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diff --git a/docs/README.THREADS b/docs/README.THREADS new file mode 100644 index 0000000000..dbf612ba2d --- /dev/null +++ b/docs/README.THREADS @@ -0,0 +1,66 @@ + +NOTE: this information is obsolete for Mesa 3.1. Due to the big +changes in the Mesa code, the threads support is out of date. +Someone will have to review/update it. + + +Mesa Threads README +------------------- + +Mesa 2.6 is the starting point for an effort to make Mesa +safe in multithreaded applications. The files src/mthreads.c and +src/mthreads.h provide a platform independent threads API which Mesa +uses internally to provide thread-safe operation. At present the mthreads +code supports three thread APIS: + 1) POSIX threads (aka pthreads). + 2) Solaris / Unix International threads. + 3) Win32 threads (Win 95/NT). + +Here's the current list of targets which enable multithreaded handling +in Mesa: + + linux-386-pthread for Linux w/ Intel assembly and linuxthreads + sunos5-thread for Suns with SunOS 5.x, using Solaris threads + sunos5-pthread for Suns with SunOS 5.[56] using POSIX threads + sunos5-gcc-thread for Suns with SunOS 5.x and GCC, using Solaris threads + sunos5-gcc-pthread for Suns with SunOS 5.[56] and GCC, using POSIX threads + +In order to use Mesa with a multithreaded application, Mesa must be compiled +using one of the thread-enabled configurations. In cases where a platform +supports multiple APIs which are acceptable to Mesa, Mesa must be built +with the same threads API as the application in order for things to work +properly. For example, Solaris >= 2.5 support both POSIX threads and +Sun's own threads API. In order to guarantee proper operation, it is +necessary for both Mesa and application code to use the same threads API. +So, if your application uses Sun's thread API, then you should build Mesa +using one of the targets for Sun threads. + +Since this effort is still very much a work in progress, not all +aspects of Mesa are thread safe. As of this release (Mesa 2.6) only the +osmesa drivers have been made MT-safe. As work continues, other drivers +such as the X11 drivers will also incorporate MT-safe features. + +The mtdemos directory contains some example programs which use +multiple threads to render to osmesa rendering context(s). + +Linux users should be aware that there exist many different POSIX +threads packages. The best solution is the linuxthreads package +(http://pauillac.inria.fr/~xleroy/linuxthreads/) as this package is the +only one that really supports multiprocessor machines (AFAIK). See +http://pauillac.inria.fr/~xleroy/linuxthreads/README for further +information about the usage of linuxthreads. + +If you are interested in helping develop MT-safe Mesa, please send email +to j.stone@acm.org and poliwoda@volumegraphics.com who are the two most +directly involved in this effort currently. Similarly, if you have problems +using the MT-safe builds of Mesa, please send us comments/bugs etc. + +Future versions of Mesa will include more extensive documentation related +to multithreading. This is the first release of our work, so please bear +with us. + +Regards, + John Stone -- j.stone@acm.org johns@cs.umr.edu + Christoph Poliwoda -- poliwoda@volumegraphics.com + + |