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Regards, -Gonglei > -----Original Message----- > From: Gonglei (Arei) > Sent: Monday, February 12, 2018 4:58 PM > To: qemu-devel@nongnu.org > Cc: pbonz...@redhat.com; Huangweidong (C); peter.mayd...@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.gong...@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 >
