5.4 CCS: system handlers

The CCS runtime system provides several built-in CCS handlers, which are available in any CONVERSE job:

ccs_getinfo Takes an empty message, responds with information about the parallel job. The response is in the form of network byte order (big-endian) 4-byte integers: first the number of parallel nodes, then the number of processors on each node. This handler is invoked by the client routine CcsConnect.

ccs_killport Allows a client to be notified when a parallel run exits (for any reason). Takes one network byte order (big-endian) 4-byte integer: a TCP port number. The runtime writes ``die
n'' to this port before exiting. There is no response data.

perf_monitor Takes an empty message, responds (after a delay) with performance data. When CMK_WEB_MODE is enabled in conv-mach.h, the runtime system collects performance data. Every 2 seconds, this data is collected on processor 0 and sent to any clients that have invoked perf_monitor on processor 0. The data is returned in ASCII format with the leading string "perf", and for each processor the current load (in percent) and scheduler message queue length (in messages). Thus a heavily loaded, two-processor system might reply with the string ``perf 98 148230 100 385401''.