Passing objects atomically across threads without locks or data races for audio synchronizationTwo threads...
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Passing objects atomically across threads without locks or data races for audio synchronization
Two threads working on shared dataPolymorphic STL foreach without passing the container typePass pointer data across multiple functionsPassing objects to functions safely and efficientlyQueue implementation without using built-in data structuresShare data and mutexes across threadsPassing C++ objects by reference for participants in a simulated battleSharing data between two threads C++Passing Objects of Classes to other ClassCRC without knowing the data type or size
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I am learning about one of the hardest parts of Audio development: the synchronization between the audio thread and the GUI thread. Per the discussion here https://forum.juce.com/t/timur-doumler-talks-on-c-audio-sharing-data-across-threads/26311 and here: https://stackoverflow.com/questions/15460829/lock-free-swap-of-two-unique-ptrt
I'm wondering if the following class solves the problem or comes close to solving it.
template<typename T>
struct SmartAtomicPtr
{
SmartAtomicPtr( T* newT )
{
update( newT );
}
~SmartAtomicPtr()
{
update(nullptr);
}
void update( T* newT, std::memory_order ord = memory_order_seq_cst )
{
keepAlive.reset( atomicTptr.exchange( newT, ord ) );
}
std::shared_ptr<T> getShared(std::memory_order ord = memory_order_seq_cst)
{
return std::make_shared<T>( atomicTptr.load(ord) );
}
T* getRaw(std::memory_order ord = memory_order_seq_cst)
{
return atomicTptr.load(ord);
}
private:
std::atomic<T*> atomicTptr{nullptr};
std::shared_ptr<T> keepAlive;
};
I know that whatever value ends up in the shared_ptr won't be deleted until the SmartAtomicPtr goes out of scope, which is fine.
the ultimate goal would be a lock-free, wait-free solution.
an example of where this might get used is the following interleaving of the audio and message thread. The goal is to keep the returned object from dangling
/*
AudioProcessor owns a SmartAtomicPtr<T> ptr that the message
thread has public access to.
*/
/* audio thread */ auto* t = ptr.getRaw();
/* message thread */ processor.ptr.update( new T() );
/* audio thread */ t->doSomething(); //t is a dangling pointer now
with getShared(), I believe that t no longer dangles:
/* audio thread */ auto t = ptr.getShared();
/* message thread */ processor.ptr.update( new T() );
/* audio thread */ t->doSomething(); //t is one of 2 shared_ptrs
//holding the previous atomic value of ptr
I ran into some double-deletes, but I believe I have solved them, and also prevented the shared_ptr member from being stomped on in the event you call getShared() and update() at the same time, and also kept it leak-free.
any thoughts?
c++ pointers audio lock-free atomic
edited 8 mins ago
200_success
130k16153417
asked 13 hours ago
MatkatMusicMatkatMusic
82
New contributor
MatkatMusic is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I am learning about one of the hardest parts of Audio development: the synchronization between the audio thread and the GUI thread. Per the discussion here https://forum.juce.com/t/timur-doumler-talks-on-c-audio-sharing-data-across-threads/26311 and here: https://stackoverflow.com/questions/15460829/lock-free-swap-of-two-unique-ptrt
I'm wondering if the following class solves the problem or comes close to solving it.
template<typename T>
struct SmartAtomicPtr
{
SmartAtomicPtr( T* newT )
{
update( newT );
}
~SmartAtomicPtr()
{
update(nullptr);
}
void update( T* newT, std::memory_order ord = memory_order_seq_cst )
{
keepAlive.reset( atomicTptr.exchange( newT, ord ) );
}
std::shared_ptr<T> getShared(std::memory_order ord = memory_order_seq_cst)
{
return std::make_shared<T>( atomicTptr.load(ord) );
}
T* getRaw(std::memory_order ord = memory_order_seq_cst)
{
return atomicTptr.load(ord);
}
private:
std::atomic<T*> atomicTptr{nullptr};
std::shared_ptr<T> keepAlive;
};
I know that whatever value ends up in the shared_ptr won't be deleted until the SmartAtomicPtr goes out of scope, which is fine.
the ultimate goal would be a lock-free, wait-free solution.
an example of where this might get used is the following interleaving of the audio and message thread. The goal is to keep the returned object from dangling
/*
AudioProcessor owns a SmartAtomicPtr<T> ptr that the message
thread has public access to.
*/
/* audio thread */ auto* t = ptr.getRaw();
/* message thread */ processor.ptr.update( new T() );
/* audio thread */ t->doSomething(); //t is a dangling pointer now
with getShared(), I believe that t no longer dangles:
/* audio thread */ auto t = ptr.getShared();
/* message thread */ processor.ptr.update( new T() );
/* audio thread */ t->doSomething(); //t is one of 2 shared_ptrs
//holding the previous atomic value of ptr
I ran into some double-deletes, but I believe I have solved them, and also prevented the shared_ptr member from being stomped on in the event you call getShared() and update() at the same time, and also kept it leak-free.
any thoughts?
c++ pointers audio lock-free atomic
edited 8 mins ago
200_success
130k16153417
asked 13 hours ago
MatkatMusicMatkatMusic
82
New contributor
MatkatMusic is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
From C++20, there'sstd::atomic<shared_ptr<T>>partial specialization. You'll want to understand how it works if you're implementing your own.
$endgroup$
– Toby Speight
9 hours ago
add a comment |
$begingroup$
I am learning about one of the hardest parts of Audio development: the synchronization between the audio thread and the GUI thread. Per the discussion here https://forum.juce.com/t/timur-doumler-talks-on-c-audio-sharing-data-across-threads/26311 and here: https://stackoverflow.com/questions/15460829/lock-free-swap-of-two-unique-ptrt
I'm wondering if the following class solves the problem or comes close to solving it.
template<typename T>
struct SmartAtomicPtr
{
SmartAtomicPtr( T* newT )
{
update( newT );
}
~SmartAtomicPtr()
{
update(nullptr);
}
void update( T* newT, std::memory_order ord = memory_order_seq_cst )
{
keepAlive.reset( atomicTptr.exchange( newT, ord ) );
}
std::shared_ptr<T> getShared(std::memory_order ord = memory_order_seq_cst)
{
return std::make_shared<T>( atomicTptr.load(ord) );
}
T* getRaw(std::memory_order ord = memory_order_seq_cst)
{
return atomicTptr.load(ord);
}
private:
std::atomic<T*> atomicTptr{nullptr};
std::shared_ptr<T> keepAlive;
};
I know that whatever value ends up in the shared_ptr won't be deleted until the SmartAtomicPtr goes out of scope, which is fine.
the ultimate goal would be a lock-free, wait-free solution.
an example of where this might get used is the following interleaving of the audio and message thread. The goal is to keep the returned object from dangling
/*
AudioProcessor owns a SmartAtomicPtr<T> ptr that the message
thread has public access to.
*/
/* audio thread */ auto* t = ptr.getRaw();
/* message thread */ processor.ptr.update( new T() );
/* audio thread */ t->doSomething(); //t is a dangling pointer now
with getShared(), I believe that t no longer dangles:
/* audio thread */ auto t = ptr.getShared();
/* message thread */ processor.ptr.update( new T() );
/* audio thread */ t->doSomething(); //t is one of 2 shared_ptrs
//holding the previous atomic value of ptr
I ran into some double-deletes, but I believe I have solved them, and also prevented the shared_ptr member from being stomped on in the event you call getShared() and update() at the same time, and also kept it leak-free.
any thoughts?
c++ pointers audio lock-free atomic
edited 8 mins ago
200_success
130k16153417
asked 13 hours ago
MatkatMusicMatkatMusic
82
New contributor
MatkatMusic is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I am learning about one of the hardest parts of Audio development: the synchronization between the audio thread and the GUI thread. Per the discussion here https://forum.juce.com/t/timur-doumler-talks-on-c-audio-sharing-data-across-threads/26311 and here: https://stackoverflow.com/questions/15460829/lock-free-swap-of-two-unique-ptrt
I'm wondering if the following class solves the problem or comes close to solving it.
template<typename T>
struct SmartAtomicPtr
{
SmartAtomicPtr( T* newT )
{
update( newT );
}
~SmartAtomicPtr()
{
update(nullptr);
}
void update( T* newT, std::memory_order ord = memory_order_seq_cst )
{
keepAlive.reset( atomicTptr.exchange( newT, ord ) );
}
std::shared_ptr<T> getShared(std::memory_order ord = memory_order_seq_cst)
{
return std::make_shared<T>( atomicTptr.load(ord) );
}
T* getRaw(std::memory_order ord = memory_order_seq_cst)
{
return atomicTptr.load(ord);
}
private:
std::atomic<T*> atomicTptr{nullptr};
std::shared_ptr<T> keepAlive;
};
I know that whatever value ends up in the shared_ptr won't be deleted until the SmartAtomicPtr goes out of scope, which is fine.
the ultimate goal would be a lock-free, wait-free solution.
an example of where this might get used is the following interleaving of the audio and message thread. The goal is to keep the returned object from dangling
/*
AudioProcessor owns a SmartAtomicPtr<T> ptr that the message
thread has public access to.
*/
/* audio thread */ auto* t = ptr.getRaw();
/* message thread */ processor.ptr.update( new T() );
/* audio thread */ t->doSomething(); //t is a dangling pointer now
with getShared(), I believe that t no longer dangles:
/* audio thread */ auto t = ptr.getShared();
/* message thread */ processor.ptr.update( new T() );
/* audio thread */ t->doSomething(); //t is one of 2 shared_ptrs
//holding the previous atomic value of ptr
I ran into some double-deletes, but I believe I have solved them, and also prevented the shared_ptr member from being stomped on in the event you call getShared() and update() at the same time, and also kept it leak-free.
any thoughts?
c++ pointers audio lock-free atomic
c++ pointers audio lock-free atomic
edited 8 mins ago
200_success
130k16153417
asked 13 hours ago
MatkatMusicMatkatMusic
82
New contributor
MatkatMusic is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 8 mins ago
200_success
130k16153417
asked 13 hours ago
MatkatMusicMatkatMusic
82
New contributor
MatkatMusic is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 8 mins ago
200_success
130k16153417
edited 8 mins ago
200_success
130k16153417
edited 8 mins ago
200_success
130k16153417
130k16153417
asked 13 hours ago
MatkatMusicMatkatMusic
82
New contributor
MatkatMusic is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 13 hours ago
MatkatMusicMatkatMusic
82
asked 13 hours ago
MatkatMusicMatkatMusic
82
82
New contributor
MatkatMusic is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
MatkatMusic is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
MatkatMusic is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
From C++20, there'sstd::atomic<shared_ptr<T>>partial specialization. You'll want to understand how it works if you're implementing your own.
$endgroup$
– Toby Speight
9 hours ago
add a comment |
$begingroup$
From C++20, there'sstd::atomic<shared_ptr<T>>partial specialization. You'll want to understand how it works if you're implementing your own.
$endgroup$
– Toby Speight
9 hours ago
$begingroup$
From C++20, there's
std::atomic<shared_ptr<T>> partial specialization. You'll want to understand how it works if you're implementing your own.$endgroup$
– Toby Speight
9 hours ago
$begingroup$
From C++20, there's
std::atomic<shared_ptr<T>> partial specialization. You'll want to understand how it works if you're implementing your own.$endgroup$
– Toby Speight
9 hours ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
keepAlive.reset is not thread safe. So your class as a whole cannot be thread safe.
answered 11 hours ago
ratchet freakratchet freak
12k1344
$endgroup$
$begingroup$
Concrete proof that a short answer can be a great answer - good one!
$endgroup$
– Toby Speight
9 hours ago
add a comment |
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$begingroup$
keepAlive.reset is not thread safe. So your class as a whole cannot be thread safe.
answered 11 hours ago
ratchet freakratchet freak
12k1344
$endgroup$
$begingroup$
Concrete proof that a short answer can be a great answer - good one!
$endgroup$
– Toby Speight
9 hours ago
add a comment |
$begingroup$
keepAlive.reset is not thread safe. So your class as a whole cannot be thread safe.
answered 11 hours ago
ratchet freakratchet freak
12k1344
$endgroup$
$begingroup$
Concrete proof that a short answer can be a great answer - good one!
$endgroup$
– Toby Speight
9 hours ago
add a comment |
$begingroup$
keepAlive.reset is not thread safe. So your class as a whole cannot be thread safe.
answered 11 hours ago
ratchet freakratchet freak
12k1344
$endgroup$
keepAlive.reset is not thread safe. So your class as a whole cannot be thread safe.
answered 11 hours ago
ratchet freakratchet freak
12k1344
answered 11 hours ago
ratchet freakratchet freak
12k1344
answered 11 hours ago
ratchet freakratchet freak
12k1344
answered 11 hours ago
ratchet freakratchet freak
12k1344
12k1344
$begingroup$
Concrete proof that a short answer can be a great answer - good one!
$endgroup$
– Toby Speight
9 hours ago
add a comment |
$begingroup$
Concrete proof that a short answer can be a great answer - good one!
$endgroup$
– Toby Speight
9 hours ago
$begingroup$
Concrete proof that a short answer can be a great answer - good one!
$endgroup$
– Toby Speight
9 hours ago
$begingroup$
Concrete proof that a short answer can be a great answer - good one!
$endgroup$
– Toby Speight
9 hours ago
add a comment |
MatkatMusic is a new contributor. Be nice, and check out our Code of Conduct.
MatkatMusic is a new contributor. Be nice, and check out our Code of Conduct.
MatkatMusic is a new contributor. Be nice, and check out our Code of Conduct.
MatkatMusic is a new contributor. Be nice, and check out our Code of Conduct.
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$begingroup$
From C++20, there's
std::atomic<shared_ptr<T>>partial specialization. You'll want to understand how it works if you're implementing your own.$endgroup$
– Toby Speight
9 hours ago