1. A method for tracing a program executed on a system having a plurality of nodes, which are interconnected by a bus and each of which is configured by one or more processing unit(s) and a primary storage area, to which each of the one or more processing unit(s) makes an access when executing a trace process, wherein: a predetermined processing unit among the plurality of processing units, secures a tracer storage destination/trace information output destination storage area, which makes a correspondence between a storage destination of a tracer and an output destination of trace information in a primary storage area for each processing unit, in a primary storage area of a node of the predetermined processing unit itself; each processing unit secures an area, to which the trace information is output, in the primary storage area of the node of the processing unit itself; processing unit(s) other than processing unit(s) of the node where a storage source area of the tracer that executes a trace exists among the plurality of processing units, secure(s) the area for storing the tracer in the primary storage area of the node of the processing unit itself, and copies (copy) the tracer from the storage source area of the tracer, to the secured area; each processing unit writes information about the output destination area of the trace information and about the storage destination area of the tracer of the processing unit itself to the tracer storage destination/trace information output destination storage area; a processing unit that is responsible for a task writes information for identifying the responsible processing unit itself, and the storage destination of the tracer and the output destination of the trace information, which correspond to the responsible processing unit itself, to a task control block based on the tracer storage destination/trace information output destination storage area when the task control block of the program to be traced is generated; the responsible processing unit obtains the storage destination of the tracer and the output destination of the trace information from the task control block of the program when the program to be traced is executed; and the responsible processing unit executes the tracer stored at the obtained storage destination of the tracer, and outputs the trace information to the obtained output destination.