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Created by Unknown User (nagc), last modified on Nov 16, 2016
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OpenIFS includes a compilation configuration for the Intel compiler with the Intel MKL library (for optimized LAPACK/BLAS). However, please be aware use of this library can cause the model to be irreproducible, even on the same core count in successive runs. We recommend not using it if reproducibility is a concern.
OpenIFS also only provides a compilation configuration for the MKL and the Intel library. Linking MKL with other compilers is possible, though complicated and is not tried or tested with OpenIFS.
For help with linking the MKL library with other compilers, please see: https://software.intel.com/en-us/articles/intel-mkl-link-line-advisor
There is an issue with OpenIFS when compiling with the Intel compiler at optimization level -O2 or above on chipsets that support SSE4.1 & AVX instructions. Intel compilers are generally more aggressive at optimisations for -O2 than other compilers.
Users will see failure with the T21 test job similar to the following:
signal_harakiri(SIGALRM=14): New handler installed at 0x432110; old preserved at 0x0
***Received signal = 8 and ActivatED SIGALRM=14 and calling alarm(10), time = 6.18
myproc#1,tid#1,pid#27600,signal#8(SIGFPE): Received signal :: 123MB (heap), 125MB (rss), 0MB (stack), 0 (paging), nsigs 1, time 6.18
tid#1 starting drhook traceback, time = 6.18
myproc#1,tid#1,pid#27600: MASTER
myproc#1,tid#1,pid#27600: CNT0<1>
myproc#1,tid#1,pid#27600: CNT1
myproc#1,tid#1,pid#27600: CNT2
myproc#1,tid#1,pid#27600: CNT3
myproc#1,tid#1,pid#27600: CNT4
myproc#1,tid#1,pid#27600: STEPO
myproc#1,tid#1,pid#27600: SCAN2H
myproc#1,tid#1,pid#27600: SCAN2M
myproc#1,tid#1,pid#27600: GP_MODEL
myproc#1,tid#1,pid#27600: EC_PHYS_DRV
myproc#1,tid#1,pid#27600: >OMP-PHYSICS CLDPP T/S (1002)
myproc#1,tid#1,pid#27600: EC_PHYS
myproc#1,tid#1,pid#27600: CALLPAR
myproc#1,tid#1,pid#27600: SLTEND
It arises because this compiler makes use of 2-way vectorization when compiling both branches of IF statements which can generate floating point exceptions if a zero divide is possible in the unexecuted branch and the IFS internal signal handler (DRHOOK) is enabled.
There are several possible workarounds:
- Compile the routines that cause the problem with lower optimisation, -O1. The routines affected are:
sltend.F90, vsurf_mod.F90, vdfmain.F90, vdfhghtn.F90. - Run with the environment variable: DR_HOOK_IGNORE_SIGNALS=8 to disable trapping of floating point exception signals (SIGFPE) by the model. This is not ideal as it will not catch other causes of floating point exceptions.
Edit the code and insert the line:
directly after the SUBROUTINE statement into the routines: sltend.F90, vsurf_mod.F90, vdfmain.F90, vdfhghtn.F90.
- Edit the intel-*.cfg configuration files in make/cfg and add lines to change the compile options specifically for these files.
OpenIFS uses a default of -O1 in the configuration files. If you increase the optimisation level, please be aware of this issue.
For more help with this issue, please contact openifs-support@ecmwf.int.
We are aware of a problem in grib_api when using the Intel compiler that seems to affect different versions of grib_api and causes the model to fail with a floating point exception (SIGFPE). This is known to happen in the routine PRESET_GRIB_TEMPLATE or in the GRIB_F_SET_REAL8_ARRAY in the grib_api library. The advice is to reduce the optimization level when compiling grib_api to -O1 rather than -O2 or try a more recent version of the Intel compiler.
The error message that typifies this problem is:
***Received signal = 8 and ActivatED SIGALRM=14 and calling alarm(10), time = 3.10
JSETSIG: sl->active = 0
signal_harakiri(SIGALRM=14): New handler installed at 0xabfa00; old preserved at 0x0
***Received signal = 8 and ActivatED SIGALRM=14 and calling alarm(10), time = 3.10
[myproc#1,tid#1,pid#14063]: MASTER
[myproc#1,tid#1,pid#14063]: CNT0<1>
[myproc#1,tid#1,pid#14063]: SU0YOMB
[myproc#1,tid#1,pid#14063]: SU_GRIB_API
[myproc#1,tid#1,pid#14063]: PRESET_GRIB_TEMPLATE
JSETSIG: sl->active = 0
signal_harakiri(SIGALRM=14): New handler installed at 0xabfa00; old preserved at 0x0
or a traceback like this:
[gdb__sigdump] : Received signal#8(SIGFPE), pid=-1
[LinuxTraceBack]: Backtrace(s) for program 'oifs38r1/make/intel_mkl-opt_conv/oifs/bin/master.exe' (pid=38451) :
(pid=38451): oifs38r1/src_conv/ifsaux/utilities/linuxtrbk.c:109 : master.exe() [0xc14a2d]
(pid=38451): oifs38r1/src_conv/ifsaux/support/drhook.c:884 : master.exe() [0xac8ddb]
(pid=38451): <Unknown> : libpthread.so.0(+0xf7e0) [0x7f59e215b7e0]
(pid=38451): <Unknown> : libgrib_api.so.0(log.L+0x23c) [0x7f59e60db98c]
(pid=38451): <Unknown> : libgrib_api.so.0(+0xa7de4) [0x7f59e60a7de4]
(pid=38451): <Unknown> : libgrib_api.so.0(+0x9c6d4) [0x7f59e609c6d4]
(pid=38451): <Unknown> : libgrib_api.so.0(grib_pack_double+0x18) [0x7f59e6079847]
(pid=38451): <Unknown> : libgrib_api.so.0(+0xc4814) [0x7f59e60c4814]
(pid=38451): <Unknown> : libgrib_api.so.0(+0xc4890) [0x7f59e60c4890]
(pid=38451): <Unknown> : libgrib_api.so.0(grib_set_double_array_internal+0x68) [0x7f59e60c4921]
(pid=38451): <Unknown> : libgrib_api.so.0(+0xa3a4a) [0x7f59e60a3a4a]
(pid=38451): <Unknown> : libgrib_api.so.0(grib_pack_double+0x18) [0x7f59e6079847]
(pid=38451): <Unknown> : libgrib_api.so.0(+0xc4814) [0x7f59e60c4814]
(pid=38451): <Unknown> : libgrib_api.so.0(+0xc4890) [0x7f59e60c4890]
(pid=38451): <Unknown> : libgrib_api.so.0(+0xc4b3f) [0x7f59e60c4b3f]
(pid=38451): <Unknown> : libgrib_api_f90.so.0(grib_f_set_real8_array_+0x51) [0x7f59e6380aea]
(pid=38451): <Unknown> : libgrib_api_f90.so.0(grib_api_mp_grib_set_real8_array_+0x8a) [0x7f59e63858af]
(pid=38451): oifs38r1/src_conv/ifsaux/module/grib_api_interface.F90:358 : master.exe() [0xb03bbd]
Note that the grib packing can also fail if the model has produced fields with a very large range of values, such that the grib library can't pack the values into a smaller bit range. For further help, please contact openifs-support@ecmwf.int.