1 /*
   2  * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 #include "precompiled.hpp"
  25 #include "gc/z/zCPU.hpp"
  26 #include "logging/log.hpp"
  27 #include "memory/padded.inline.hpp"
  28 #include "runtime/os.hpp"
  29 #include "runtime/thread.inline.hpp"
  30 #include "utilities/debug.hpp"
  31 
  32 #define ZCPU_UNKNOWN_AFFINITY (Thread*)-1;
  33 #define ZCPU_UNKNOWN_SELF     (Thread*)-2;
  34 
  35 PaddedEnd<ZCPU::ZCPUAffinity>* ZCPU::_affinity = NULL;
  36 __thread Thread*  ZCPU::_self                  = ZCPU_UNKNOWN_SELF;
  37 __thread uint32_t ZCPU::_cpu                   = 0;
  38 
  39 void ZCPU::initialize() {
  40   assert(_affinity == NULL, "Already initialized");
  41   const uint32_t ncpus = count();
  42 
  43   _affinity = PaddedArray<ZCPUAffinity, mtGC>::create_unfreeable(ncpus);
  44 
  45   for (uint32_t i = 0; i < ncpus; i++) {
  46     _affinity[i]._thread = ZCPU_UNKNOWN_AFFINITY;
  47   }
  48 
  49   log_info(gc, init)("CPUs: %u total, %u available",
  50                      os::processor_count(),
  51                      os::initial_active_processor_count());
  52 }
  53 
  54 uint32_t ZCPU::count() {
  55   return os::processor_count();
  56 }
  57 
  58 uint32_t ZCPU::id() {
  59   assert(_affinity != NULL, "Not initialized");
  60 
  61   // Fast path
  62   if (_affinity[_cpu]._thread == _self) {
  63     return _cpu;
  64   }
  65 
  66   // Slow path
  67   _self = Thread::current();
  68   _cpu = os::processor_id();
  69 
  70   // Update affinity table
  71   _affinity[_cpu]._thread = _self;
  72 
  73   return _cpu;
  74 }