Replace racey process substitution with a simpler stderr/stdout swap

benchmark/benchmark.sh

@@ -14,21 +14,32 @@ for size in $(seq 3 8); do
     echo -e "\t Simple"
     g++ gemm_simple.cpp -DSIZE=$size -O3 -march=native
     for i in $(seq 1 ${REPEAT}); do
-        ${TIME} -f "%U, " ./a.out 2> >(tr -d '\n' | tee -a ${FILE}_simple.res) && echo
+        # GNU time produces its data on stderr, and we want to post-process it.
+        # But bash's pipe operator only works on stdout. So we need to swap
+        # stdout and stderr first.
+        /usr/bin/time -f "%U, " ./a.out 3>&1 1>&2 2>&3 3>&-                    \
+                    | tr -d '\n' | tee -a ${FILE}_simple.res                   \
+        && echo
     done
     echo >> ${FILE}_simple.res
 
     echo -e "\t Eigen"
     g++ gemm_eigen.cpp -DSIZE=$size -O3 -march=native
     for i in $(seq 1 ${REPEAT}); do
-        ${TIME} -f "%U, " ./a.out 2> >(tr -d '\n' | tee -a ${FILE}_eigen.res) && echo
+        # Same as above, only targeting a different file
+        /usr/bin/time -f "%U, " ./a.out 3>&1 1>&2 2>&3 3>&-                    \
+                    | tr -d '\n' | tee -a ${FILE}_eigen.res                    \
+        && echo
     done
     echo >> ${FILE}_eigen.res
 
     echo -e "\t Custom"
     g++ gemm_custom.cpp -DSIZE=$size -O3 -march=native
     for i in $(seq 1 ${REPEAT}); do
-        ${TIME} -f "%U, " ./a.out 2> >(tr -d '\n' | tee -a ${FILE}_custom.res) && echo
+        # Same as above, only targeting a different file
+        /usr/bin/time -f "%U, " ./a.out 3>&1 1>&2 2>&3 3>&-                    \
+                    | tr -d '\n' | tee -a ${FILE}_custom.res                   \
+        && echo
     done
     echo >> ${FILE}_custom.res
 

measure_perf.sh

@@ -10,13 +10,21 @@ rm -f eigen_${FILE}
 for size in $(seq 3 8); do
     g++ matrix_product_custom.cpp -DSIZE=$size -O3 -march=native
     for i in $(seq 1 ${REPEAT}); do
-        /usr/bin/time -f "%U, " ./a.out 2> >(tr -d '\n' | tee -a custom_${FILE}) && echo
+        # GNU time produces its data on stderr, and we want to post-process it.
+        # But bash's pipe operator only works on stdout. So we need to swap
+        # stdout and stderr first.
+        /usr/bin/time -f "%U, " ./a.out 3>&1 1>&2 2>&3 3>&-                    \
+                    | tr -d '\n' | tee -a custom_${FILE}                       \
+        && echo
     done
     echo >> custom_${FILE}
 
     g++ matrix_product_eigen.cpp -DSIZE=$size -O3 -march=native
     for i in $(seq 1 ${REPEAT}); do
-        /usr/bin/time -f "%U, " ./a.out 2> >(tr -d '\n' | tee -a eigen_${FILE}) && echo
+        # Same as above, only targeting a different file
+        /usr/bin/time -f "%U, " ./a.out 3>&1 1>&2 2>&3 3>&-                    \
+                    | tr -d '\n' | tee -a eigen_${FILE}                        \
+        && echo
     done
     echo >> eigen_${FILE}
 done