Fixes are available
November 2012 PTF for XL C for AIX, V12.1
November 2012 PTF for XL C/C++ for AIX, V12.1
November 2012 PTF for XL Fortran for AIX, V14.1
November 2012 PTF for XL Fortran Runtime for AIX, V14.1
March 2013 PTF for XL C for AIX, V12.1
March 2013 PTF for XL C/C++ for AIX, V12.1
March 2013 PTF for XL Fortran for AIX, V14.1
March 2013 PTF for XL Fortran Runtime for AIX, V14.1
Closed as program error.
A runtime performance degradation is seen when using the XLSMPOPTS binding option as follows: =====Compile Line: xlf_r -O -q64 -qsmp=omp matmul.f -o matmul.exe =====Testcase: $ cat matmul.f program matmul1 implicit none real*8, allocatable, dimension(:,:,:) :: a,b,c integer, parameter :: n = 4000 integer i allocate(a(n,n,0:1),b(n,n,0:1),c(n,n,0:1)) a = 1.d0 b = 1.d0 !$OMP parallel do private(i) do i = 0,1 c(:,:,i) = matmul(a(:,:,i),b(:,:,i)) enddo deallocate(a,b,c) end $ ====Runtime output: #!/bin/ksh set -x export XLFRTEOPTS=intrinthds=1 export XLSMPOPTS=parthds=2 time ./matmul.exe export XLSMPOPTS=parthds=2:bindlist=proc=0,2 time ./matmul.exe The following are from a Power7 booted in SMT-2 mode (3.56GHz) $ ./run + export XLFRTEOPTS=intrinthds=1 + export XLSMPOPTS=parthds=2 + ./matmul.exe real 0m27.04s user 0m45.03s sys 0m0.00s + export XLSMPOPTS=parthds=2:bindlist=proc=0,2 + ./matmul.exe real 1m6.88s user 0m57.23s sys 0m0.00s
USERS AFFECTED: Users using the bind and bindlist options of XLSMPOPTS are potentially affected by this issue. PROBLEM DESCRIPTION: When using the bind or bindlist options of XLSMPOPTS, the compiler does not respect it and binds all threads to one CPU causing a performance degradation during runtime.
The issue was in the binding code within the compiler that binds threads to different CPUs. This has been fixed.
Reported component name
XL SMP AIX
Reported component ID
Last modified date
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fixed component name
XL SMP AIX
Fixed component ID
Applicable component levels
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