jdk8-mips64-public/hotspot: src/os_cpu/solaris_sparc/vm/threadLS_solaris

6822204: volatile fences should prefer lock:addl to actual mfence instructions
Reviewed-by: kvn, phh

     1 /*

     2  * Copyright 1998-2005 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    25 public:

    26   // Java Thread  - force inlining

    27   static inline Thread* thread() ;

    29 private:

    30   static Thread* _get_thread_cache[];  // index by [(raw_id>>9)^(raw_id>>20) % _pd_cache_size]

    31   static Thread* get_thread_via_cache_slowly(uintptr_t raw_id, int index);

    33   NOT_PRODUCT(static int _tcacheHit;)

    34   NOT_PRODUCT(static int _tcacheMiss;)

    36 public:

    38   // Print cache hit/miss statistics

    39   static void print_statistics() PRODUCT_RETURN;

    41   enum Constants {

    42     _pd_cache_size         =  256*2  // projected typical # of threads * 2

    43   };

    45   static void set_thread_in_slot (Thread *) ;

    47   static uintptr_t pd_raw_thread_id() {

    48     return _raw_thread_id();

    49   }

    51   static int pd_cache_index(uintptr_t raw_id) {

    52     // Hash function: From email from Dave:

    53     // The hash function deserves an explanation.  %g7 points to libthread's

    54     // "thread" structure.  On T1 the thread structure is allocated on the

    55     // user's stack (yes, really!) so the ">>20" handles T1 where the JVM's

    56     // stack size is usually >= 1Mb.  The ">>9" is for T2 where Roger allocates

    57     // globs of thread blocks contiguously.  The "9" has to do with the

    58     // expected size of the T2 thread structure.  If these constants are wrong

    59     // the worst thing that'll happen is that the hit rate for heavily threaded

    60     // apps won't be as good as it could be.  If you want to burn another

    61     // shift+xor you could mix together _all of the %g7 bits to form the hash,

    62     // but I think that's excessive.  Making the change above changed the

    63     // T$ miss rate on SpecJBB (on a 16X system) from about 3% to imperceptible.

    64     uintptr_t ix = (int) (((raw_id >> 9) ^ (raw_id >> 20)) % _pd_cache_size);

    65     return ix;

    66   }

src/os_cpu/solaris_sparc/vm/threadLS_solaris_sparc.hpp@d0994e5bebce