maintains the leaf switch to which the node is connected.
• slurm_topology.h - Add the following fields to struct switch_record: comm_jobs (no of communication-intensive jobs on the switch) and num_nodes (no of direct descendant nodes).

src/slurmctld:

• job_scheduler.c - The function _schedule() calls the hop function to record the cost of communication for jobs when they start.
• calc_hops.c - The file contains most of the additional code. It includes functions to calculate cost of communication for different patterns and functions to determine node allocation under balanced allocation and adaptive allocation.
• read_config.c, node_mgr.c, job_mgr.c - The field comm_jobs for each switch is updated in these files when a job starts or finishes. The changes can be located using the environment variable JOBAWARE.

src/plugins:

• sched/backfill/backfill.c - The function _start_job() calls the hop function to record the cost of communication for backfilled jobs when they start.
• topology/tree/topology_tree.c - Changes are made to the validate_switches() function to initialize the fields leaf_switch, comm_jobs and num_nodes added above.
• select/linear/select_linear.c - Changes are made to the _job_test_topo() function to implement the proposed algorithms.