diff --git a/tools/compare-grep-sort.sh b/tools/compare-grep-sort.sh
index 322ff606..804a5c72 100755
--- a/tools/compare-grep-sort.sh
+++ b/tools/compare-grep-sort.sh
@@ -21,6 +21,7 @@ cd "$(dirname "${0}")/.."
 if [[ -d '.git' ]]; then
     (set -x; git log -n1 --format='%h %D')
 fi
+PROGRAM_PASSED=${PROGRAM-}
 PROGRAM=${PROGRAM-./target/release/s4}
 (set -x; "${PROGRAM}" --version)
 # use full path to Unix tools
@@ -50,6 +51,8 @@ tmp2=$(mktemp -t "compare-s4_grep_XXXXX")
 tmp2b=$(mktemp -t "compare-s4-sorted_grep_XXXXX")
 md1=$(mktemp -t "compare-s4_s4_XXXXX.md")
 md2=$(mktemp -t "compare-s4_s4_XXXXX.md")
+md3=$(mktemp -t "compare-s4_s4_XXXXX.md")
+md4=$(mktemp -t "compare-s4_s4_XXXXX.md")
 mdfinal=${DIROUT-.}/compare-s4_grep_sort.md
 
 function exit_() {
@@ -122,12 +125,37 @@ declare -ar grep_args=(
 
 # run both programs using hyperfine
 
-if [[ -n "${hyperfine-}" ]]; then
+if [[ -n "${hyperfine-}" ]] && [[ -z "${PROGRAM_PASSED}" ]]; then
     (
+        (set -x; cargo clean --quiet; cargo build --release --quiet)
         # force reading of FILES from disk to allow any possible caching,
         cat "${FILES[@]}" &> /dev/null
         set -x
-        $hyperfine --style=basic --export-markdown ${md1} -N -n "s4" \
+        $hyperfine --style=basic --export-markdown ${md1} -N -n "s4 (System)" \
+            -- \
+            "${PROGRAM} ${s4_args[*]} ${FILES[*]}"
+    )
+
+    echo
+
+    (
+        (set -x; cargo clean --quiet; cargo build --release --quiet --features=mimalloc)
+        # force reading of FILES from disk to allow any possible caching,
+        cat "${FILES[@]}" &> /dev/null
+        set -x
+        $hyperfine --style=basic --export-markdown ${md2} -N -n "s4 (mimalloc)" \
+            -- \
+            "${PROGRAM} ${s4_args[*]} ${FILES[*]}"
+    )
+
+    echo
+
+    (
+        (set -x; cargo clean --quiet; cargo build --release --quiet --features=jemalloc)
+        # force reading of FILES from disk to allow any possible caching,
+        cat "${FILES[@]}" &> /dev/null
+        set -x
+        $hyperfine --style=basic --export-markdown ${md3} -N -n "s4 (jemalloc)" \
             -- \
             "${PROGRAM} ${s4_args[*]} ${FILES[*]}"
     )
@@ -140,7 +168,7 @@ if [[ -n "${hyperfine-}" ]]; then
         # force reading of FILES from disk to allow any possible caching,
         cat "${FILES[@]}" &> /dev/null
         set -x
-        $hyperfine --style=basic --export-markdown ${md2} --shell sh -n "${grep_sort_name}" \
+        $hyperfine --style=basic --export-markdown ${md4} --shell sh -n "${grep_sort_name}" \
             -- \
             "$grep -hEe '${regex_dt}' ${FILES[*]} | $sort -t ' ' -k 1 -s"
     )
@@ -148,6 +176,8 @@ if [[ -n "${hyperfine-}" ]]; then
     (
         cat "${md1}"
         cat "${md2}" | tail -n +3
+        cat "${md3}" | tail -n +3
+        cat "${md4}" | tail -n +3
     ) | column -t -s '|' -o '|' > "${mdfinal}"
 
     (set -x; cat "${mdfinal}")
@@ -162,6 +192,35 @@ fi
 TIME_FORMAT='real %e s, Max RSS %M KB, %P %%CPU, (%x)'
 
 (
+    (set -x; cargo clean --quiet; cargo build --release --quiet)
+    set -x
+    $time --format="${TIME_FORMAT}" \
+        "${@}" \
+        -- \
+        "${PROGRAM}" \
+        "${s4_args[@]}" \
+        "${FILES[@]}" \
+        >/dev/null
+)
+
+echo
+
+(
+    (set -x; cargo clean --quiet; cargo build --release --quiet --features=mimalloc)
+    set -x
+    $time --format="${TIME_FORMAT}" \
+        "${@}" \
+        -- \
+        "${PROGRAM}" \
+        "${s4_args[@]}" \
+        "${FILES[@]}" \
+        >/dev/null
+)
+
+echo
+
+(
+    (set -x; cargo clean --quiet; cargo build --release --quiet --features=jemalloc)
     set -x
     $time --format="${TIME_FORMAT}" \
         "${@}" \
diff --git a/tools/compare-log-mergers/compare-log-mergers.sh b/tools/compare-log-mergers/compare-log-mergers.sh
index 1f787937..4a0fdd02 100755
--- a/tools/compare-log-mergers/compare-log-mergers.sh
+++ b/tools/compare-log-mergers/compare-log-mergers.sh
@@ -70,10 +70,12 @@ tmp1=$(mktemp -t "compare-log-mergers_XXXXX.out")
 md1=$(mktemp -t "compare-log_mergers_XXXXX.md")
 md2=$(mktemp -t "compare-log_mergers_XXXXX.md")
 md3=$(mktemp -t "compare-log_mergers_XXXXX.md")
+md4=$(mktemp -t "compare-log_mergers_XXXXX.md")
+md5=$(mktemp -t "compare-log_mergers_XXXXX.md")
 mdfinal=${DIROUT-.}/compare-log_mergers.md
 
 function exit_() {
-    rm -f "${tmp1}" "${md1}" "${md2}" "${md3}"
+    rm -f "${tmp1}" "${md1}" "${md2}" "${md3}" "${md4}" "${md5}"
 }
 
 trap exit_ EXIT
@@ -136,7 +138,7 @@ echo
 cat "${md1}"
 echo
 
-# Super Speedy Syslog Searcher (S4)
+# Super Speedy Syslog Searcher (S4) (system)
 
 echo_line
 
@@ -146,9 +148,10 @@ PROGRAM_S4=${PROGRAM_S4-./target/release/s4}
 echo
 
 (
+    (set -x; cargo clean --quiet; cargo build --quiet --release)
     files_caching
     set -x
-    $hyperfine --style=basic --export-markdown "${md2}" -N -n "s4" \
+    $hyperfine --style=basic --export-markdown "${md2}" -N -n "s4 (system)" \
         -- \
         "'${PROGRAM_S4}' -a='${after_dt}' -b='${befor_dt}' --color=never ${files[*]} > /dev/null"
 )
@@ -170,6 +173,66 @@ echo
 cat "${md2}"
 echo
 
+# Super Speedy Syslog Searcher (S4) (mimalloc)
+
+echo_line
+
+(
+    (set -x; cargo clean --quiet; cargo build --quiet --release --features=mimalloc)
+    files_caching
+    set -x
+    $hyperfine --style=basic --export-markdown "${md3}" -N -n "s4 (mimalloc)" \
+        -- \
+        "'${PROGRAM_S4}' -a='${after_dt}' -b='${befor_dt}' --color=never ${files[*]} > /dev/null"
+)
+(
+    files_caching
+    set -x
+    $time --format="${TIME_FORMAT}" \
+        "${@}" \
+        -- \
+        "${PROGRAM_S4}" \
+        "-a=${after_dt}" \
+        "-b=${befor_dt}" \
+        "--color=never" \
+        "${files[@]}" > "${tmp1}"
+)
+echo
+wc -l "${tmp1}"
+echo
+cat "${md3}"
+echo
+
+# Super Speedy Syslog Searcher (S4) (jemalloc)
+
+echo_line
+
+(
+    (set -x; cargo clean --quiet; cargo build --quiet --release --features=jemalloc)
+    files_caching
+    set -x
+    $hyperfine --style=basic --export-markdown "${md4}" -N -n "s4 (jemalloc))" \
+        -- \
+        "'${PROGRAM_S4}' -a='${after_dt}' -b='${befor_dt}' --color=never ${files[*]} > /dev/null"
+)
+(
+    files_caching
+    set -x
+    $time --format="${TIME_FORMAT}" \
+        "${@}" \
+        -- \
+        "${PROGRAM_S4}" \
+        "-a=${after_dt}" \
+        "-b=${befor_dt}" \
+        "--color=never" \
+        "${files[@]}" > "${tmp1}"
+)
+echo
+wc -l "${tmp1}"
+echo
+cat "${md4}"
+echo
+
 # logmerger
 
 echo_line
@@ -186,7 +249,7 @@ echo
 (
     files_caching
     set -x
-    $hyperfine --style=basic --export-markdown "${md3}" --shell sh -n "${PROGRAM_LM}" \
+    $hyperfine --style=basic --export-markdown "${md5}" --shell sh -n "${PROGRAM_LM}" \
         -- \
         "'${PROGRAM_LM}' --inline --output=- --start '${after_dt}' --end '${befor_dt}' ${files[*]} > /dev/null"
 )
@@ -209,7 +272,7 @@ echo
 echo
 wc -l "${tmp1}"
 echo
-cat "${md3}"
+cat "${md5}"
 echo
 
 # logdissect
@@ -270,6 +333,8 @@ echo
     cat "${md1}"
     cat "${md2}" | tail -n +3
     cat "${md3}" | tail -n +3
+    cat "${md4}" | tail -n +3
+    cat "${md5}" | tail -n +3
 ) | column -t -s '|' -o '|' > "${mdfinal}"
 
 (set -x; cat "${mdfinal}")