Sponsored Content
Special Forums UNIX and Linux Applications High Performance Computing Memory Barriers for (Ubuntu) Linux (i686) Post 302430462 by Corona688 on Thursday 17th of June 2010 05:25:35 PM
Old 06-17-2010
P.S. On a two-core single-CPU system, the overhead of XCHG vs LOCK XCHG with five seperate processes:

Code:
$ ./a.out & ./a.out & ./a.out & ./a.out & ./a.out &
12225 !Lock     time = 0 M 8 S 657 ms 205 us = 0.116 Mops/s
12229 !Lock     time = 0 M 8 S 801 ms 676 us = 0.114 Mops/s
12227 !Lock     time = 0 M 8 S 896 ms 459 us = 0.112 Mops/s
12228 !Lock     time = 0 M 8 S 958 ms 739 us = 0.112 Mops/s
12226 !Lock     time = 0 M 9 S 157 ms 723 us = 0.109 Mops/s
12228 Lock      time = 0 M 8 S 610 ms 749 us = 0.116 Mops/s
12227 Lock      time = 0 M 8 S 719 ms 860 us = 0.115 Mops/s
12225 Lock      time = 0 M 9 S 49 ms 622 us = 0.111 Mops/s
12226 Lock      time = 0 M 8 S 608 ms 304 us = 0.116 Mops/s
12229 Lock      time = 0 M 9 S 48 ms 352 us = 0.111 Mops/s

The code is a million loops of this:
Code:
                        "LOOP1:                 \n"
                        "       xchg    %ebx, a \n"
                        "       xchg    %ebx, a \n"
                        "       xchg    %ebx, a \n"
                        "       xchg    %ebx, a \n"
                        "       xchg    %ebx, a \n"
                        "       loop    LOOP1   \n"

except once with LOCK XCHG, one with just XCHG. No significant difference.

---------- Post updated at 03:25 PM ---------- Previous update was at 03:14 PM ----------

Quote:
Originally Posted by gorga
I originally used it with existing thread-pools, but found I needed more control over the allocation of "tasks" to "cores"
How so?
Quote:
hence I'm making my own.
I don't see how using a different structure excludes pthreads. You wanted to avoid pthreads since it used atomic ops, and are prepared to use atomic ops instead? It's best to write portably if possible anyway.

Last edited by Corona688; 06-17-2010 at 06:42 PM..
 

4 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Memory-waste in Ubuntu/Debian?

I have 512 mem on this laptop, though 'top' tells me I only have 380. However, Ubuntu is using 288 mb of memory, when I only have 3 terminals, running lynx, vim(for this file) and (of course) top. Considering it I have lynx running a 600 page txt file, which of course would eat some memory but 300?... (0 Replies)
Discussion started by: riwa
0 Replies

2. Linux

i686, x86 64, ppc

Hi, i am quite new to linux. I am interested in fedora linux distro. Fedora Project I dont know which one to choose, either i686, x86 64 or ppc. I prefer a live cd, coz its easy to use. And what is the difference between "Fedora Desktop Live Media" and "Fedora KDE Live Media". (3 Replies)
Discussion started by: superblacksmith
3 Replies

3. Programming

Getting the total virtual memory for ubuntu in c++

Hi guys , i need to get the total virtual memory in ubuntu but i need to write a C++ code for that, any idea on how to go about doing it? any references? or website that i can refer to ? (6 Replies)
Discussion started by: xiaojesus
6 Replies

4. Ubuntu

XP and Linux (Ubuntu) on same disk, Can I install Ubuntu on not-yet partitioned portion of disk?

My PC (Esprimo, 3 yeas old) has one hard drive having 2 partitions C: (80 GB NTFS, XP) and D: (120 GB NTFS, empty) and and a 200 MB area that yet is not-partitioned. I would like to try Ubuntu and to install Ubuntu on the not-partitioned area . The idea is to have the possibility to run... (7 Replies)
Discussion started by: C.Weidemann
7 Replies
Apache::Session::Lock::Sybase(3pm)			User Contributed Perl Documentation			Apache::Session::Lock::Sybase(3pm)

NAME
Apache::Session::Lock::Sybase - Provides mutual exclusion using Sybase SYNOPSIS
use Apache::Session::Lock::Sybase; my $locker = new Apache::Session::Lock::Sybase; $locker->acquire_read_lock($ref); $locker->acquire_write_lock($ref); $locker->release_read_lock($ref); $locker->release_write_lock($ref); $locker->release_all_locks($ref); DESCRIPTION
Apache::Session::Lock::Sybase fulfills the locking interface of Apache::Session. Mutual exclusion is achieved through the use of Sybase's sp_getapplock and sp_releaseapplock functions. Sybase does not support the notion of read and write locks, so this module only supports exclusive locks. When you request a shared read lock, it is instead promoted to an exclusive write lock. CONFIGURATION
The module must know how to connect to your MySQL database to acquire locks. You must provide a datasource name, a user name, and a password. These options are passed in the usual Apache::Session style, and are very similar to the options for Apache::Session::Store::Sybase. Example: tie %hash, 'Apache::Session::Sybase', $id, { LockDataSource => 'dbi:sybase:database', LockUserName => 'database_user', LockPassword => 'K00l' }; Instead, you may pass in an already opened DBI handle to your database. tie %hash, 'Apache::Session::Sybase', $id, { LockHandle => $dbh }; AUTHOR
This module was written by Oliver Maul <oli@42.nu>. SEE ALSO
Apache::Session perl v5.10.1 2010-10-18 Apache::Session::Lock::Sybase(3pm)
All times are GMT -4. The time now is 07:00 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy