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added latch-free erasure

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This commit is contained in:
joaquintides
2023-12-05 12:20:40 +01:00
parent 86856f7e6b
commit 0f2a2a0b0f
2 changed files with 34 additions and 1 deletions
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31
include/boost/unordered/detail/foa/concurrent_table.hpp
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@ -799,6 +799,34 @@ public:
return erase_if(x,[](const value_type&){return true;});
}
#if defined(BOOST_UNORDERED_LATCH_FREE)
template<typename Key,typename F>
BOOST_FORCEINLINE auto erase_if(const Key& x,F&& f)->typename std::enable_if<
!is_execution_policy<Key>::value,std::size_t>::type
{
auto lck=shared_access();
auto hash=this->hash_for(x);
std::size_t res=0;
unprotected_internal_visit(
group_shared{},x,this->position_for(hash),hash,
[&,this](group_type* pg,unsigned int n,element_type* p)
{
auto expected=group_type::reduced_hash(hash);
if(reinterpret_cast<std::atomic<unsigned char>*>(pg)[n].
compare_exchange_strong(expected,1)){
if(f(cast_for(group_shared{},type_policy::value_from(*p)))){
wait_for_epochs();
super::erase(pg,n,p);
res=1;
}
else{
pg->set(n,expected);
}
}
});
return res;
}
#else
template<typename Key,typename F>
BOOST_FORCEINLINE auto erase_if(const Key& x,F&& f)->typename std::enable_if<
!is_execution_policy<Key>::value,std::size_t>::type
@ -817,6 +845,7 @@ public:
});
return res;
}
#endif
template<typename F>
std::size_t erase_if(F&& f)
@ -1825,7 +1854,7 @@ private:
void wait_for_epochs()
{
for(std::size_t i=0;i<epochs.size();++i){
while(epochs[i].load(std::memory_order_acquire)){}
while(epochs[i].load(std::memory_order_acquire)>1){}
}
}
#endif

4
include/boost/unordered/detail/foa/core.hpp
View File

@ -382,11 +382,13 @@ private:
return (int)word[narrow_cast<unsigned char>(hash)];
}
public:
inline static unsigned char reduced_hash(std::size_t hash)
{
return narrow_cast<unsigned char>(match_word(hash));
}
private:
inline slot_type& at(std::size_t pos)
{
return m[pos];
@ -532,6 +534,7 @@ private:
#endif
}
public:
inline static unsigned char reduced_hash(std::size_t hash)
{
static constexpr unsigned char table[]={
@ -556,6 +559,7 @@ private:
return table[(unsigned char)hash];
}
private:
/* Copied from
* https://github.com/simd-everywhere/simde/blob/master/simde/x86/
* sse2.h#L3763