67 lines
3.0 KiB
Plaintext
67 lines
3.0 KiB
Plaintext
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NOTE: this information is obsolete for Mesa 3.1. Due to the big
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changes in the Mesa code, the threads support is out of date.
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Someone will have to review/update it.
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Mesa Threads README
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-------------------
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Mesa 2.6 is the starting point for an effort to make Mesa
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safe in multithreaded applications. The files src/mthreads.c and
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src/mthreads.h provide a platform independent threads API which Mesa
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uses internally to provide thread-safe operation. At present the mthreads
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code supports three thread APIS:
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1) POSIX threads (aka pthreads).
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2) Solaris / Unix International threads.
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3) Win32 threads (Win 95/NT).
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Here's the current list of targets which enable multithreaded handling
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in Mesa:
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linux-386-pthread for Linux w/ Intel assembly and linuxthreads
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sunos5-thread for Suns with SunOS 5.x, using Solaris threads
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sunos5-pthread for Suns with SunOS 5.[56] using POSIX threads
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sunos5-gcc-thread for Suns with SunOS 5.x and GCC, using Solaris threads
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sunos5-gcc-pthread for Suns with SunOS 5.[56] and GCC, using POSIX threads
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In order to use Mesa with a multithreaded application, Mesa must be compiled
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using one of the thread-enabled configurations. In cases where a platform
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supports multiple APIs which are acceptable to Mesa, Mesa must be built
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with the same threads API as the application in order for things to work
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properly. For example, Solaris >= 2.5 support both POSIX threads and
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Sun's own threads API. In order to guarantee proper operation, it is
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necessary for both Mesa and application code to use the same threads API.
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So, if your application uses Sun's thread API, then you should build Mesa
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using one of the targets for Sun threads.
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Since this effort is still very much a work in progress, not all
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aspects of Mesa are thread safe. As of this release (Mesa 2.6) only the
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osmesa drivers have been made MT-safe. As work continues, other drivers
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such as the X11 drivers will also incorporate MT-safe features.
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The mtdemos directory contains some example programs which use
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multiple threads to render to osmesa rendering context(s).
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Linux users should be aware that there exist many different POSIX
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threads packages. The best solution is the linuxthreads package
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(http://pauillac.inria.fr/~xleroy/linuxthreads/) as this package is the
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only one that really supports multiprocessor machines (AFAIK). See
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http://pauillac.inria.fr/~xleroy/linuxthreads/README for further
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information about the usage of linuxthreads.
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If you are interested in helping develop MT-safe Mesa, please send email
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to j.stone@acm.org and poliwoda@volumegraphics.com who are the two most
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directly involved in this effort currently. Similarly, if you have problems
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using the MT-safe builds of Mesa, please send us comments/bugs etc.
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Future versions of Mesa will include more extensive documentation related
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to multithreading. This is the first release of our work, so please bear
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with us.
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Regards,
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John Stone -- j.stone@acm.org johns@cs.umr.edu
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Christoph Poliwoda -- poliwoda@volumegraphics.com
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