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Re: Why is java consumer/producer so much faster than C++

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On Mon, 23 Jul 2012 02:03:28 +0200
Luca Risolia <luca.risolia@studio.unibo.it> wrote:

> On 23/07/2012 01:28, Melzzzzz wrote:
> > Still twice as fast as c++.
> > What it looks like, is that c++ spends much more time in syscalls
> > (futex) than java and that explains big difference.
> 
> A lock-free "BlockingQueue" would probably be more efficient.
> You can also try to implement your Queue with std::array instead of 
> std::deque and see how it performs.

I will try. Seems that java ArrayBlockingQueue is more efficient
because if that. 

> 
> In the C++ version change:
> 
> 	while (queue_.size() >= capacity_)c_full_.wait(lock);
> with
> 	c_full_.wait(lock, [this]{return queue_.size() < capacity_;});
> 
> and
> 	while (queue_.empty())c_empty_.wait(lock);
> with
> 	c_empty_.wait(lock, [this]{return !queue_.empty();});
> 
> Also use a std::lock_guard in empty() instead of std::unique_lock.
> The former is faster.

Yes, I got speed up of few seconds, thanks.

> 
> (On a side note, the C++ version you have given does not have the
> best possible interface for a thread-safe queue)

I have just copied Java BlockingQueue interface, which is of course
suited for Java. Don't know actually how ideal interface would look
like.


> 

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Thread

Why is java consumer/producer so much faster than C++ Melzzzzz <mel@zzzzz.com> - 2012-07-22 23:59 +0200
  Re: Why is java consumer/producer so much faster than C++ Joshua Maurice <joshuamaurice@gmail.com> - 2012-07-22 15:42 -0700
    Re: Why is java consumer/producer so much faster than C++ Melzzzzz <mel@zzzzz.com> - 2012-07-23 01:28 +0200
      Re: Why is java consumer/producer so much faster than C++ Luca Risolia <luca.risolia@studio.unibo.it> - 2012-07-23 02:03 +0200
        Re: Why is java consumer/producer so much faster than C++ Melzzzzz <mel@zzzzz.com> - 2012-07-23 12:17 +0200
          Re: Why is java consumer/producer so much faster than C++ Luca Risolia <luca.risolia@studio.unibo.it> - 2012-07-24 00:33 +0200
  Re: Why is java consumer/producer so much faster than C++ Juha Nieminen <nospam@thanks.invalid> - 2012-07-23 06:37 +0000
    Re: Why is java consumer/producer so much faster than C++ Melzzzzz <mel@zzzzz.com> - 2012-07-23 12:33 +0200
      Re: Why is java consumer/producer so much faster than C++ Juha Nieminen <nospam@thanks.invalid> - 2012-07-23 11:46 +0000
        Re: Why is java consumer/producer so much faster than C++ Melzzzzz <mel@zzzzz.com> - 2012-07-23 15:33 +0200
  Re: Why is java consumer/producer so much faster than C++ Dombo <dombo@disposable.invalid> - 2012-07-23 22:57 +0200
    Re: Why is java consumer/producer so much faster than C++ Joshua Maurice <joshuamaurice@gmail.com> - 2012-07-23 21:54 -0700
      Re: Why is java consumer/producer so much faster than C++ Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-07-24 12:50 +0000
  Re: Why is java consumer/producer so much faster than C++ Ricardo Nabinger Sanchez <rnsanchez@wait4.org> - 2012-08-14 22:48 +0000

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