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I know this is a common problem and mutexes and semaphores provide in-built memory barriers to address this problem but I'm trying to build a scalable application and I want to avoid their use if possible. I also know GCC provides built-in atomic operations but I see they involve locking the data-bus, and I've heard about system primitives like "smp_wmb()" but I'm not sure how to incorporate these into my "user-space" program as they are platform dependent.
Therefore can anyone provide pointers or advise on how best (in terms of scalability and speed) to guarantee ordering is maintained?
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libmlib_mt(3LIB) Interface Libraries libmlib_mt(3LIB)NAME
libmlib_mt - multi-threaded mediaLib
SYNOPSIS
cc [ flag... ] file... -lmlib_mt-lmlib [ library... ]
#include <mlib.h>
DESCRIPTION
Interfaces in this library provide functions for multimedia processing. Multi-threaded (MT) mediaLib is a software layer developed on top
of mediaLib using OpenMP. When it is used with a large data set on a multi-processor system, MT mediaLib will partition data into subsets
and process the subsets in parallel, thus greatly improving performance of applications that use mediaLib.
INTERFACES
The shared object libmlib_mt.so.2 provides the same public interfaces as those defined in libmlib(3LIB). See Intro(3) for additional infor-
mation on shared object interfaces.
USAGE
There are two ways to use MT mediaLib.
1. Pre-load a multi-threaded mediaLib library during runtime by setting the LD_PRELOAD environment variable as follows before
starting your application, in Bourne/Korn shell:
LD_PRELOAD=libmlib_mt.so
export LD_PRELOAD
or in C shell:
setenv LD_PRELOAD libmlib_mt.so
In this way, you can take advantage of MT mediaLib without rebuilding your application.
2. Link your application with a multi-threaded mediaLib library directly as shown under SYNOPSIS. In this way, an MT mediaLib
library is always used whenever your application is started.
The parallelization of MT mediaLib is controlled, in part, by the PARALLEL environment variable. You can change its setting to adjust the
degree of parallelization before starting your application, in Bourne/Korn shell:
PARALLEL=n
export PARALLEL
or in C shell:
setenv PARALLEL n
where n is a positive integer for number of threads. Note that other factors also affect the degree of parallelization in MT mediaLib.
FILES
/usr/lib/libmlib_mt.so.2
shared object
/usr/lib/64/libmlib_mt.so.2
64-bit shared object
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWmlibt |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO Intro(3), libmlib(3LIB), attributes(5)
mediaLib User's Manual
SunOS 5.11 15 Oct 2007 libmlib_mt(3LIB)