silo/core.cc

   1 #include <unistd.h>
   2
   3 #include "amd64.h"
   4 #include "core.h"
   5 #include "util.h"
   6
   7 using namespace std;
   8 using namespace util;
   9
  10 int
  11 coreid::allocate_contiguous_aligned_block(unsigned n, unsigned alignment)
  12 {
  13 retry:
  14   unsigned current = g_core_count.load(memory_order_acquire);
  15   const unsigned rounded = slow_round_up(current, alignment);
  16   const unsigned replace = rounded + n;
  17   if (unlikely(replace > NMaxCores))
  18     return -1;
  19   if (!g_core_count.compare_exchange_strong(current, replace, memory_order_acq_rel)) {
  20     nop_pause();
  21     goto retry;
  22   }
  23   return rounded;
  24 }
  25
  26 unsigned
  27 coreid::num_cpus_online()
  28 {
  29   const long nprocs = sysconf(_SC_NPROCESSORS_ONLN);
  30   ALWAYS_ASSERT(nprocs >= 1);
  31   return nprocs;
  32 }
  33
  34 __thread int coreid::tl_core_id = -1;
  35 atomic<unsigned> coreid::g_core_count(0);