1 2 This documentation tries to help people who intend to use Python on 3 AIX. 4 5 There used to be many issues with Python on AIX, but the major ones 6 have been corrected for version 3.2, so that Python should now work 7 rather well on this platform. The remaining known issues are listed in 8 this document. 9 10 11 ====================================================================== 12 Compiling Python 13 ---------------------------------------------------------------------- 14 15 You can compile Python with gcc or the native AIX compiler. The native 16 compiler used to give better performances on this system with older 17 versions of Python. With Python 3.2 it may not be the case anymore, 18 as this compiler does not allow compiling Python with computed gotos. 19 Some benchmarks need to be done. 20 21 Compiling with gcc: 22 23 cd Python-3.2 24 CC=gcc OPT="-O2" ./configure --enable-shared 25 make 26 27 There are various aliases for the native compiler. The recommended 28 alias for compiling Python is 'xlc_r', which provides a better level of 29 compatibility and handles thread initialization properly. 30 31 It is a good idea to add the '-qmaxmem=70000' option, otherwise the 32 compiler considers various files too complex to optimize. 33 34 Compiling with xlc: 35 36 cd Python-3.2 37 CC=xlc_r OPT="-O2 -qmaxmem=70000" ./configure --without-computed-gotos --enable-shared 38 make 39 40 Note: 41 On AIX 5.3 and earlier, you will also need to specify the 42 "--disable-ipv6" flag to configure. This has been corrected in AIX 43 6.1. 44 45 46 ====================================================================== 47 Memory Limitations 48 ---------------------------------------------------------------------- 49 50 Note: this section may not apply when compiling Python as a 64 bit 51 application. 52 53 By default on AIX each program gets one segment register for its data 54 segment. As each segment register covers 256 MB, a Python program that 55 would use more than 256MB will raise a MemoryError. The standard 56 Python test suite is one such application. 57 58 To allocate more segment registers to Python, you must use the linker 59 option -bmaxdata or the ldedit tool to specify the number of bytes you 60 need in the data segment. 61 62 For example, if you want to allow 512MB of memory for Python (this is 63 enough for the test suite to run without MemoryErrors), you should run 64 the following command at the end of compilation: 65 66 ldedit -b maxdata:0x20000000 ./python 67 68 You can allow up to 2GB of memory for Python by using the value 69 0x80000000 for maxdata. 70 71 It is also possible to go beyond 2GB of memory by activating Large 72 Page Use. You should consult the IBM documentation if you need to use 73 this option. You can also follow the discussion of this problem 74 in issue 11212 at bugs.python.org. 75 76 http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.cmds/doc/aixcmds3/ldedit.htm 77 78 79 ====================================================================== 80 Known issues 81 ---------------------------------------------------------------------- 82 83 Those issues are currently affecting Python on AIX: 84 85 * Python has not been fully tested on AIX when compiled as a 64 bit 86 application. 87 88 * issue 3526: the memory used by a Python process will never be 89 released to the system. If you have a Python application on AIX that 90 uses a lot of memory, you should read this issue and you may 91 consider using the provided patch that implements a custom malloc 92 implementation 93 94 * issue 11184: support for large files is currently broken 95 96 * issue 11185: os.wait4 does not behave correctly with option WNOHANG 97 98 * issue 1745108: there may be some problems with curses.panel 99 100 * issue 11192: test_socket fails 101 102 * issue 11190: test_locale fails 103 104 * issue 11193: test_subprocess fails 105 106 * issue 9920: minor arithmetic issues in cmath 107 108 * issue 11215: test_fileio fails 109 110 * issue 11188: test_time fails 111 112 113 ====================================================================== 114 Implementation details for developers 115 ---------------------------------------------------------------------- 116 117 Python and python modules can now be built as shared libraries on AIX 118 as usual. 119 120 AIX shared libraries require that an "export" and "import" file be 121 provided at compile time to list all extern symbols which may be 122 shared between modules. The "export" file (named python.exp) for the 123 modules and the libraries that belong to the Python core is created by 124 the "makexp_aix" script before performing the link of the python 125 binary. It lists all global symbols (exported during the link) of the 126 modules and the libraries that make up the python executable. 127 128 When shared library modules (.so files) are made, a second shell 129 script is invoked. This script is named "ld_so_aix" and is also 130 provided with the distribution in the Modules subdirectory. This 131 script acts as an "ld" wrapper which hides the explicit management of 132 "export" and "import" files; it adds the appropriate arguments (in the 133 appropriate order) to the link command that creates the shared module. 134 Among other things, it specifies that the "python.exp" file is an 135 "import" file for the shared module. 136 137 This mechanism should be transparent. 138
