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Comments (33)

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  bheadmaster
  > NOTE: Throughout our implementation we strictly use compare_exchange_strong, but the C++ standard suggests that for some systems like ARM it mighe be a better idea to run a loop with compare_exchange_weak for better performance. The problem with that is a compare_exchange_weak call may fail spuriously, which essentially it can randomly fail even if everything is correct, thus it makes code code a bit more complicated, so I avoided it for this implementation.The reason using `compare_exchange_weak` is a better idea for lock-free algorithms is that, in most cases, you'll run it in a retry loop anyway. Since `compare_exchange_strong` is compiled to a retry loop, if you do a retry loop of `compare_exchange_strong` you basically have a loop in a loop. Using `compare_exchange_weak` makes things both simpler and more performant.
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  moffers
  Not trying to be critical, but there are a number of misspellings and grammatical issues and it was actually a breath of fresh air to be reminded while I was reading that a real human being wrote this. I feel a little inspired to turn off spell check for my own writing.
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  rfgplk
  Nice article. There a few issues with your code however from a cursory glance; your dtor seems to allow for spurious/double frees due to custom deleter support (you wanna check up on that), you also seem to use seq_cst far too much even if not needed (you want to avoid them is queues as much as possible), lastly class FastQueueNodeSlot.. isn't aligned (plus 64b alignment is only a thing for amd64 cpus, apple silicon is larger).
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  nly
  Once you use atomic cmpxchg you've lost a great deal of scalability because it implies a retry loop (internal or by the user)The last thing you want is all of the threads failing to cmpxchg (spuriously or otherwise ) spinning on a shared cachelineReal world alternatives show atomic xchg only solutions scale to hundreds of threads.
• usefulcat
  I would have thought that std::optional would have been a likely candidate for use with the Pop() method?
• PcChip
  Is this similar to moodycamel’s?
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  brcmthrowaway
  How can I make a lock free queue without OS support, ESP32?
• jeffbee
  Whether the allocator calls are "naive" or not depends entirely on the allocator in use. If you need thread/core locality and batching you can get that by replacing global new/delete functions with a decent allocator.