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sudden very slow writing performance

lrego-developer
New Contributor I
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Hello,

I’ve encountered a sudden performance issue with the following piece of code. Previously, it took around 30 seconds to write a 500 MB file, but now it takes an unreasonably long time to complete the same task.

The code itself hasn’t been changed since it was working efficiently about a year ago. I suspect the issue might be related to recent changes in the compiler or its settings.

Has anyone experienced something similar or have insights into what might be causing this?

Thank you!

 

! Max. for ifort compiler
#define BLK_SIZE 67108864

. . . 

open(out, file='Occup_el.dat', status='unknown', buffered='yes', blocksize=BLK_SIZE)

do it = 1, n_t, it_step
do iE = indexEi(1), indexEf(1)
write(out,'(f11.6,i6,f11.6,2es13.3e3)') t(it), iE+iEmin-1, ergs(iE,1,it), occ(iE,1,it)
end do; write(out,*)
end do

close(out)

 

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lrego-developer
New Contributor I
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Sorry, I forgot to post the compiler configuration, for either ifort or ifx cases

##########################
# FORTRAN CONFIGURATIONS #
##########################
# Compiler
FC = ifort

# Applied to all fortran files
FC_ALL = -xHost -align -no-wrap-margin

# Parallelization flags
FC_PARALLEL = -qopenmp
f_FLAGS = -O2 -static-intel $(FC_PARALLEL)

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