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PE_ENVIRON(5) Last changed: 3-10-98 NNAAMMEE ppee__eennvviirroonn - Programming environment variables IIMMPPLLEEMMEENNTTAATTIIOONN IRIX systems DDEESSCCRRIIPPTTIIOONN This man page describes environment variables used when developing and running MIPSpro 7 Fortran 90 programs on IRIX systems. The environment variables are grouped by function and platform. OOPPEENNMMPP FFOORRTTRRAANN AAPPII VVAARRIIAABBLLEESS The following environment variables are defined in the OpenMP Fortran API. VVaarriiaabbllee EEffffeecctt oonn ssyysstteemm OOMMPP__SSCCHHEEDDUULLEE Sets the schedule type and (optionally) the chunk size for DDOO and PPAARRAALLLLEELL DDOO loops declared with a schedule of RRUUNNTTIIMMEE. For these loops, the schedule is set at run time when the system reads the value of this environment variable. Valid values for this environment variable are SSTTAATTIICC, DDYYNNAAMMIICC, and GGUUIIDDEEDD. The default value for this environment variable is SSTTAATTIICC. For DDOO and PPAARRAALLLLEELL DDOO directives that have a schedule type other than RRUUNNTTIIMMEE, this environment variable is ignored. If the optional chunk size is not set, a chunk size of 1 is assumed, except in the case of a SSTTAATTIICC schedule. For a SSTTAATTIICC schedule, the default chunk size is set to the loop iteration space divided by the number of threads applied to the loop. Examples: setenv OMP_SCHEDULE "GUIDED,4" setenv OMP_SCHEDULE "dynamic" OOMMPP__NNUUMM__TTHHRREEAADDSS Sets the number of threads to use during execution, unless that number is explicitly changed by calling the OOMMPP__SSEETT__NNUUMM__TTHHRREEAADDSS(3) subroutine. When dynamic adjustment of the number of threads is enabled, the value of this environment variable is the maximum number of threads to use. The default value is the minimum of 8 and the number of CPUs on the system. Example: setenv OMP_NUM_THREADS 16 OOMMPP__DDYYNNAAMMIICC Enables or disables dynamic adjustment of the number of threads available for execution of parallel regions. If set to TTRRUUEE, the number of threads that are used for executing parallel regions can be adjusted by the run time environment to best utilize system resources. The default value is TTRRUUEE. If set to FFAALLSSEE, dynamic adjustment is disabled. Example: setenv OMP_DYNAMIC TRUE OOMMPP__NNEESSTTEEDD Enables or disables nested parallelism. If set to TTRRUUEE, nested parallelism is enabled. If it is set to FFAALLSSEE, it is disabled. Default. Example: setenv OMP_NESTED TRUE OORRIIGGIINN SSEERRIIEESS VVAARRIIAABBLLEESS The following environment variables are recognized on Origin 2000, Origin 200, and Cray Origin 2000 systems. VVaarriiaabbllee EEffffeecctt oonn ssyysstteemm __DDSSMM__BBAARRRRIIEERR Controls the barrier implementation within the MP run-time system. This environment variable accepts one of the following values: VVaalluuee AAccttiioonn FFOOPP Uses the uncached operations available on Origin series systems. FFOOPP achieves the best performance. This requires kernel patch #1856. LLLLSSCC Uses load-linked (LL), store-conditional (SC) operations on shared memory. SSHHMM Uses regular shared memory. Default. __DDSSMM__MMIIGGRRAATTIIOONN Specifies aspects of automatic page migration. This environment variable accepts one of the following values: VVaalluuee AAccttiioonn OOFFFF Disables migration. Default. OONN Enables migration for all but explicitly placed data (using PPAAGGEE__PPLLAACCEE or a data distribution directive). AALLLL__OONN Enables migration for all data. __DDSSMM__MMIIGGRRAATTIIOONN__LLEEVVEELL Controls the aggressiveness level of automatic page migration. This environment variable must be set to an integer value between 0 (most conservative setting) and 100 (most aggressive). Specifying 0 disables this feature. The default setting is 100. __DDSSMM__MMUUSSTTRRUUNN Locks each thread to the corresponding CPU. This environment variable is not set by default. __DDSSMM__OOFFFF When set to OFF, disables nonuniform memory access (NUMA) calls. This can be used, for example, to allocate pages from a particular memory. On Origin series systems, __DDSSMM__OOFFFF is set to ON by default. This environment variable is not set by default. __DDSSMM__PPLLAACCEEMMEENNTT Allocates memory for all stack, data, and text segments. This environment variable accepts the following values: VVaalluuee AAccttiioonn FFIIRRSSTT__TTOOUUCCHH Specifies first-touch data placement. Default. RROOUUNNDD__RROOBBIINN Specifies round-robin data allocation. __DDSSMM__PPPPMM Specifies the number of processors to use per memory module. Must be set to an integer value. To use only one processor per memory module, set this environment variable to 1. __DDSSMM__VVEERRBBOOSSEE When set, writes messages to ssttddoouutt about parameters used during execution to ssttddoouutt. __DDSSMM__WWAAIITT Controls how a thread waits for a synchronization event, such as a lock or a barrier. This environment variable accepts one of the following values: VVaalluuee AAccttiioonn SSPPIINN Specifies that a thread wait in a loop until the synchronization event succeeds. YYIIEELLDD Specifies that a waiting thread should spin for a while and invokes ssggiinnaapp(2). This surrenders the CPU to another waiting process (if any). Default. MMUULLTTIIPPRROOCCEESSSSIINNGG VVAARRIIAABBLLEESS The multiprocessing environment variables allow you to set up your multiprocessing environment. Some of the settings that these environment variables control can also be set through library routines. For more information on the multiprocessing library routines, see MMPP(3F). NNOOTTEE:: Many of the environment variables in the following list are outmoded. The descriptions for each one indicate the preferred alternative, if one exists. VVaarriiaabbllee EEffffeecctt oonn ssyysstteemm MMPP__SSEETT__NNUUMMTTHHRREEAADDSS, MMPP__BBLLOOCCKKTTIIMMEE, MMPP__SSEETTUUPP, and NNUUMM__TTHHRREEAADDSS Acts as an implicit call to the following library routines: MMPP__SSEETT__NNUUMMTTHHRREEAADDSS(3F), MMPP__BBLLOOCCKKTTIIMMEE(3F), and MMPP__SSEETTUUPP(3F) (respectively). The MMPP__SSEETT__NNUUMMTTHHRREEAADDSS environment variable determines the number of processors across which an array is distributed during program execution, regardless of the number of processors physically present on the machine. As its value, MMPP__SSEETT__NNUUMMTTHHRREEAADDSS accepts one of the following: an integer between 1 and the number of CPUs on your system; an integer expression that includes the symbols ++, --, mmiinn, and mmaaxx; and the special keyword aallll. The keyword aallll refers to the total number of CPUs on the machine. The default is either the number of CPUs on your system or 8. MMPP__BBLLOOCCKKTTIIMMEE accepts an integer value. MMPP__SSEETTUUPP accepts no values. Example 1. The following two specifications prevent the slave threads from autoblocking: sseett MMPP__BBLLOOCCKKTTIIMMEE 00 (for sshh) CCAALLLL MMPP__BBLLOOCCKKTTIIMMEE ((00)) (library call) Example 2. The following setting selects the number of threads to be two fewer than the total number of CPUs but always at least one: sseetteennvv MMPP__SSEETT__NNUUMMTTHHRREEAADDSS mmaaxx((11,,aallll--22)) (for ccsshh) NNOOTTEE:: The MMPP__SSEETT__NNUUMMTTHHRREEAADDSS and NNUUMM__TTHHRREEAADDSS environment variables are outmoded. The preferred alternative is the OOMMPP__SSEETT__NNUUMMTTHHRREEAADDSS environment variable. MMPP__SSIIMMPPLLEE__SSCCHHEEDD Controls simple scheduling of parallel loops. This environment variable accepts the following values: VVaalluuee AAccttiioonn EEQQUUAALL Distributes iterations as equally as possible across the processors. BBLLOOCCKK Distributes iterations in a BBLLOOCCKK distribution. If you are using distributed arrays, the default BBLLOOCCKK. For all other cases, the default is EEQQUUAALL. The critical path (that is, the largest piece of the iteration space) is the same in either case. MMPP__SSUUGGNNUUMMTTHHDD and MMPPCC__SSUUGGNNUUMMTTHHDD Enables an additional, asynchronous process that monitors the system load. This environment variable may be useful on a system with long-running jobs and varying workloads. The process that is enabled allows you to vary the number of threads during execution of some jobs. When idle processors exist, the number of threads is increased, up to the maximum specified by MMPP__SSEETT__NNUUMMTTHHRREEAADDSS. When the system load increases, the number of threads is decreased, possibly to as few as one. Note that the number of threads being used is adjusted only at the start of a parallel region (for example, at a DDOOAACCRROOSSSS directive); it is not adjusted within a parallel region. Using this environment variable can improve overall system throughput. By avoiding excessive concurrency, this feature can reduce delays at synchronization points within a single application. These environment variables are on by default. NNOOTTEE:: The MMPP__SSUUGGNNUUMMTTHHDD and MMPPCC__SSUUGGNNUUMMTTHHDD environment variables are outmoded. The preferred alternative is the OOMMPP__DDYYNNAAMMIICC environment variable. MMPP__SSUUGGNNUUMMTTHHDD__MMIINN and MMPP__SSUUGGNNUUMMTTHHDD__MMAAXX Limits the effect of MMPP__SSUUGGNNUUMMTTHHDD. These environment variables accept an integer value between 1 and the value of MMPP__SSEETT__NNUUMMTTHHRREEAADDSS. When these environment variables are set, the number of processors is not lowered below the MMPP__SSUUGGNNUUMMTTHHDD__MMIINN setting and it is not increased beyond the MMPP__SSUUGGNNUUMMTTHHDD__MMAAXX setting. NNOOTTEE:: The MMPP__SSUUGGNNUUMMTTHHDD__MMIINN and MMPP__SSUUGGNNUUMMTTHHDD__MMAAXX environment variables are outmoded. MMPP__SSUUGGNNUUMMTTHHDD__VVEERRBBOOSSEE Determines whether or not the system writes informational messages to ssttddeerrrr whenever the process changes the number of threads in use. The compiler interprets library calls to MMPP__NNUUMMTTHHRREEAADDSS(3F) and MMPP__SSEETT__NNUUMMTTHHRREEAADDSS(3F) as a sign that the application depends on the number of threads in use, and the number is frozen upon encountering either of these calls. If MMPP__SSUUGGNNUUMMTTHHDD__VVEERRBBOOSSEE is set, a message to that effect is written to ssttddeerrrr. By default, this environment variable is not set. NNOOTTEE:: The MMPP__SSUUGGNNUUMMTTHHDD__VVEERRBBOOSSEE environment variable is outmoded. The preferred alternative is the __DDSSMM__VVEERRBBOOSSEE environment variable. MMPP__SSTTAACCKK__SSLLAAVVEESSIIZZEE Controls the stack size of slave processes. As its value, it accepts an integer number that indicates the desired stack size, in bytes. The default is 16 Mbytes (4 Mbytes for greater than 64 threads). Slave processes allocate their local data only onto their stacks. Shared data, even if allocated on the master's stack, is not counted. MMPP__SSCCHHEEDDTTYYPPEE and CCHHUUNNKK Specifies the type of scheduling to use on PPAARRAALLLLEELL DDOO loops with scheduling specified as RRUUNNTTIIMMEE. The defaults are the same as those for the DDOOAACCRROOSSSS directive clauses. If neither environment variable is set, SSIIMMPPLLEE scheduling is assumed. If MMPP__SSCCHHEEDDTTYYPPEE is set and CCHHUUNNKK is not set, a CCHHUUNNKK of 1 is assumed. If CCHHUUNNKK is set, but MMPP__SSCCHHEEDDTTYYPPEE is not set, DDYYNNAAMMIICC scheduling is assumed. Example 1: To set the scheduing to IINNTTEERRLLEEAAVVEE, specify the following (in the ccsshh environment): setenv MP_SCHEDTYPE INTERLEAVE Example 2. To set the chunk size to 4, specify the following (ccsshh): setenv CHUNK 4 For more information on the DDOOAACCRROOSSSS directive, see the _M_I_P_S_P_r_o _7 _F_o_r_t_r_a_n _9_0 _C_o_m_m_a_n_d_s _a_n_d _D_i_r_e_c_t_i_v_e_s _R_e_f_e_r_e_n_c_e _M_a_n_u_a_l, publication SR-3907. NNOOTTEE:: The MMPP__SSCCHHEEDDTTYYPPEE and CCHHUUNNKK environment variables are outmoded. The preferred alternative is the OOMMPP__SSCCHHEEDDUULLEE environment variable. MMPPCC__GGAANNGG Controls the use of gang scheduling, which is enabled by default. To disable gang scheduling, set this environment variable to OOFFFF. By default, this environment variable is not set. NNOOTTEE:: The MMPPCC__GGAANNGG environment variable is outmoded. PPAAGGEESSIIZZEE__SSTTAACCKK, PPAAGGEESSIIZZEE__DDAATTAA, and PPAAGGEESSIIZZEE__TTEEXXTT Specifies the desired page size for each of the stack, data, and text segments. The default page size is 16 Kbytes on IRIX 6.4 and later systems; the default is 4 Kbytes on systems running previous IRIX revisions. These environment variables accept an integer value that represents the desired size in Kbytes. Typical values for this environment variable are 4, 16, or 64. Your operating system may not be able to accommodate larger values. If unsuitable values are specified, the system may adjust your page size to be lower than requested. II//OO EENNVVIIRROONNMMEENNTT VVAARRIIAABBLLEESS The following environment variables are used by the I/O libraries. FFFF__IIOO__AAIIOO__LLOOCCKKSS, FFFF__IIOO__AAIIOO__NNUUMMUUSSEERRSS, FFFF__IIOO__AAIIOO__TTHHRREEAADDSS Specifies aspects of the aaiiooiinniitt structure. This structure contains the following fields: aaiioo__lloocckkss, aaiioo__nnuummuusseerrss, and aaiioo__tthhrreeaaddss. These three environment variables alter the values used for these fields. For more information on using these environment variables, see the _A_p_p_l_i_c_a_t_i_o_n _P_r_o_g_r_a_m_m_e_r'_s _I/_O _G_u_i_d_e, publication SG-2168, and the AAIIOO__SSGGII__IINNIITT(3) man page. FFFF__IIOO__LLOOGGFFIILLEE Names a file to which statistics are written by the eevveenntt FFIO layer. FFIILLEENNVV Specifies the location of the aassssiiggnn environment information. Use FFIILLEENNVV to assign a file name to store the aassssiiggnn information or to specify that it be stored in the process environment. MMIISSCCEELLLLAANNEEOOUUSS EENNVVIIRROONNMMEENNTT VVAARRIIAABBLLEESS The following miscellaneous environment variables also affect compiling. CCOOMMPPIILLEERR__DDEEFFAAUULLTTSS__PPAATTHH Specifies the a path or a colon-separated lists of paths designating where the compiler is to look for the ccoommppiilleerr..ddeeffaauullttss file. The ccoommppiilleerr..ddeeffaauullttss file contains the following line: --DDEEFFAAUULLTT [::aabbii==_a_b_i] [::iissaa==_m_i_p_s__n_u_m] [::pprroocc==_p_r_o_c__n_u_m] [::oopptt==_o_p_t__l_v_l] [::aarriitthh==_a_r_i_t_h__l_v_l] The information in this file is used when compiling code unless it is overridden by command line options. The following list indicates the values to be specified on the --DDEEFFAAUULLTT line and the command line options that supercede the --DDEEFFAAUULLTT line specification: _a_b_i Specifies the Application Binary Interface (ABI). The --nn3322 and --6644 options to the ff9900(1) command override this specification. Specify either nn3322 or 6644 for _a_b_i. _m_i_p_s__n_u_m Specifies the Instruction Set Architecture (ISA). The --mmiippss44 and --mmiippss44 options to the ff9900(1) command override this specification. Specify either mmiippss33 or mmiippss44 for _m_i_p_s__n_u_m. _p_r_o_c__n_u_m Specifies the processor number. The --rr44kk, --rr55kk, --rr88kk, and --rr1100kk options to the ff9900(1) command override this specification. Specify one of the following for _p_r_o_c__n_u_m: rr44kk, rr55kk, rr88kk, rr1100kk. _o_p_t__l_v_l Specifies the general optimization level used when compiling. The --OO00, --OO11, --OO22, and --OO33 options to the ff9900(1) command override this specification. Specify one of the following for _o_p_t__l_v_l: 00, 11, 22, 33. _a_r_i_t_h__l_v_l Specifies the IEEE arithmetic level used when compiling. The --OOPPTT::IIEEEEEE__aarriitthh option to the ff9900(1) command overrides this specification. Specify one of the following for _a_r_i_t_h__l_v_l: 11, 22, 33. If no file is present, or if this environment variable is not set, the compiler looks in the default directory, which is //eettcc. For example, the following command line: %f90 -64 myfile.f overrides a ccoommppiilleerr..ddeeffaauullttss file that contains: -DEFAULT:abi=n32:isa=mips4:proc=r10k and performs a --6644,, --mmiippss44, --rr1100000000 compilation. FF22CCFFLLAAGGSS Controls the Fortran-to-C interface. As a value for this environment variable, specify options to the mmkkff22cc(1) command. For example, if you want to pass the --ll and the --ssiiggnneedd command line options to mmkkff22cc(1), and you are using the C shell, you can specify the following in your ..ccsshhrrcc file: sseetteennvv FF22CCFFLLAAGGSS --ssiiggnneedd --ll. FF9900__BBOOUUNNDDSS__CCHHEECCKK__AABBOORRTT Controls whether the compiler aborts compilation if a bounds check fails. The --CC option on the ff9900(1) command performs array bounds checking. By default, the compilation continues even if the bounds check fails. To cause the compiler to abort on a failed bounds check, set the FF9900__BBOOUUNNDDSS__CCHHEECCKK__AABBOORRTT environment variable to YYEESS. NNLLSSPPAATTHH Affects compiler interactions with the message system. For more information, see ccaattooppeenn(3C). SSGGII__AABBII Specifies the Application Binary Interface (ABI) used during compilation. This environment variable can be used to change the default ABI. Specify --nn3322 or --6644 as values. See GGEETTAABBII(3C) for more information. TTMMPPDDIIRR Specifies a path for temporary files. When set, the value used is the directory in which the system places temporary files, rather than the default, //ttmmpp. TTRRAAPP__FFPPEE Controls the handling and classifying of floating-point exceptions and substitutes new values. It also provides a mechanism to count, trace, exit, or abort on enabled exceptions. The --TTEENNVV::cchheecckk__ddiivv option on the ff9900(1) command line option inserts checks for divide by zero and for overflow. See FFSSIIGGFFPPEE(3F) for information on HHAANNDDLLEE__FFSSIIGGFFPPEESS, which performs a function similar to that of this environment variable. For more information on this environment variable, including its possible values, see FFSSIIGGFFPPEE(3F). __XXPPGG Specifies that compilation should proceed according to X/Open XPG4 specifications. If set, ff7777 (or ffoorrtt7777, as it is known under XPG4) operates in conformance with the X/Open XPG4 specifications. The options and the command line behavior may differ in accordance to the XPG4 standards. CCAAUUTTIIOONNSS The following two environment variables should not be changed from their system-supplied default settings: CCOOMMPP__TTAARRGGEETT__RROOOOTT and TTOOOOLLRROOOOTT. By default, the CCOOMMPP__TTAARRGGEETT__RROOOOTT environment variable is set to /. SSEEEE AALLSSOO aassssiiggnn(1), ff9900(1), mmkkff22cc(1). ccaattooppeenn(3C), FFSSIIGGFFPPEE(3F), GGEETTAABBII(3C), MMPP(3F). _A_p_p_l_i_c_a_t_i_o_n _P_r_o_g_r_a_m_m_e_r'_s _I/_O _G_u_i_d_e, publication SG-2168 _M_I_P_S_P_r_o _7 _F_o_r_t_r_a_n _9_0 _C_o_m_m_a_n_d_s _a_n_d _D_i_r_e_c_t_i_v_e_s _R_e_f_e_r_e_n_c_e _M_a_n_u_a_l, publication SR-3907 This man page is available only online.