https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91030
Bug ID: 91030
Summary: Poor performance of I/O -fconvert=big-endian
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libfortran
Assignee: unassigned at gcc dot gnu.org
Reporter: dje at gcc dot gnu.org
CC: jvdelisle at gcc dot gnu.org, kargl at gcc dot gnu.org,
toon at gcc dot gnu.org
Target Milestone: ---
Created attachment 46533
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46533&action=edit
Testcase demonstrating poor performance of libgfortran -fconvert=big-endian
The performance of GFortran -fconvert=big-endian is horribly inefficient. This
prevents the use of GFortran for some HPC applications.
$ gcc -c -g -O2 walltime.c
$ gfortran -g -O2 -fconvert=big-endian wr.f90 walltime.o -o wr
$ ./wr
write time(sec) = 5.25
$ rm out.dat
$ gfortran -g -O2 wr.f90 walltime.o -o wr
$ ./wr
write time(sec) = 0.43
$ rm out.dat
