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[Qemu-devel] [PULL 01/33] mc146818rtc: update periodic timer only if it
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 01/33] mc146818rtc: update periodic timer only if it is needed |
Date: |
Thu, 1 Jun 2017 14:41:19 +0200 |
From: Xiao Guangrong <address@hidden>
Currently, the timer is updated whenever RegA or RegB is written
even if the periodic timer related configuration is not changed
This patch optimizes it slightly to make the update happen only
if its period or enable-status is changed, also later patches are
depend on this optimization
Signed-off-by: Xiao Guangrong <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/timer/mc146818rtc.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index 93de3e1..7d78391 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -391,6 +391,7 @@ static void cmos_ioport_write(void *opaque, hwaddr addr,
uint64_t data, unsigned size)
{
RTCState *s = opaque;
+ bool update_periodic_timer;
if ((addr & 1) == 0) {
s->cmos_index = data & 0x7f;
@@ -423,6 +424,8 @@ static void cmos_ioport_write(void *opaque, hwaddr addr,
}
break;
case RTC_REG_A:
+ update_periodic_timer = (s->cmos_data[RTC_REG_A] ^ data) & 0x0f;
+
if ((data & 0x60) == 0x60) {
if (rtc_running(s)) {
rtc_update_time(s);
@@ -445,10 +448,17 @@ static void cmos_ioport_write(void *opaque, hwaddr addr,
/* UIP bit is read only */
s->cmos_data[RTC_REG_A] = (data & ~REG_A_UIP) |
(s->cmos_data[RTC_REG_A] & REG_A_UIP);
- periodic_timer_update(s, qemu_clock_get_ns(rtc_clock));
+
+ if (update_periodic_timer) {
+ periodic_timer_update(s, qemu_clock_get_ns(rtc_clock));
+ }
+
check_update_timer(s);
break;
case RTC_REG_B:
+ update_periodic_timer = (s->cmos_data[RTC_REG_B] ^ data)
+ & REG_B_PIE;
+
if (data & REG_B_SET) {
/* update cmos to when the rtc was stopping */
if (rtc_running(s)) {
@@ -475,7 +485,11 @@ static void cmos_ioport_write(void *opaque, hwaddr addr,
qemu_irq_lower(s->irq);
}
s->cmos_data[RTC_REG_B] = data;
- periodic_timer_update(s, qemu_clock_get_ns(rtc_clock));
+
+ if (update_periodic_timer) {
+ periodic_timer_update(s, qemu_clock_get_ns(rtc_clock));
+ }
+
check_update_timer(s);
break;
case RTC_REG_C:
--
1.8.3.1
- [Qemu-devel] [PULL 00/33] Misc patches for 2017-06-01, Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 01/33] mc146818rtc: update periodic timer only if it is needed,
Paolo Bonzini <=
- [Qemu-devel] [PULL 04/33] mc146818rtc: drop unnecessary '#ifdef TARGET_I386', Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 07/33] msix: trace control bit write op, Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 03/33] mc146818rtc: ensure LOST_TICK_POLICY_SLEW is only enabled on TARGET_I386, Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 02/33] mc146818rtc: precisely count the clock for periodic timer, Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 08/33] kvm: irqchip: skip update msi when disabled, Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 09/33] Check the return value of fcntl in qemu_set_cloexec, Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 05/33] mc146818rtc: embrace all x86 specific code, Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 10/33] nbd: strict nbd_wr_syncv, Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 06/33] kvm: irqchip: trace changes on msi add/remove, Paolo Bonzini, 2017/06/01
- [Qemu-devel] [PULL 15/33] exec: simplify phys_page_find() params, Paolo Bonzini, 2017/06/01