issue #76: added cds::atomicity::cache_friendly_item_counter to avoid false sharing

[libcds.git] / cds / intrusive / details / michael_set_base.h

diff --git a/cds/intrusive/details/michael_set_base.h b/cds/intrusive/details/michael_set_base.h
index bc8490e709d7a1033b637cfde868dd2efa6dfb9b..8e63cf3849b49d5f38382cb7badd601b047d734c 100644 (file)
--- a/cds/intrusive/details/michael_set_base.h
+++ b/cds/intrusive/details/michael_set_base.h
@@ -1,11 +1,11 @@
 /*
     This file is a part of libcds - Concurrent Data Structures library
 
-    (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
+    (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
 
     Source code repo: http://github.com/khizmax/libcds/
     Download: http://sourceforge.net/projects/libcds/files/
-    
+
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions are met:
 
@@ -58,9 +58,10 @@ namespace cds { namespace intrusive {
             /**
                 The item counting is an important part of \p MichaelHashSet algorithm:
                 the \p empty() member function depends on correct item counting.
-                Therefore, \p atomicity::empty_item_counter is not allowed as a type of the option.
+                You may use \p atomicity::empty_item_counter if don't need \p empty() and \p size()
+                member functions.
 
-                Default is \p atomicity::item_counter.
+                Default is \p atomicity::item_counter; to avoid false sharing you may use \p atomicity::cache_friendly_item_counter
             */
             typedef cds::atomicity::item_counter item_counter;
 
@@ -134,11 +135,11 @@ namespace cds { namespace intrusive {
                 void next()
                 {
                     if ( m_pCurBucket < m_pEndBucket ) {
-                        if ( ++m_itList != m_pCurBucket->end() )
+                        if ( ++m_itList != m_pCurBucket->end())
                             return;
                         while ( ++m_pCurBucket < m_pEndBucket ) {
                             m_itList = m_pCurBucket->begin();
-                            if ( m_itList != m_pCurBucket->end() )
+                            if ( m_itList != m_pCurBucket->end())
                                 return;
                         }
                     }
@@ -162,7 +163,7 @@ namespace cds { namespace intrusive {
                     , m_itList( it )
                     , m_pEndBucket( pLast )
                 {
-                    if ( it == pFirst->end() )
+                    if ( it == pFirst->end())
                         next();
                 }
 
@@ -204,6 +205,11 @@ namespace cds { namespace intrusive {
                     return m_pCurBucket != m_pEndBucket ? m_pCurBucket : nullptr;
                 }
 
+                list_iterator const& underlying_iterator() const
+                {
+                    return m_itList;
+                }
+
                 template <bool C>
                 bool operator ==(iterator<bucket_type, C> const& i) const
                 {
@@ -214,7 +220,6 @@ namespace cds { namespace intrusive {
                 {
                     return !( *this == i );
                 }
-
             };
         }
         //@endcond