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Special Forums UNIX and Linux Applications High Performance Computing Memory Barriers for (Ubuntu) Linux (i686) Post 302430730 by Corona688 on Friday 18th of June 2010 01:34:12 PM
Old 06-18-2010
The old system(usually known as linuxthreads) has been abandoned for many moons now. It was designed to operate without modifying the kernel, which made it a very strange beast -- it created pretend-thread processes with 100% shared memory, did all communication with signal traps, and had some very....unique bugs that turned out to be fundamental design flaws(zombie threads! Wow!)

So, no. It was not a high-performance threading model. There's only a very few things(like ulibc in embedded systems) that still stick with it these days.

With kernel 2.5 and later, they built enough things into the kernel to let them do threading properly. I've shown you bits of its code -- some fundamental things are almost down to the instruction level. NPTL is much, much better, and I've found it quite good.

Quote:
I wanted to avoid the pthreads syncrhonisation structures like mutexes because I sought to avoid their overhead and keep it scalable.
Yes, and the overhead you were worried about was the same atomic operations you're hellbent on using now. I've looked in its code and shown you some of it; it's not bloated.
Quote:
There are ways to distribute work such that mutexes aren't necessary as long as an ordering of instructions can be guaranteed, hence following your advice, I'll try those atomic instructions from GCC.
I remain stolidly unconvinced that spinlocking is more efficient than blocking. If your writer really can keep up with your readers, a proper queue might not block at all even in pthreads.
Quote:
But anyway, I needed something with more control than was on offer with something featuring a standard posix api.
Are you sure of that? You only discovered thread-specific data last week.

Last edited by Corona688; 06-18-2010 at 02:42 PM..
 

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PPI::Token::QuoteLike(3)				User Contributed Perl Documentation				  PPI::Token::QuoteLike(3)

NAME
PPI::Token::QuoteLike - Quote-like operator abstract base class INHERITANCE
PPI::Token::QuoteLike isa PPI::Token isa PPI::Element DESCRIPTION
The "PPI::Token::QuoteLike" class is never instantiated, and simply provides a common abstract base class for the five quote-like operator classes. In PPI, a "quote-like" is the set of quote-like things that exclude the string quotes and regular expressions. The subclasses of "PPI::Token::QuoteLike" are: qw{} - PPI::Token::QuoteLike::Words `` - PPI::Token::QuoteLike::Backtick qx{} - PPI::Token::QuoteLike::Command qr// - PPI::Token::QuoteLike::Regexp <FOO> - PPI::Token::QuoteLike::Readline The names are hopefully obvious enough not to have to explain what each class is. See their pages for more details. You may note that the backtick and command quote-like are treated separately, even though they do the same thing. This is intentional, as the inherit from and are processed by two different parts of the PPI's quote engine. SUPPORT
See the support section in the main module. AUTHOR
Adam Kennedy <adamk@cpan.org> COPYRIGHT
Copyright 2001 - 2011 Adam Kennedy. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of the license can be found in the LICENSE file included with this module. perl v5.18.2 2011-02-25 PPI::Token::QuoteLike(3)
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