[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCHv13 03/31] aio / timers: add qemu-timer.c utility fun
From: |
Alex Bligh |
Subject: |
[Qemu-devel] [PATCHv13 03/31] aio / timers: add qemu-timer.c utility functions |
Date: |
Wed, 21 Aug 2013 16:02:41 +0100 |
Add utility functions to qemu-timer.c for nanosecond timing.
Add qemu_clock_deadline_ns to calculate deadlines to
nanosecond accuracy.
Add utility function qemu_soonest_timeout to calculate soonest deadline.
Add qemu_timeout_ns_to_ms to convert a timeout in nanoseconds back to
milliseconds for when ppoll is not used.
Signed-off-by: Alex Bligh <address@hidden>
---
include/qemu/timer.h | 42 ++++++++++++++++++++++++++++++++++++++++++
qemu-timer.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 92 insertions(+)
diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index da43cbe..e0a51a1 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -40,6 +40,29 @@ int64_t qemu_get_clock_ns(QEMUClock *clock);
int64_t qemu_clock_has_timers(QEMUClock *clock);
int64_t qemu_clock_expired(QEMUClock *clock);
int64_t qemu_clock_deadline(QEMUClock *clock);
+
+/**
+ * qemu_clock_deadline_ns:
+ * @clock: the clock to operate on
+ *
+ * Calculate the timeout of the earliest expiring timer
+ * in nanoseconds, or -1 if no timer is set to expire.
+ *
+ * Returns: time until expiry in nanoseconds or -1
+ */
+int64_t qemu_clock_deadline_ns(QEMUClock *clock);
+
+/**
+ * qemu_timeout_ns_to_ms:
+ * @ns: nanosecond timeout value
+ *
+ * Convert a nanosecond timeout value (or -1) to
+ * a millisecond value (or -1), always rounding up.
+ *
+ * Returns: millisecond timeout value
+ */
+int qemu_timeout_ns_to_ms(int64_t ns);
+
void qemu_clock_enable(QEMUClock *clock, bool enabled);
void qemu_clock_warp(QEMUClock *clock);
@@ -67,6 +90,25 @@ int64_t cpu_get_ticks(void);
void cpu_enable_ticks(void);
void cpu_disable_ticks(void);
+/**
+ * qemu_soonest_timeout:
+ * @timeout1: first timeout in nanoseconds (or -1 for infinite)
+ * @timeout2: second timeout in nanoseconds (or -1 for infinite)
+ *
+ * Calculates the soonest of two timeout values. -1 means infinite, which
+ * is later than any other value.
+ *
+ * Returns: soonest timeout value in nanoseconds (or -1 for infinite)
+ */
+static inline int64_t qemu_soonest_timeout(int64_t timeout1, int64_t timeout2)
+{
+ /* we can abuse the fact that -1 (which means infinite) is a maximal
+ * value when cast to unsigned. As this is disgusting, it's kept in
+ * one inline function.
+ */
+ return ((uint64_t) timeout1 < (uint64_t) timeout2) ? timeout1 : timeout2;
+}
+
static inline QEMUTimer *qemu_new_timer_ns(QEMUClock *clock, QEMUTimerCB *cb,
void *opaque)
{
diff --git a/qemu-timer.c b/qemu-timer.c
index 4117add..df8f12b 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -273,6 +273,56 @@ int64_t qemu_clock_deadline(QEMUClock *clock)
return delta;
}
+/*
+ * As above, but return -1 for no deadline, and do not cap to 2^32
+ * as we know the result is always positive.
+ */
+
+int64_t qemu_clock_deadline_ns(QEMUClock *clock)
+{
+ int64_t delta;
+
+ if (!clock->enabled || !clock->active_timers) {
+ return -1;
+ }
+
+ delta = clock->active_timers->expire_time - qemu_get_clock_ns(clock);
+
+ if (delta <= 0) {
+ return 0;
+ }
+
+ return delta;
+}
+
+/* Transition function to convert a nanosecond timeout to ms
+ * This is used where a system does not support ppoll
+ */
+int qemu_timeout_ns_to_ms(int64_t ns)
+{
+ int64_t ms;
+ if (ns < 0) {
+ return -1;
+ }
+
+ if (!ns) {
+ return 0;
+ }
+
+ /* Always round up, because it's better to wait too long than to wait too
+ * little and effectively busy-wait
+ */
+ ms = (ns + SCALE_MS - 1) / SCALE_MS;
+
+ /* To avoid overflow problems, limit this to 2^31, i.e. approx 25 days */
+ if (ms > (int64_t) INT32_MAX) {
+ ms = INT32_MAX;
+ }
+
+ return (int) ms;
+}
+
+
QEMUTimer *qemu_new_timer(QEMUClock *clock, int scale,
QEMUTimerCB *cb, void *opaque)
{
--
1.7.9.5
- [Qemu-devel] [PATCHv13 12/31] aio / timers: Add a notify callback to QEMUTimerList, (continued)
- [Qemu-devel] [PATCHv13 12/31] aio / timers: Add a notify callback to QEMUTimerList, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 10/31] aio / timers: Add QEMUTimerListGroup and helper functions, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 22/31] aio / timers: Remove legacy qemu_clock_deadline & qemu_timerlist_deadline, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 09/31] aio / timers: Untangle include files, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 16/31] aio / timers: Convert mainloop to use timeout, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 23/31] aio / timers: Add qemu_clock_get_ms and qemu_clock_get_ms, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 19/31] aio / timers: Use all timerlists in icount warp calculations, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 17/31] aio / timers: On timer modification, qemu_notify or aio_notify, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 25/31] aio / timers: Remove main_loop_timerlist, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 18/31] aio / timers: Introduce new API timer_new and friends, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 03/31] aio / timers: add qemu-timer.c utility functions,
Alex Bligh <=
- [Qemu-devel] [PATCHv13 15/31] aio / timers: Convert aio_poll to use AioContext timers' deadline, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 20/31] aio / timers: Add documentation and new format calls, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 28/31] aio / timers: Add test harness for AioContext timers, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 21/31] aio / timers: Remove alarm timers, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 08/31] aio / timers: Split QEMUClock into QEMUClock and QEMUTimerList, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 29/31] aio / timers: Add scripts/switch-timer-api, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 27/31] aio / timers: convert block_job_sleep_ns and co_sleep_ns to new API, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 26/31] aio / timers: Convert rtc_clock to be a QEMUClockType, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 31/31] aio / timers: Remove legacy interface, Alex Bligh, 2013/08/21
- [Qemu-devel] [PATCHv13 24/31] aio / timers: Rearrange timer.h & make legacy functions call non-legacy, Alex Bligh, 2013/08/21