diff --git a/Makefile.inc b/Makefile.inc
index bfdc3dc..62356af 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -16,6 +16,8 @@ includedir = $(prefix)/include
 libdir = $(prefix)/lib
 -include $(ROOTDIR)/Makefile.conf
 
+AR=ar
+RANLIB=ranlib
 
 CFLAGS += -g -std=c99 -pipe -Wall
 LDFLAGS += -g
@@ -30,10 +32,10 @@ LDFLAGS += -nostdlib -Wl,-e,_start,-Bstatic $(libdir)/crti.o $(libdir)/crt1.o $(
 INC     += -isystem $(includedir)
 endif
 
-all: t
+all: t b
 
 clean:
-	rm -f $(OBJS) t main.o main.h
+	rm -f $(OBJS) t main.o main.h b bench.o tests.a
 
 .c.o:
 	$(CC) $(CFLAGS) $(INC) -c -o $@ $<
@@ -41,12 +43,25 @@ clean:
 $(OBJS): $(ROOTDIR)/common/test.h
 
 main.h: $(OBJS)
-	nm -f posix $+ |awk '/^test/ && $$2=="T"{print "T(" $$1 ")"}' >main.h
+	nm -f posix $+ |awk ' \
+		/^test/ && $$2=="T"{print "T(" $$1 ")"} \
+		/^bench/ && $$2=="T"{print "B(" $$1 ")"} \
+	' >main.h
+
+tests.a: $(OBJS)
+	$(AR) rc $@ $+
+	$(RANLIB) $@
 
 main.o: $(ROOTDIR)/common/main.c $(ROOTDIR)/common/test.h main.h
 	$(CC) $(CFLAGS) $(INC) -I. -c -o $@ $<
 
-t: $(OBJS) main.o
+t: main.o tests.a
 	$(CC) $+ $(LDFLAGS) -o $@
 
+bench.o: $(ROOTDIR)/common/bench.c $(ROOTDIR)/common/test.h main.h
+	$(CC) $(CFLAGS) $(INC) -I. -c -o $@ $<
+
+b: bench.o tests.a
+	$(CC) $+ $(LDFLAGS) -lrt -o $@
+
 .PHONY: all clean
diff --git a/common/bench.c b/common/bench.c
new file mode 100644
index 0000000..0436f67
--- /dev/null
+++ b/common/bench.c
@@ -0,0 +1,101 @@
+#define _POSIX_C_SOURCE 200809L
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+#include "test.h"
+
+#define T(t)
+#define B(t) void t();
+#include "main.h"
+#undef B
+
+//static int verbose;
+
+void error__(const char *n, int l, const char *s, ...) {
+	fprintf(stderr, "use error in tests only\n");
+}
+
+int N;
+static unsigned long long start;
+static unsigned long long ns;
+//static unsigned long long bytes;
+
+#define SEC  1000000000ULL
+#define MAXN 1000000000
+
+static unsigned long long nsclock() {
+	struct timespec ts;
+	int r;
+
+#ifdef _POSIX_CPUTIME
+	r = clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
+#else
+#ifdef _POSIX_MONOTONIC_CLOCK
+	r = clock_gettime(CLOCK_MONOTONIC, &ts);
+#else
+	r = clock_gettime(CLOCK_REALTIME, &ts);
+#endif
+#endif
+	if (r < 0) {
+		fprintf(stderr, "bench: clock_gettime failed: %s\n", strerror(errno));
+		return 0;
+	}
+	return ts.tv_sec*SEC + ts.tv_nsec;
+}
+
+void start_timer() {
+	if (!start)
+		start = nsclock();
+}
+
+void stop_timer() {
+	if (start)
+		ns += nsclock() - start;
+	start = 0;
+}
+
+void reset_timer() {
+	if (start)
+		start = nsclock();
+	ns = 0;
+}
+
+static int nextN() {
+	unsigned long long n = 2*SEC/(ns/N + 1);
+	if (n > N*100ULL)
+		n = N*100ULL;
+	else if (n <= N)
+		n = N+1;
+	if (n > MAXN)
+		n = MAXN;
+	return n;
+}
+
+static void run(const char *name, void (*f)()) {
+	fprintf(stderr, "%s:", name);
+	for (N=1; ; N=nextN()) {
+		reset_timer();
+		start_timer();
+		f();
+		stop_timer();
+//		fprintf(stderr, "%10d%12llu\n", N, ns);
+		if (ns > SEC || N >= MAXN)
+			break;
+		if (N <= 0) {
+			fprintf(stderr, "bench: fatal: N <= 0\n");
+			return;
+		}
+	}
+	if (ns/N > 100)
+		fprintf(stderr, "%10d%10llu ns/op\n", N, ns/N);
+	else
+		fprintf(stderr, "%10d%13.2f ns/op\n", N, (double)ns/N);
+}
+
+int main() {
+#define B(t) run(#t, t);
+#include "main.h"
+	return 0;
+}
diff --git a/common/main.c b/common/main.c
index 02e5f1f..02d77c7 100644
--- a/common/main.c
+++ b/common/main.c
@@ -4,12 +4,12 @@
 #include <stdarg.h>
 #include <string.h>
 #include <errno.h>
-#include <signal.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
 #include "test.h"
 
+#define B(t)
 #define T(t) void t();
 #include "main.h"
 #undef T
@@ -21,6 +21,12 @@ static int verbose;
 static int count;
 static int nfailed;
 
+static void errtimer() { error("use *_timer in benchmarks only\n"); }
+int N = 0;
+void start_timer() { errtimer(); }
+void stop_timer() { errtimer(); }
+void reset_timer() { errtimer(); }
+
 void error__(const char *n, int l, const char *s, ...) {
 	va_list ap;
 
diff --git a/common/test.h b/common/test.h
index b403c05..ed8adda 100644
--- a/common/test.h
+++ b/common/test.h
@@ -1,2 +1,9 @@
+/* use it in test_ functions */
 #define error(...) error__(__FILE__, __LINE__, __VA_ARGS__)
 void error__(const char *n, int l, const char *s, ...);
+
+/* use it in bench_ functions */
+extern int N;
+void start_timer(void);
+void stop_timer(void);
+void reset_timer(void);
diff --git a/src/foo/Makefile b/src/foo/Makefile
new file mode 100644
index 0000000..ee4552b
--- /dev/null
+++ b/src/foo/Makefile
@@ -0,0 +1 @@
+include ../../Makefile.inc
diff --git a/src/foo/foo.c b/src/foo/foo.c
new file mode 100644
index 0000000..637d7fa
--- /dev/null
+++ b/src/foo/foo.c
@@ -0,0 +1,28 @@
+#include "test.h"
+
+// dummy test
+
+static unsigned foo(unsigned n) {
+	int i;
+
+	for (i = 0; i < 10; i++) {
+		n = n*n;
+		n = n+123;
+		n = n/7;
+	}
+	return n;
+}
+
+void bench_foo() {
+	int i;
+
+	for (i = 0; i < N; i++)
+		foo(3);
+}
+
+void test_foo() {
+	unsigned n = foo(3);
+
+	if (n != 123)
+		error("foo(3):%u expected 123\n", n);
+}