void initCapabilities()

in rts/Capability.c [334:400]

• 49 lines of code
• 9 McCabe index (conditional complexity)

void initCapabilities (void)
{
    uint32_t i;

    /* Declare a couple capability sets representing the process and
       clock domain. Each capability will get added to these capsets. */
    traceCapsetCreate(CAPSET_OSPROCESS_DEFAULT, CapsetTypeOsProcess);
    traceCapsetCreate(CAPSET_CLOCKDOMAIN_DEFAULT, CapsetTypeClockdomain);

    // Initialise NUMA
    if (!RtsFlags.GcFlags.numa) {
        n_numa_nodes = 1;
        for (i = 0; i < MAX_NUMA_NODES; i++) {
            numa_map[i] = 0;
        }
    } else {
        uint32_t nNodes = osNumaNodes();
        if (nNodes > MAX_NUMA_NODES) {
            barf("Too many NUMA nodes (max %d)", MAX_NUMA_NODES);
        }
        StgWord mask = RtsFlags.GcFlags.numaMask & osNumaMask();
        uint32_t logical = 0, physical = 0;
        for (; physical < MAX_NUMA_NODES; physical++) {
            if (mask & 1) {
                numa_map[logical++] = physical;
            }
            mask = mask >> 1;
        }
        n_numa_nodes = logical;
        if (logical == 0) {
            barf("available NUMA node set is empty");
        }
    }

#if defined(THREADED_RTS)

#if !defined(REG_Base)
    // We can't support multiple CPUs if BaseReg is not a register
    if (RtsFlags.ParFlags.nCapabilities > 1) {
        errorBelch("warning: multiple CPUs not supported in this build, reverting to 1");
        RtsFlags.ParFlags.nCapabilities = 1;
    }
#endif

    n_capabilities = 0;
    moreCapabilities(0, RtsFlags.ParFlags.nCapabilities);
    n_capabilities = RtsFlags.ParFlags.nCapabilities;

#else /* !THREADED_RTS */

    n_capabilities = 1;
    capabilities = stgMallocBytes(sizeof(Capability*), "initCapabilities");
    capabilities[0] = &MainCapability;

    initCapability(&MainCapability, 0);

#endif

    enabled_capabilities = n_capabilities;

    // There are no free capabilities to begin with.  We will start
    // a worker Task to each Capability, which will quickly put the
    // Capability on the free list when it finds nothing to do.
    for (i = 0; i < n_numa_nodes; i++) {
        last_free_capability[i] = capabilities[0];
    }
}