diff --git a/Makefile b/Makefile
index 9efbbb2..805302d 100644
--- a/Makefile
+++ b/Makefile
@@ -6,12 +6,12 @@ SHARED_LIB = libsparsemap.so
 #CFLAGS = -Wall -Wextra -Wpedantic -Of -std=c11 -Iinclude/ -fPIC
 #CFLAGS = -Wall -Wextra -Wpedantic -Og -g -std=c11 -Iinclude/ -fPIC
 #CFLAGS = -DSPARSEMAP_DIAGNOSTIC -DDEBUG -Wall -Wextra -Wpedantic -O0 -g -std=c11 -Iinclude/ -fPIC
-CFLAGS = -Wall -Wextra -Wpedantic -Og -g -std=c11 -Iinclude/ -fPIC
+CFLAGS = -Wall -Wextra -Wpedantic -Ofast -g -std=c11 -Iinclude/ -fPIC
 #CFLAGS = -DSPARSEMAP_DIAGNOSTIC -DDEBUG -Wall -Wextra -Wpedantic -Og -g -fsanitize=address,leak,object-size,pointer-compare,pointer-subtract,null,return,bounds,pointer-overflow,undefined -fsanitize-address-use-after-scope -std=c11 -Iinclude/ -fPIC
 #CFLAGS = -Wall -Wextra -Wpedantic -Og -g -fsanitize=all -fhardened -std=c11 -Iinclude/ -fPIC
 
 #TEST_FLAGS = -DDEBUG -Wall -Wextra -Wpedantic -O0 -g -std=c11 -Iinclude/ -Itests/ -fPIC
-TEST_FLAGS = -Wall -Wextra -Wpedantic -Og -g -std=c11 -Iinclude/ -Itests/ -fPIC
+TEST_FLAGS = -Wall -Wextra -Wpedantic -Ofast -g -std=c11 -Iinclude/ -Itests/ -fPIC
 #TEST_FLAGS = -DDEBUG -Wall -Wextra -Wpedantic -Og -g -fsanitize=address,leak,object-size,pointer-compare,pointer-subtract,null,return,bounds,pointer-overflow,undefined -fsanitize-address-use-after-scope -std=c11 -Iinclude/ -fPIC
 
 TESTS = tests/test
diff --git a/examples/soak.c b/examples/soak.c
index 17ab474..0894fab 100644
--- a/examples/soak.c
+++ b/examples/soak.c
@@ -576,7 +576,7 @@ void
 stats_header()
 {
   printf(
-    "iterations,idl_cap,idl_used,idl_bytes,sm_cap,sm_used,idl_loc_p50,idl_loc_p75,idl_loc_p90,idl_loc_p99,idl_loc_p999,sm_loc_p50,sm_loc_p75,sm_loc_p90,sm_loc_p99,sm_loc_p999,idl_take_p50,idl_take_p75,idl_take_p90,idl_take_p99,idl_take_p999,sm_take_p50,sm_take_p75,sm_take_p90,sm_take_p99,sm_take_p999\n");
+    "timestamp,iterations,idl_cap,idl_used,idl_bytes,sm_cap,sm_used,idl_loc_p50,idl_loc_p75,idl_loc_p90,idl_loc_p99,idl_loc_p999,sm_loc_p50,sm_loc_p75,sm_loc_p90,sm_loc_p99,sm_loc_p999,idl_take_p50,idl_take_p75,idl_take_p90,idl_take_p99,idl_take_p999,sm_take_p50,sm_take_p75,sm_take_p90,sm_take_p99,sm_take_p999\n");
 }
 
 void