diff --git a/Makefile.inc b/Makefile.inc
index 62356af..10f3e8a 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -35,12 +35,12 @@ endif
 all: t b
 
 clean:
-	rm -f $(OBJS) t main.o main.h b bench.o tests.a
+	rm -f $(OBJS) t t.o main.h b b.o tests.a
 
 .c.o:
 	$(CC) $(CFLAGS) $(INC) -c -o $@ $<
 
-$(OBJS): $(ROOTDIR)/common/test.h
+$(OBJS): $(ROOTDIR)/common/test.h $(ROOTDIR)/Makefile.conf
 
 main.h: $(OBJS)
 	nm -f posix $+ |awk ' \
@@ -52,16 +52,16 @@ tests.a: $(OBJS)
 	$(AR) rc $@ $+
 	$(RANLIB) $@
 
-main.o: $(ROOTDIR)/common/main.c $(ROOTDIR)/common/test.h main.h
+t.o: $(ROOTDIR)/common/t.c $(ROOTDIR)/common/test.h main.h
 	$(CC) $(CFLAGS) $(INC) -I. -c -o $@ $<
 
-t: main.o tests.a
+t: t.o tests.a
 	$(CC) $+ $(LDFLAGS) -o $@
 
-bench.o: $(ROOTDIR)/common/bench.c $(ROOTDIR)/common/test.h main.h
+b.o: $(ROOTDIR)/common/b.c $(ROOTDIR)/common/test.h main.h
 	$(CC) $(CFLAGS) $(INC) -I. -c -o $@ $<
 
-b: bench.o tests.a
+b: b.o tests.a
 	$(CC) $+ $(LDFLAGS) -lrt -o $@
 
 .PHONY: all clean
diff --git a/common/b.c b/common/b.c
new file mode 100644
index 0000000..b82531c
--- /dev/null
+++ b/common/b.c
@@ -0,0 +1,136 @@
+#define _POSIX_C_SOURCE 200809L
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "test.h"
+
+#define T(t)
+#define B(t) void t();
+#include "main.h"
+#undef B
+
+static int verbose = 1;
+
+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 dt;
+//static unsigned long long bytes;
+
+#define SEC  1000000000ULL
+#define MAXN  500000000
+
+static unsigned long long tic() {
+	struct timespec ts;
+
+	if (clock_gettime(CLOCK_MONOTONIC, &ts) < 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 = tic();
+}
+
+void stop_timer() {
+	if (start)
+		dt += tic() - start;
+	start = 0;
+}
+
+void reset_timer() {
+	if (start)
+		start = tic();
+	dt = 0;
+}
+
+static int nextN() {
+	unsigned long long n = dt/N;
+
+	if (n)
+		n = SEC/2/n;
+	else
+		n = SEC/2;
+	n += n/2;
+	if (n > N*100ULL)
+		n = N*100ULL;
+	else if (n <= N)
+		n = N+1;
+	if (n > MAXN)
+		n = MAXN;
+	return n;
+}
+
+void vmstats() {
+	FILE *f;
+	char buf[256];
+	int maj, min, in_heap=0;
+	unsigned long l;
+	size_t vm_size=0, vm_rss=0, vm_priv_dirty=0;
+
+	f = fopen("/proc/self/smaps", "rb");
+	if (f) while (fgets(buf, sizeof buf, f)) {
+		if (sscanf(buf, "%*lx-%*lx %*s %*lx %x:%x %*lu %*s", &maj, &min)==2)
+			in_heap = (!maj && !min && !strstr(buf, "---p") && (strstr(buf, "[heap]") || !strchr(buf, '[')));
+		if (in_heap) {
+			if (sscanf(buf, "Size: %lu", &l)==1) vm_size += l;
+			else if (sscanf(buf, "Rss: %lu", &l)==1) vm_rss += l;
+			else if (sscanf(buf, "Private_Dirty: %lu", &l)==1) vm_priv_dirty += l;
+		}
+	}
+	if (f) fclose(f);
+	fprintf(stderr, " %7zu virt %7zu res %7zu dirty", vm_size, vm_rss, vm_priv_dirty);
+}
+
+void stats() {
+	if (dt/N > 100)
+		fprintf(stderr, "%10d N %10llu ns/op   ", N, dt/N);
+	else
+		fprintf(stderr, "%10d N %13.2f ns/op", N, (double)dt/N);
+	if (verbose)
+		vmstats();
+	fputc('\n', stderr);
+}
+
+static void run(const char *name, void (*f)()) {
+	int p = fork();
+	if (p) {
+		int s;
+		if (p<0 || wait(&s)<0 || !WIFEXITED(s) || WEXITSTATUS(s))
+			fprintf(stderr, "benchmark %s failed\n", name);
+		return;
+	}
+	fprintf(stderr, "%-32s", name);
+	for (N=1; ; N=nextN()) {
+		reset_timer();
+		start_timer();
+		f();
+		stop_timer();
+//		fprintf(stderr, "%10d%12llu next: %d\n", N, dt, nextN());
+		if (dt >= SEC/2 || N >= MAXN) {
+			stats();
+			exit(0);
+		}
+		if (N <= 0) {
+			fprintf(stderr, "bench: fatal: N <= 0\n");
+			exit(1);
+		}
+	}
+}
+
+int main() {
+#define B(t) run(#t, t);
+#include "main.h"
+	return 0;
+}
diff --git a/common/bench.c b/common/bench.c
deleted file mode 100644
index ee6daa1..0000000
--- a/common/bench.c
+++ /dev/null
@@ -1,97 +0,0 @@
-#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 dt;
-//static unsigned long long bytes;
-
-#define SEC  1000000000ULL
-#define MAXN 1000000000
-
-static unsigned long long tic() {
-	struct timespec ts;
-
-	if (clock_gettime(CLOCK_MONOTONIC, &ts) < 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 = tic();
-}
-
-void stop_timer() {
-	if (start)
-		dt += tic() - start;
-	start = 0;
-}
-
-void reset_timer() {
-	if (start)
-		start = tic();
-	dt = 0;
-}
-
-static int nextN() {
-	unsigned long long n = dt/N;
-
-	if (n)
-		n = SEC/n;
-	else
-		n = SEC;
-	n += n/4;
-	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 (dt >= SEC || N >= MAXN)
-			break;
-		if (N <= 0) {
-			fprintf(stderr, "bench: fatal: N <= 0\n");
-			return;
-		}
-	}
-	if (dt/N > 100)
-		fprintf(stderr, "%10d%10llu ns/op\n", N, dt/N);
-	else
-		fprintf(stderr, "%10d%13.2f ns/op\n", N, (double)dt/N);
-}
-
-int main() {
-#define B(t) run(#t, t);
-#include "main.h"
-	return 0;
-}
diff --git a/common/main.c b/common/main.c
deleted file mode 100644
index 02d77c7..0000000
--- a/common/main.c
+++ /dev/null
@@ -1,84 +0,0 @@
-#define _POSIX_C_SOURCE 200809L
-#include <stdlib.h>
-#include <stdio.h>
-#include <stdarg.h>
-#include <string.h>
-#include <errno.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
-
-static int failed;
-static const char *name;
-
-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;
-
-	failed = 1;
-	fprintf(stderr, "- ERROR %s at %s:%d: ", name, n, l);
-	va_start(ap, s);
-	vfprintf(stderr, s, ap);
-	va_end(ap);
-}
-
-static void run(const char *n, void (*f)()) {
-	pid_t pid;
-	int s;
-
-	count++;
-	failed = 0;
-	name = n;
-	if (verbose)
-		fprintf(stderr, "running %s:\n", name);
-
-	pid = fork();
-	if (pid == 0) {
-		/* run test in a child process */
-		f();
-		exit(failed);
-	}
-
-	if (pid == -1)
-		error("fork failed: %s\n", strerror(errno));
-	else {
-		if (waitpid(pid, &s, 0) == -1)
-			error("waitpid failed: %s\n", strerror(errno));
-		else if (!WIFEXITED(s))
-			error("abnormal exit: %s\n", WIFSIGNALED(s) ? strsignal(WTERMSIG(s)) : "(unknown)");
-		else
-			failed = !!WEXITSTATUS(s);
-	}
-
-	if (failed) {
-		nfailed++;
-		fprintf(stderr, "FAILED %s\n", name);
-	} else if (verbose)
-		fprintf(stderr, "PASSED %s\n", name);
-}
-
-static int summary() {
-	fprintf(stderr, "PASS:%d FAIL:%d\n", count-nfailed, nfailed);
-	return !!nfailed;
-}
-
-int main() {
-#define T(t) run(#t, t);
-#include "main.h"
-	return summary();
-}
diff --git a/common/t.c b/common/t.c
new file mode 100644
index 0000000..02d77c7
--- /dev/null
+++ b/common/t.c
@@ -0,0 +1,84 @@
+#define _POSIX_C_SOURCE 200809L
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <errno.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
+
+static int failed;
+static const char *name;
+
+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;
+
+	failed = 1;
+	fprintf(stderr, "- ERROR %s at %s:%d: ", name, n, l);
+	va_start(ap, s);
+	vfprintf(stderr, s, ap);
+	va_end(ap);
+}
+
+static void run(const char *n, void (*f)()) {
+	pid_t pid;
+	int s;
+
+	count++;
+	failed = 0;
+	name = n;
+	if (verbose)
+		fprintf(stderr, "running %s:\n", name);
+
+	pid = fork();
+	if (pid == 0) {
+		/* run test in a child process */
+		f();
+		exit(failed);
+	}
+
+	if (pid == -1)
+		error("fork failed: %s\n", strerror(errno));
+	else {
+		if (waitpid(pid, &s, 0) == -1)
+			error("waitpid failed: %s\n", strerror(errno));
+		else if (!WIFEXITED(s))
+			error("abnormal exit: %s\n", WIFSIGNALED(s) ? strsignal(WTERMSIG(s)) : "(unknown)");
+		else
+			failed = !!WEXITSTATUS(s);
+	}
+
+	if (failed) {
+		nfailed++;
+		fprintf(stderr, "FAILED %s\n", name);
+	} else if (verbose)
+		fprintf(stderr, "PASSED %s\n", name);
+}
+
+static int summary() {
+	fprintf(stderr, "PASS:%d FAIL:%d\n", count-nfailed, nfailed);
+	return !!nfailed;
+}
+
+int main() {
+#define T(t) run(#t, t);
+#include "main.h"
+	return summary();
+}