| |
| This documentation tries to help people who intend to use Python on |
| AIX. |
| |
| There used to be many issues with Python on AIX, but the major ones |
| have been corrected for version 3.2, so that Python should now work |
| rather well on this platform. The remaining known issues are listed in |
| this document. |
| |
| |
| ====================================================================== |
| Compiling Python |
| ---------------------------------------------------------------------- |
| |
| You can compile Python with gcc or the native AIX compiler. The native |
| compiler used to give better performances on this system with older |
| versions of Python. With Python 3.2 it may not be the case anymore, |
| as this compiler does not allow compiling Python with computed gotos. |
| Some benchmarks need to be done. |
| |
| Compiling with gcc: |
| |
| cd Python-3.2 |
| CC=gcc OPT="-O2" ./configure --enable-shared |
| make |
| |
| There are various aliases for the native compiler. The recommended |
| alias for compiling Python is 'xlc_r', which provides a better level of |
| compatibility and handles thread initialization properly. |
| |
| It is a good idea to add the '-qmaxmem=70000' option, otherwise the |
| compiler considers various files too complex to optimize. |
| |
| Compiling with xlc: |
| |
| cd Python-3.2 |
| CC=xlc_r OPT="-O2 -qmaxmem=70000" ./configure --without-computed-gotos --enable-shared |
| make |
| |
| |
| ====================================================================== |
| Memory Limitations |
| ---------------------------------------------------------------------- |
| |
| Note: this section may not apply when compiling Python as a 64 bit |
| application. |
| |
| By default on AIX each program gets one segment register for its data |
| segment. As each segment register covers 256 MiB, a Python program that |
| would use more than 256 MiB will raise a MemoryError. The standard |
| Python test suite is one such application. |
| |
| To allocate more segment registers to Python, you must use the linker |
| option -bmaxdata or the ldedit tool to specify the number of bytes you |
| need in the data segment. |
| |
| For example, if you want to allow 512 MiB of memory for Python (this is |
| enough for the test suite to run without MemoryErrors), you should run |
| the following command at the end of compilation: |
| |
| ldedit -b maxdata:0x20000000 ./python |
| |
| You can allow up to 2 GiB of memory for Python by using the value |
| 0x80000000 for maxdata. |
| |
| It is also possible to go beyond 2 GiB of memory by activating Large |
| Page Use. You should consult the IBM documentation if you need to use |
| this option. You can also follow the discussion of this problem |
| in issue 11212 at bugs.python.org. |
| |
| http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.cmds/doc/aixcmds3/ldedit.htm |
| |
| |
| ====================================================================== |
| Known issues |
| ---------------------------------------------------------------------- |
| |
| Those issues are currently affecting Python on AIX: |
| |
| * Python has not been fully tested on AIX when compiled as a 64 bit |
| application. |
| |
| * issue 3526: the memory used by a Python process will never be |
| released to the system. If you have a Python application on AIX that |
| uses a lot of memory, you should read this issue and you may |
| consider using the provided patch that implements a custom malloc |
| implementation |
| |
| * issue 11192: test_socket fails |
| |
| * issue 11190: test_locale fails |
| |
| * issue 11193: test_subprocess fails |
| |
| * issue 9920: minor arithmetic issues in cmath |
| |
| * issue 11215: test_fileio fails |
| |
| |
| |
| ====================================================================== |
| Implementation details for developers |
| ---------------------------------------------------------------------- |
| |
| Python and python modules can now be built as shared libraries on AIX |
| as usual. |
| |
| AIX shared libraries require that an "export" and "import" file be |
| provided at compile time to list all extern symbols which may be |
| shared between modules. The "export" file (named python.exp) for the |
| modules and the libraries that belong to the Python core is created by |
| the "makexp_aix" script before performing the link of the python |
| binary. It lists all global symbols (exported during the link) of the |
| modules and the libraries that make up the python executable. |
| |
| When shared library modules (.so files) are made, a second shell |
| script is invoked. This script is named "ld_so_aix" and is also |
| provided with the distribution in the Modules subdirectory. This |
| script acts as an "ld" wrapper which hides the explicit management of |
| "export" and "import" files; it adds the appropriate arguments (in the |
| appropriate order) to the link command that creates the shared module. |
| Among other things, it specifies that the "python.exp" file is an |
| "import" file for the shared module. |
| |
| This mechanism should be transparent. |