hw/timer/mc146818rtc.c | 55 ++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 47 insertions(+), 8 deletions(-)
As windows guest use rtc as the clock source device,
and access rtc frequently. Let's move the rtc memory
region outside BQL to decrease overhead for windows guests.
Meanwhile, adding a new lock to avoid different vCPUs
access the RTC together.
I tested PCMark 8 (https://www.futuremark.com/benchmarks/pcmark)
in win7 guest and got the below results:
Guest: 2U2G
Before applying the patch:
Your Work 2.0 score: 2000
Web Browsing - JunglePin 0.334s
Web Browsing - Amazonia 0.132s
Writing 3.59s
Spreadsheet 70.13s
Video Chat v2/Video Chat playback 1 v2 22.8 fps
Video Chat v2/Video Chat encoding v2 307.0 ms
Benchmark duration 1h 35min 46s
After applying the patch:
Your Work 2.0 score: 2040
Web Browsing - JunglePin 0.345s
Web Browsing - Amazonia 0.132s
Writing 3.56s
Spreadsheet 67.83s
Video Chat v2/Video Chat playback 1 v2 28.7 fps
Video Chat v2/Video Chat encoding v2 324.7 ms
Benchmark duration 1h 32min 5s
Test results show that optimization is effective under
stressful situations.
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
v3->v2:
a) fix a typo, 's/rasie/raise/' [Peter]
b) change commit message [Peter]
v2->v1:
a)Adding a new lock to avoid different vCPUs
access the RTC together. [Paolo]
b)Taking the BQL before raising the outbound IRQ line. [Peter]
c)Don't hold BQL if it was holden. [Peter]
hw/timer/mc146818rtc.c | 55 ++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 47 insertions(+), 8 deletions(-)
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index 35a05a6..f0a2a62 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -85,6 +85,7 @@ typedef struct RTCState {
uint16_t irq_reinject_on_ack_count;
uint32_t irq_coalesced;
uint32_t period;
+ QemuMutex rtc_lock;
QEMUTimer *coalesced_timer;
Notifier clock_reset_notifier;
LostTickPolicy lost_tick_policy;
@@ -125,6 +126,36 @@ static void rtc_coalesced_timer_update(RTCState *s)
}
}
+static void rtc_raise_irq(RTCState *s)
+{
+ bool unlocked = !qemu_mutex_iothread_locked();
+
+ if (unlocked) {
+ qemu_mutex_lock_iothread();
+ }
+
+ qemu_irq_raise(s->irq);
+
+ if (unlocked) {
+ qemu_mutex_unlock_iothread();
+ }
+}
+
+static void rtc_lower_irq(RTCState *s)
+{
+ bool unlocked = !qemu_mutex_iothread_locked();
+
+ if (unlocked) {
+ qemu_mutex_lock_iothread();
+ }
+
+ qemu_irq_lower(s->irq);
+
+ if (unlocked) {
+ qemu_mutex_unlock_iothread();
+ }
+}
+
static QLIST_HEAD(, RTCState) rtc_devices =
QLIST_HEAD_INITIALIZER(rtc_devices);
@@ -141,7 +172,7 @@ void qmp_rtc_reset_reinjection(Error **errp)
static bool rtc_policy_slew_deliver_irq(RTCState *s)
{
apic_reset_irq_delivered();
- qemu_irq_raise(s->irq);
+ rtc_raise_irq(s);
return apic_get_irq_delivered();
}
@@ -277,8 +308,9 @@ static void rtc_periodic_timer(void *opaque)
DPRINTF_C("cmos: coalesced irqs increased to %d\n",
s->irq_coalesced);
}
- } else
- qemu_irq_raise(s->irq);
+ } else {
+ rtc_raise_irq(s);
+ }
}
}
@@ -459,7 +491,7 @@ static void rtc_update_timer(void *opaque)
s->cmos_data[RTC_REG_C] |= irqs;
if ((new_irqs & s->cmos_data[RTC_REG_B]) != 0) {
s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
- qemu_irq_raise(s->irq);
+ rtc_raise_irq(s);
}
check_update_timer(s);
}
@@ -471,6 +503,7 @@ static void cmos_ioport_write(void *opaque, hwaddr addr,
uint32_t old_period;
bool update_periodic_timer;
+ qemu_mutex_lock(&s->rtc_lock);
if ((addr & 1) == 0) {
s->cmos_index = data & 0x7f;
} else {
@@ -560,10 +593,10 @@ static void cmos_ioport_write(void *opaque, hwaddr addr,
* becomes enabled, raise an interrupt immediately. */
if (data & s->cmos_data[RTC_REG_C] & REG_C_MASK) {
s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
- qemu_irq_raise(s->irq);
+ rtc_raise_irq(s);
} else {
s->cmos_data[RTC_REG_C] &= ~REG_C_IRQF;
- qemu_irq_lower(s->irq);
+ rtc_lower_irq(s);
}
s->cmos_data[RTC_REG_B] = data;
@@ -583,6 +616,7 @@ static void cmos_ioport_write(void *opaque, hwaddr addr,
break;
}
}
+ qemu_mutex_unlock(&s->rtc_lock);
}
static inline int rtc_to_bcd(RTCState *s, int a)
@@ -710,6 +744,7 @@ static uint64_t cmos_ioport_read(void *opaque, hwaddr addr,
if ((addr & 1) == 0) {
return 0xff;
} else {
+ qemu_mutex_lock(&s->rtc_lock);
switch(s->cmos_index) {
case RTC_IBM_PS2_CENTURY_BYTE:
s->cmos_index = RTC_CENTURY;
@@ -737,7 +772,7 @@ static uint64_t cmos_ioport_read(void *opaque, hwaddr addr,
break;
case RTC_REG_C:
ret = s->cmos_data[s->cmos_index];
- qemu_irq_lower(s->irq);
+ rtc_lower_irq(s);
s->cmos_data[RTC_REG_C] = 0x00;
if (ret & (REG_C_UF | REG_C_AF)) {
check_update_timer(s);
@@ -762,6 +797,7 @@ static uint64_t cmos_ioport_read(void *opaque, hwaddr addr,
}
CMOS_DPRINTF("cmos: read index=0x%02x val=0x%02x\n",
s->cmos_index, ret);
+ qemu_mutex_unlock(&s->rtc_lock);
return ret;
}
}
@@ -909,7 +945,7 @@ static void rtc_reset(void *opaque)
s->cmos_data[RTC_REG_C] &= ~(REG_C_UF | REG_C_IRQF | REG_C_PF | REG_C_AF);
check_update_timer(s);
- qemu_irq_lower(s->irq);
+ rtc_lower_irq(s);
if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) {
s->irq_coalesced = 0;
@@ -960,6 +996,8 @@ static void rtc_realizefn(DeviceState *dev, Error **errp)
rtc_set_date_from_host(isadev);
+ qemu_mutex_init(&s->rtc_lock);
+
switch (s->lost_tick_policy) {
#ifdef TARGET_I386
case LOST_TICK_POLICY_SLEW:
@@ -986,6 +1024,7 @@ static void rtc_realizefn(DeviceState *dev, Error **errp)
qemu_register_suspend_notifier(&s->suspend_notifier);
memory_region_init_io(&s->io, OBJECT(s), &cmos_ops, s, "rtc", 2);
+ memory_region_clear_global_locking(&s->io);
isa_register_ioport(isadev, &s->io, base);
qdev_set_legacy_instance_id(dev, base, 3);
--
1.8.3.1
Ping...
Regards,
-Gonglei
> -----Original Message-----
> From: Gonglei (Arei)
> Sent: Monday, February 12, 2018 4:58 PM
> To: qemu-devel@nongnu.org
> Cc: pbonzini@redhat.com; Huangweidong (C); peter.maydell@linaro.org;
> Gonglei (Arei)
> Subject: [PATCH v3] rtc: placing RTC memory region outside BQL
>
> As windows guest use rtc as the clock source device,
> and access rtc frequently. Let's move the rtc memory
> region outside BQL to decrease overhead for windows guests.
> Meanwhile, adding a new lock to avoid different vCPUs
> access the RTC together.
>
> I tested PCMark 8 (https://www.futuremark.com/benchmarks/pcmark)
> in win7 guest and got the below results:
>
> Guest: 2U2G
>
> Before applying the patch:
>
> Your Work 2.0 score: 2000
> Web Browsing - JunglePin 0.334s
> Web Browsing - Amazonia 0.132s
> Writing 3.59s
> Spreadsheet 70.13s
> Video Chat v2/Video Chat playback 1 v2 22.8 fps
> Video Chat v2/Video Chat encoding v2 307.0 ms
> Benchmark duration 1h 35min 46s
>
> After applying the patch:
>
> Your Work 2.0 score: 2040
> Web Browsing - JunglePin 0.345s
> Web Browsing - Amazonia 0.132s
> Writing 3.56s
> Spreadsheet 67.83s
> Video Chat v2/Video Chat playback 1 v2 28.7 fps
> Video Chat v2/Video Chat encoding v2 324.7 ms
> Benchmark duration 1h 32min 5s
>
> Test results show that optimization is effective under
> stressful situations.
>
> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
> ---
> v3->v2:
> a) fix a typo, 's/rasie/raise/' [Peter]
> b) change commit message [Peter]
>
> v2->v1:
> a)Adding a new lock to avoid different vCPUs
> access the RTC together. [Paolo]
> b)Taking the BQL before raising the outbound IRQ line. [Peter]
> c)Don't hold BQL if it was holden. [Peter]
>
> hw/timer/mc146818rtc.c | 55
> ++++++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 47 insertions(+), 8 deletions(-)
>
> diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
> index 35a05a6..f0a2a62 100644
> --- a/hw/timer/mc146818rtc.c
> +++ b/hw/timer/mc146818rtc.c
> @@ -85,6 +85,7 @@ typedef struct RTCState {
> uint16_t irq_reinject_on_ack_count;
> uint32_t irq_coalesced;
> uint32_t period;
> + QemuMutex rtc_lock;
> QEMUTimer *coalesced_timer;
> Notifier clock_reset_notifier;
> LostTickPolicy lost_tick_policy;
> @@ -125,6 +126,36 @@ static void rtc_coalesced_timer_update(RTCState *s)
> }
> }
>
> +static void rtc_raise_irq(RTCState *s)
> +{
> + bool unlocked = !qemu_mutex_iothread_locked();
> +
> + if (unlocked) {
> + qemu_mutex_lock_iothread();
> + }
> +
> + qemu_irq_raise(s->irq);
> +
> + if (unlocked) {
> + qemu_mutex_unlock_iothread();
> + }
> +}
> +
> +static void rtc_lower_irq(RTCState *s)
> +{
> + bool unlocked = !qemu_mutex_iothread_locked();
> +
> + if (unlocked) {
> + qemu_mutex_lock_iothread();
> + }
> +
> + qemu_irq_lower(s->irq);
> +
> + if (unlocked) {
> + qemu_mutex_unlock_iothread();
> + }
> +}
> +
> static QLIST_HEAD(, RTCState) rtc_devices =
> QLIST_HEAD_INITIALIZER(rtc_devices);
>
> @@ -141,7 +172,7 @@ void qmp_rtc_reset_reinjection(Error **errp)
> static bool rtc_policy_slew_deliver_irq(RTCState *s)
> {
> apic_reset_irq_delivered();
> - qemu_irq_raise(s->irq);
> + rtc_raise_irq(s);
> return apic_get_irq_delivered();
> }
>
> @@ -277,8 +308,9 @@ static void rtc_periodic_timer(void *opaque)
> DPRINTF_C("cmos: coalesced irqs increased to %d\n",
> s->irq_coalesced);
> }
> - } else
> - qemu_irq_raise(s->irq);
> + } else {
> + rtc_raise_irq(s);
> + }
> }
> }
>
> @@ -459,7 +491,7 @@ static void rtc_update_timer(void *opaque)
> s->cmos_data[RTC_REG_C] |= irqs;
> if ((new_irqs & s->cmos_data[RTC_REG_B]) != 0) {
> s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
> - qemu_irq_raise(s->irq);
> + rtc_raise_irq(s);
> }
> check_update_timer(s);
> }
> @@ -471,6 +503,7 @@ static void cmos_ioport_write(void *opaque, hwaddr
> addr,
> uint32_t old_period;
> bool update_periodic_timer;
>
> + qemu_mutex_lock(&s->rtc_lock);
> if ((addr & 1) == 0) {
> s->cmos_index = data & 0x7f;
> } else {
> @@ -560,10 +593,10 @@ static void cmos_ioport_write(void *opaque,
> hwaddr addr,
> * becomes enabled, raise an interrupt immediately. */
> if (data & s->cmos_data[RTC_REG_C] & REG_C_MASK) {
> s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
> - qemu_irq_raise(s->irq);
> + rtc_raise_irq(s);
> } else {
> s->cmos_data[RTC_REG_C] &= ~REG_C_IRQF;
> - qemu_irq_lower(s->irq);
> + rtc_lower_irq(s);
> }
> s->cmos_data[RTC_REG_B] = data;
>
> @@ -583,6 +616,7 @@ static void cmos_ioport_write(void *opaque, hwaddr
> addr,
> break;
> }
> }
> + qemu_mutex_unlock(&s->rtc_lock);
> }
>
> static inline int rtc_to_bcd(RTCState *s, int a)
> @@ -710,6 +744,7 @@ static uint64_t cmos_ioport_read(void *opaque,
> hwaddr addr,
> if ((addr & 1) == 0) {
> return 0xff;
> } else {
> + qemu_mutex_lock(&s->rtc_lock);
> switch(s->cmos_index) {
> case RTC_IBM_PS2_CENTURY_BYTE:
> s->cmos_index = RTC_CENTURY;
> @@ -737,7 +772,7 @@ static uint64_t cmos_ioport_read(void *opaque,
> hwaddr addr,
> break;
> case RTC_REG_C:
> ret = s->cmos_data[s->cmos_index];
> - qemu_irq_lower(s->irq);
> + rtc_lower_irq(s);
> s->cmos_data[RTC_REG_C] = 0x00;
> if (ret & (REG_C_UF | REG_C_AF)) {
> check_update_timer(s);
> @@ -762,6 +797,7 @@ static uint64_t cmos_ioport_read(void *opaque,
> hwaddr addr,
> }
> CMOS_DPRINTF("cmos: read index=0x%02x val=0x%02x\n",
> s->cmos_index, ret);
> + qemu_mutex_unlock(&s->rtc_lock);
> return ret;
> }
> }
> @@ -909,7 +945,7 @@ static void rtc_reset(void *opaque)
> s->cmos_data[RTC_REG_C] &= ~(REG_C_UF | REG_C_IRQF | REG_C_PF
> | REG_C_AF);
> check_update_timer(s);
>
> - qemu_irq_lower(s->irq);
> + rtc_lower_irq(s);
>
> if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) {
> s->irq_coalesced = 0;
> @@ -960,6 +996,8 @@ static void rtc_realizefn(DeviceState *dev, Error
> **errp)
>
> rtc_set_date_from_host(isadev);
>
> + qemu_mutex_init(&s->rtc_lock);
> +
> switch (s->lost_tick_policy) {
> #ifdef TARGET_I386
> case LOST_TICK_POLICY_SLEW:
> @@ -986,6 +1024,7 @@ static void rtc_realizefn(DeviceState *dev, Error
> **errp)
> qemu_register_suspend_notifier(&s->suspend_notifier);
>
> memory_region_init_io(&s->io, OBJECT(s), &cmos_ops, s, "rtc", 2);
> + memory_region_clear_global_locking(&s->io);
> isa_register_ioport(isadev, &s->io, base);
>
> qdev_set_legacy_instance_id(dev, base, 3);
> --
> 1.8.3.1
>
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