diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
index 99db56c..2a4b8e1 100644
--- a/hw/ppc/ppc.c
+++ b/hw/ppc/ppc.c
@@ -51,8 +51,6 @@
 #  define LOG_TB(...) do { } while (0)
 #endif
 
-#define NSEC_PER_SEC    1000000000LL
-
 static void cpu_ppc_tb_stop (CPUPPCState *env);
 static void cpu_ppc_tb_start (CPUPPCState *env);
 
diff --git a/hw/ppc/spapr_rtc.c b/hw/ppc/spapr_rtc.c
index 83eb7c1..9da3746 100644
--- a/hw/ppc/spapr_rtc.c
+++ b/hw/ppc/spapr_rtc.c
@@ -26,6 +26,7 @@
  *
  */
 #include "cpu.h"
+#include "qemu/timer.h"
 #include "sysemu/sysemu.h"
 #include "hw/ppc/spapr.h"
 #include "qapi-event.h"
@@ -40,8 +41,6 @@
     int64_t ns_offset;
 };
 
-#define NSEC_PER_SEC    1000000000LL
-
 void spapr_rtc_read(DeviceState *dev, struct tm *tm, uint32_t *ns)
 {
     sPAPRRTCState *rtc = SPAPR_RTC(dev);
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index 2e3ffc8..954c34d 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -48,7 +48,6 @@
 # define DPRINTF_C(format, ...)      do { } while (0)
 #endif
 
-#define NSEC_PER_SEC    1000000000LL
 #define SEC_PER_MIN     60
 #define MIN_PER_HOUR    60
 #define SEC_PER_HOUR    3600
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index d4d7547..d7cd40b 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -32,7 +32,7 @@
 #include "trace.h"
 
 #define FRAME_TIMER_FREQ 1000
-#define FRAME_TIMER_NS   (1000000000 / FRAME_TIMER_FREQ)
+#define FRAME_TIMER_NS   (NSEC_PER_SEC / FRAME_TIMER_FREQ)
 #define UFRAME_TIMER_NS  (FRAME_TIMER_NS / 8)
 
 #define NB_MAXINTRATE    8        // Max rate at which controller issues ints
diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index 5923d60..4dda20b 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -5,7 +5,7 @@
 #include "qemu-common.h"
 #include "qemu/notify.h"
 
-#define NANOSECONDS_PER_SECOND 1000000000LL
+#define NSEC_PER_SEC 1000000000LL
 
 /* timers */
 
diff --git a/tests/rtl8139-test.c b/tests/rtl8139-test.c
index 4e0bf02..3bff0e3 100644
--- a/tests/rtl8139-test.c
+++ b/tests/rtl8139-test.c
@@ -12,6 +12,7 @@
 #include "libqtest.h"
 #include "libqos/pci-pc.h"
 #include "qemu/osdep.h"
+#include "qemu/timer.h"
 #include "qemu-common.h"
 
 /* Tests only initialization so far. TODO: Replace with functional tests */
@@ -20,7 +21,6 @@
 }
 
 #define CLK 33000000
-#define NS_PER_SEC 1000000000ULL
 
 static QPCIBus *pcibus;
 static QPCIDevice *dev;
@@ -86,7 +86,7 @@
         fatal("time too big %u\n", curr);
     }
     for (cnt = 0; ; ) {
-        clock_step(1 * NS_PER_SEC);
+        clock_step(1 * NSEC_PER_SEC);
         prev = curr;
         curr = in_Timer();
 
@@ -125,7 +125,7 @@
     out_IntrStatus(0x4000);
     curr = in_Timer();
     out_TimerInt(curr + 0.5 * CLK);
-    clock_step(1 * NS_PER_SEC);
+    clock_step(1 * NSEC_PER_SEC);
     out_Timer(0);
     if ((in_IntrStatus() & 0x4000) == 0) {
         fatal("we should have an interrupt here!\n");
@@ -137,7 +137,7 @@
     out_IntrStatus(0x4000);
     curr = in_Timer();
     out_TimerInt(curr + 0.5 * CLK);
-    clock_step(1 * NS_PER_SEC);
+    clock_step(1 * NSEC_PER_SEC);
     out_TimerInt(0);
     if ((in_IntrStatus() & 0x4000) == 0) {
         fatal("we should have an interrupt here!\n");
@@ -148,7 +148,7 @@
     next = curr + 5.0 * CLK;
     out_TimerInt(next);
     for (cnt = 0; ; ) {
-        clock_step(1 * NS_PER_SEC);
+        clock_step(1 * NSEC_PER_SEC);
         prev = curr;
         curr = in_Timer();
         diff = (curr-prev) & 0xffffffffu;
diff --git a/tests/test-throttle.c b/tests/test-throttle.c
index 0168445..33b6b95 100644
--- a/tests/test-throttle.c
+++ b/tests/test-throttle.c
@@ -40,19 +40,19 @@
     bkt.level = 1.5;
 
     /* leak an op work of time */
-    throttle_leak_bucket(&bkt, NANOSECONDS_PER_SECOND / 150);
+    throttle_leak_bucket(&bkt, NSEC_PER_SEC / 150);
     g_assert(bkt.avg == 150);
     g_assert(bkt.max == 15);
     g_assert(double_cmp(bkt.level, 0.5));
 
     /* leak again emptying the bucket */
-    throttle_leak_bucket(&bkt, NANOSECONDS_PER_SECOND / 150);
+    throttle_leak_bucket(&bkt, NSEC_PER_SEC / 150);
     g_assert(bkt.avg == 150);
     g_assert(bkt.max == 15);
     g_assert(double_cmp(bkt.level, 0));
 
     /* check that the bucket level won't go lower */
-    throttle_leak_bucket(&bkt, NANOSECONDS_PER_SECOND / 150);
+    throttle_leak_bucket(&bkt, NSEC_PER_SEC / 150);
     g_assert(bkt.avg == 150);
     g_assert(bkt.max == 15);
     g_assert(double_cmp(bkt.level, 0));
@@ -90,7 +90,7 @@
     bkt.level = 15.5;
     wait = throttle_compute_wait(&bkt);
     /* time required to do half an operation */
-    result = (int64_t)  NANOSECONDS_PER_SECOND / 150 / 2;
+    result = (int64_t)  NSEC_PER_SEC / 150 / 2;
     g_assert(wait == result);
 }
 
diff --git a/tests/wdt_ib700-test.c b/tests/wdt_ib700-test.c
index 513a533..10a5472 100644
--- a/tests/wdt_ib700-test.c
+++ b/tests/wdt_ib700-test.c
@@ -11,8 +11,7 @@
 #include <string.h>
 #include "libqtest.h"
 #include "qemu/osdep.h"
-
-#define NS_PER_SEC 1000000000ULL
+#include "qemu/timer.h"
 
 static void qmp_check_no_event(void)
 {
@@ -41,29 +40,29 @@
 
 static QDict *ib700_program_and_wait(QTestState *s)
 {
-    clock_step(NS_PER_SEC * 40);
+    clock_step(NSEC_PER_SEC * 40);
     qmp_check_no_event();
 
     /* 2 second limit */
     outb(0x443, 14);
 
     /* Ping */
-    clock_step(NS_PER_SEC);
+    clock_step(NSEC_PER_SEC);
     qmp_check_no_event();
     outb(0x443, 14);
 
     /* Disable */
-    clock_step(NS_PER_SEC);
+    clock_step(NSEC_PER_SEC);
     qmp_check_no_event();
     outb(0x441, 1);
-    clock_step(3 * NS_PER_SEC);
+    clock_step(3 * NSEC_PER_SEC);
     qmp_check_no_event();
 
     /* Enable and let it fire */
     outb(0x443, 13);
-    clock_step(3 * NS_PER_SEC);
+    clock_step(3 * NSEC_PER_SEC);
     qmp_check_no_event();
-    clock_step(2 * NS_PER_SEC);
+    clock_step(2 * NSEC_PER_SEC);
     return qmp_get_event("WATCHDOG");
 }
 
diff --git a/util/throttle.c b/util/throttle.c
index 706c131..ec70476 100644
--- a/util/throttle.c
+++ b/util/throttle.c
@@ -36,7 +36,7 @@
     double leak;
 
     /* compute how much to leak */
-    leak = (bkt->avg * (double) delta_ns) / NANOSECONDS_PER_SECOND;
+    leak = (bkt->avg * (double) delta_ns) / NSEC_PER_SEC;
 
     /* make the bucket leak */
     bkt->level = MAX(bkt->level - leak, 0);
@@ -72,7 +72,7 @@
  */
 static int64_t throttle_do_compute_wait(double limit, double extra)
 {
-    double wait = extra * NANOSECONDS_PER_SECOND;
+    double wait = extra * NSEC_PER_SEC;
     wait /= limit;
     return wait;
 }