1 /*
   2  * Copyright (c) 1998, 2010, 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
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  23  */
  24 
  25 #ifndef OS_CPU_SOLARIS_SPARC_VM_THREADLS_SOLARIS_SPARC_HPP
  26 #define OS_CPU_SOLARIS_SPARC_VM_THREADLS_SOLARIS_SPARC_HPP
  27 
  28 public:
  29   // Java Thread  - force inlining
  30   static inline Thread* thread() ;
  31 
  32 private:
  33   static Thread* _get_thread_cache[];  // index by [(raw_id>>9)^(raw_id>>20) % _pd_cache_size]
  34   static Thread* get_thread_via_cache_slowly(uintptr_t raw_id, int index);
  35 
  36   NOT_PRODUCT(static int _tcacheHit;)
  37   NOT_PRODUCT(static int _tcacheMiss;)
  38 
  39 public:

  40 
  41   // Print cache hit/miss statistics
  42   static void print_statistics() PRODUCT_RETURN;
  43 
  44   enum Constants {
  45     _pd_cache_size         =  256*2  // projected typical # of threads * 2
  46   };
  47 
  48   static void set_thread_in_slot (Thread *) ;
  49 
  50   static uintptr_t pd_raw_thread_id() {
  51     return _raw_thread_id();
  52   }
  53 
  54   static int pd_cache_index(uintptr_t raw_id) {
  55     // Hash function: From email from Dave:
  56     // The hash function deserves an explanation.  %g7 points to libthread's
  57     // "thread" structure.  On T1 the thread structure is allocated on the
  58     // user's stack (yes, really!) so the ">>20" handles T1 where the JVM's
  59     // stack size is usually >= 1Mb.  The ">>9" is for T2 where Roger allocates
  60     // globs of thread blocks contiguously.  The "9" has to do with the
  61     // expected size of the T2 thread structure.  If these constants are wrong
  62     // the worst thing that'll happen is that the hit rate for heavily threaded
  63     // apps won't be as good as it could be.  If you want to burn another
  64     // shift+xor you could mix together _all of the %g7 bits to form the hash,
  65     // but I think that's excessive.  Making the change above changed the
  66     // T$ miss rate on SpecJBB (on a 16X system) from about 3% to imperceptible.
  67     uintptr_t ix = (int) (((raw_id >> 9) ^ (raw_id >> 20)) % _pd_cache_size);
  68     return ix;
  69   }
  70 
  71 #endif // OS_CPU_SOLARIS_SPARC_VM_THREADLS_SOLARIS_SPARC_HPP
--- EOF ---