Re: [boost] [lockfree::fifo] Review

Subject: Re: [boost] [lockfree::fifo] Review
From: Chris M. Thomasson (cristom_at_[hidden])
Date: 2009-12-18 05:52:40

"Chris M. Thomasson" <cristom_at_[hidden]> wrote in message 
news:hgfmj4$8m0$1_at_ger.gmane.org...
> "Tim Blechmann" <tim_at_[hidden]> wrote in message
> news:4B23A083.7080008_at_klingt.org...
>
>> >> i just went through the replies ... (maybe i should upcase some parts
>> >> in
>> >> the documentation, that the implementation focus on WORST CASE, not
>> >> AVERAGE CASE performance ... people keep complaining that the
>> >> stack/fifo
>> >> may be outperformed be blocking algorithms, which is both true and
>> >> irrelevant for me, as these implementations are soft real-time safe
>> >> (and
>> >> could be made hard real-time safe).
>> >
>> > Agreed.
>> > Are you planning to augment your library with algorithms for different
>> > needs? Like MPSC, SPMC and so forth? I think that could be useful,
>> > because it looks like implementing the most generic MPMC case won't 
>> > give
>> > you the best results.
>
>> i just added a lock-free single-producer/single-consumer ringbuffer to
>> my git repository, branch topic/spsc_ringbuffer ... it implements an
>> algorithm, that is commonly found in open source audio applications ...
>> performs about 8 times faster than the m-s fifo queue (which is based on
>> linked lists).
>
> FWIW Tim, here is a very simple pseudo-code implementation of a nice
> single-producer/consumer bounded queue:
> _______________________________________________________________
> template<template T,
>                size_t T_depth>
> class spsc_queue
> {
>    atomic<T*> m_buffer[T_depth]; // = { NULL }
>    size_t m_head; // = 0
>    size_t m_tail; // = 0
>
>
>
> public:
>    bool push(T* object)
>    {
>        if (m_buffer[m_head].load(memory_order_relaxed))
>        {
>            return false;
>        }
>
>        m_buffer[m_head].store(memory_order_release);

Ummm, that should be

         m_buffer[m_head].store(object, memory_order_release);

of course!!!

Sorry about that.