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Diffstat (limited to 'classification_output/05/graphic/46572227')
| -rw-r--r-- | classification_output/05/graphic/46572227 | 414 |
1 files changed, 0 insertions, 414 deletions
diff --git a/classification_output/05/graphic/46572227 b/classification_output/05/graphic/46572227 deleted file mode 100644 index ae72af541..000000000 --- a/classification_output/05/graphic/46572227 +++ /dev/null @@ -1,414 +0,0 @@ -semantic: 0.965 -graphic: 0.962 -mistranslation: 0.946 -assembly: 0.931 -other: 0.927 -instruction: 0.906 -vnc: 0.904 -device: 0.901 -boot: 0.900 -KVM: 0.857 -network: 0.841 -socket: 0.841 - -[Qemu-devel] [Bug?] Windows 7's time drift obviously while RTC rate switching frequently between high and low timer rate - -Hi, - -We tested with the latest QEMU, and found that time drift obviously (clock fast -in guest) -in Windows 7 64 bits guest in some cases. - -It is easily to reproduce, using the follow QEMU command line to start windows -7: - -# x86_64-softmmu/qemu-system-x86_64 -name win7_64_2U_raw -machine -pc-i440fx-2.6,accel=kvm,usb=off -cpu host -m 2048 -realtime mlock=off -smp -4,sockets=2,cores=2,threads=1 -rtc base=utc,clock=vm,driftfix=slew -no-hpet --global kvm-pit.lost_tick_policy=discard -hda /mnt/nfs/win7_sp1_32_2U_raw -vnc -:11 -netdev tap,id=hn0,vhost=off -device rtl8139,id=net-pci0,netdev=hn0 -device -piix3-usb-uhci,id=usb -device usb-tablet,id=input0 -device usb-mouse,id=input1 --device usb-kbd,id=input2 -monitor stdio - -Adjust the VM's time to host time, and run java application or run the follow -program -in windows 7: - -#pragma comment(lib, "winmm") -#include <stdio.h> -#include <windows.h> - -#define SWITCH_PEROID 13 - -int main() -{ - DWORD count = 0; - - while (1) - { - count++; - timeBeginPeriod(1); - DWORD start = timeGetTime(); - Sleep(40); - timeEndPeriod(1); - if ((count % SWITCH_PEROID) == 0) { - Sleep(1); - } - } - return 0; -} - -After few minutes, you will find that the time in windows 7 goes ahead of the -host time, drifts about several seconds. - -I have dug deeper in this problem. For windows systems that use the CMOS timer, -the base interrupt rate is usually 64Hz, but running some application in VM -will raise the timer rate to 1024Hz, running java application and or above -program will raise the timer rate. -Besides, Windows operating systems generally keep time by counting timer -interrupts (ticks). But QEMU seems not emulate the rate converting fine. - -We update the timer in function periodic_timer_update(): -static void periodic_timer_update(RTCState *s, int64_t current_time) -{ - - cur_clock = muldiv64(current_time, RTC_CLOCK_RATE, get_ticks_per_sec()); - next_irq_clock = (cur_clock & ~(period - 1)) + period; - ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -Here we calculate the next interrupt time by align the current clock with the -new period, I'm a little confused that why we care about the *history* time ? -If VM switches from high rate to low rate, the next interrupt time may come -earlier than it supposed to be. We have observed it in our test. we printed the -interval time of interrupts and the VM's current time (We got the time from VM). - -Here is part of the log: -... ... -period=512 irq inject 1534: 15625 us -Tue Mar 29 04:38:00 2016 -*irq_num_period_32=0, irq_num_period_512=64: [3]: Real time interval is 999696 -us -... ... -*irq_num_period_32=893, irq_num_period_512=9 [81]: Real time interval is 951086 -us -Convert 32 --- > 512: 703: 96578 us -period=512 irq inject 44391: 12702 us -Convert 512 --- > 32: 704: 12704 us11 -period=32 irq inject 44392: 979 us -... ... -32 --- > 512: 705: 24388 us -period=512 irq inject 44417: 6834 us -Convert 512 --- > 32: 706: 6830 us -period=32 irq inject 44418: 978 us -... ... -Convert 32 --- > 512: 707: 60525 us -period=512 irq inject 44480: 1945 us -Convert 512 --- > 32: 708: 1955 us -period=32 irq inject 44481: 977 us -... ... -Convert 32 --- > 512: 709: 36105 us -period=512 irq inject 44518: 10741 us -Convert 512 --- > 32: 710: 10736 us -period=32 irq inject 44519: 989 us -... ... -Convert 32 --- > 512: 711: 123998 us -period=512 irq inject 44646: 974 us -period=512 irq inject 44647: 15607 us -Convert 512 --- > 32: 712: 16560 us -period=32 irq inject 44648: 980 us -... ... -period=32 irq inject 44738: 974 us -Convert 32 --- > 512: 713: 88828 us -period=512 irq inject 44739: 4885 us -Convert 512 --- > 32: 714: 4882 us -period=32 irq inject 44740: 989 us -... ... -period=32 irq inject 44842: 974 us -Convert 32 --- > 512: 715: 100537 us -period=512 irq inject 44843: 8788 us -Convert 512 --- > 32: 716: 8789 us -period=32 irq inject 44844: 972 us -... ... -period=32 irq inject 44941: 979 us -Convert 32 --- > 512: 717: 95677 us -period=512 irq inject 44942: 13661 us -Convert 512 --- > 32: 718: 13657 us -period=32 irq inject 44943: 987 us -... ... -Convert 32 --- > 512: 719: 94690 us -period=512 irq inject 45040: 14643 us -Convert 512 --- > 32: 720: 14642 us -period=32 irq inject 45041: 974 us -... ... -Convert 32 --- > 512: 721: 88848 us -period=512 irq inject 45132: 4892 us -Convert 512 --- > 32: 722: 4931 us -period=32 irq inject 45133: 964 us -... ... -Tue Mar 29 04:39:19 2016 -*irq_num_period_32:835, irq_num_period_512:11 [82], Real time interval is -911520 us - -For windows 7, it has got 835 IRQs which injected during the period of 32, -and got 11 IRQs that injected during the period of 512. it updated the -wall-clock -time with one second, because it supposed it has counted -(835*976.5+11*15625)= 987252.5 us, but the real interval time is 911520 us. - -IMHO, we should calculate the next interrupt time based on the time of last -interrupt injected, and it seems to be more similar with hardware CMOS timer -in this way. -Maybe someone can tell me the reason why we calculated the interrupt timer -in that way, or is it a bug ? ;) - -Thanks, -Hailiang - -ping... - -It seems that we can eliminate the drift by the following patch. -(I tested it for two hours, and there is no drift, before, the timer -in Windows 7 drifts about 2 seconds per minute.) I'm not sure if it is -the right way to solve the problem. -Any comments are welcomed. Thanks. - -From bd6acd577cbbc9d92d6376c770219470f184f7de Mon Sep 17 00:00:00 2001 -From: zhanghailiang <address@hidden> -Date: Thu, 31 Mar 2016 16:36:15 -0400 -Subject: [PATCH] timer/mc146818rtc: fix timer drift in Windows OS while RTC - rate converting frequently - -Signed-off-by: zhanghailiang <address@hidden> ---- - hw/timer/mc146818rtc.c | 25 ++++++++++++++++++++++--- - 1 file changed, 22 insertions(+), 3 deletions(-) - -diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c -index 2ac0fd3..e39d2da 100644 ---- a/hw/timer/mc146818rtc.c -+++ b/hw/timer/mc146818rtc.c -@@ -79,6 +79,7 @@ typedef struct RTCState { - /* periodic timer */ - QEMUTimer *periodic_timer; - int64_t next_periodic_time; -+ uint64_t last_periodic_time; - /* update-ended timer */ - QEMUTimer *update_timer; - uint64_t next_alarm_time; -@@ -152,7 +153,8 @@ static void rtc_coalesced_timer(void *opaque) - static void periodic_timer_update(RTCState *s, int64_t current_time) - { - int period_code, period; -- int64_t cur_clock, next_irq_clock; -+ int64_t cur_clock, next_irq_clock, pre_irq_clock; -+ bool change = false; - - period_code = s->cmos_data[RTC_REG_A] & 0x0f; - if (period_code != 0 -@@ -165,14 +167,28 @@ static void periodic_timer_update(RTCState *s, int64_t -current_time) - if (period != s->period) { - s->irq_coalesced = (s->irq_coalesced * s->period) / period; - DPRINTF_C("cmos: coalesced irqs scaled to %d\n", s->irq_coalesced); -+ if (s->period && period) { -+ change = true; -+ } - } - s->period = period; - #endif - /* compute 32 khz clock */ - cur_clock = - muldiv64(current_time, RTC_CLOCK_RATE, NANOSECONDS_PER_SECOND); -+ if (change) { -+ int offset = 0; - -- next_irq_clock = (cur_clock & ~(period - 1)) + period; -+ pre_irq_clock = muldiv64(s->last_periodic_time, RTC_CLOCK_RATE, -+ NANOSECONDS_PER_SECOND); -+ if ((cur_clock - pre_irq_clock) > period) { -+ offset = (cur_clock - pre_irq_clock) / period; -+ } -+ s->irq_coalesced += offset; -+ next_irq_clock = pre_irq_clock + (offset + 1) * period; -+ } else { -+ next_irq_clock = (cur_clock & ~(period - 1)) + period; -+ } - s->next_periodic_time = muldiv64(next_irq_clock, -NANOSECONDS_PER_SECOND, - RTC_CLOCK_RATE) + 1; - timer_mod(s->periodic_timer, s->next_periodic_time); -@@ -187,7 +203,9 @@ static void periodic_timer_update(RTCState *s, int64_t -current_time) - static void rtc_periodic_timer(void *opaque) - { - RTCState *s = opaque; -- -+ int64_t next_periodic_time; -+ -+ next_periodic_time = s->next_periodic_time; - periodic_timer_update(s, s->next_periodic_time); - s->cmos_data[RTC_REG_C] |= REG_C_PF; - if (s->cmos_data[RTC_REG_B] & REG_B_PIE) { -@@ -204,6 +222,7 @@ static void rtc_periodic_timer(void *opaque) - DPRINTF_C("cmos: coalesced irqs increased to %d\n", - s->irq_coalesced); - } -+ s->last_periodic_time = next_periodic_time; - } else - #endif - qemu_irq_raise(s->irq); --- -1.8.3.1 - - -On 2016/3/29 19:58, Hailiang Zhang wrote: -Hi, - -We tested with the latest QEMU, and found that time drift obviously (clock fast -in guest) -in Windows 7 64 bits guest in some cases. - -It is easily to reproduce, using the follow QEMU command line to start windows -7: - -# x86_64-softmmu/qemu-system-x86_64 -name win7_64_2U_raw -machine -pc-i440fx-2.6,accel=kvm,usb=off -cpu host -m 2048 -realtime mlock=off -smp -4,sockets=2,cores=2,threads=1 -rtc base=utc,clock=vm,driftfix=slew -no-hpet --global kvm-pit.lost_tick_policy=discard -hda /mnt/nfs/win7_sp1_32_2U_raw -vnc -:11 -netdev tap,id=hn0,vhost=off -device rtl8139,id=net-pci0,netdev=hn0 -device -piix3-usb-uhci,id=usb -device usb-tablet,id=input0 -device usb-mouse,id=input1 --device usb-kbd,id=input2 -monitor stdio - -Adjust the VM's time to host time, and run java application or run the follow -program -in windows 7: - -#pragma comment(lib, "winmm") -#include <stdio.h> -#include <windows.h> - -#define SWITCH_PEROID 13 - -int main() -{ - DWORD count = 0; - - while (1) - { - count++; - timeBeginPeriod(1); - DWORD start = timeGetTime(); - Sleep(40); - timeEndPeriod(1); - if ((count % SWITCH_PEROID) == 0) { - Sleep(1); - } - } - return 0; -} - -After few minutes, you will find that the time in windows 7 goes ahead of the -host time, drifts about several seconds. - -I have dug deeper in this problem. For windows systems that use the CMOS timer, -the base interrupt rate is usually 64Hz, but running some application in VM -will raise the timer rate to 1024Hz, running java application and or above -program will raise the timer rate. -Besides, Windows operating systems generally keep time by counting timer -interrupts (ticks). But QEMU seems not emulate the rate converting fine. - -We update the timer in function periodic_timer_update(): -static void periodic_timer_update(RTCState *s, int64_t current_time) -{ - - cur_clock = muldiv64(current_time, RTC_CLOCK_RATE, -get_ticks_per_sec()); - next_irq_clock = (cur_clock & ~(period - 1)) + period; - ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -Here we calculate the next interrupt time by align the current clock with the -new period, I'm a little confused that why we care about the *history* time ? -If VM switches from high rate to low rate, the next interrupt time may come -earlier than it supposed to be. We have observed it in our test. we printed the -interval time of interrupts and the VM's current time (We got the time from VM). - -Here is part of the log: -... ... -period=512 irq inject 1534: 15625 us -Tue Mar 29 04:38:00 2016 -*irq_num_period_32=0, irq_num_period_512=64: [3]: Real time interval is 999696 -us -... ... -*irq_num_period_32=893, irq_num_period_512=9 [81]: Real time interval is 951086 -us -Convert 32 --- > 512: 703: 96578 us -period=512 irq inject 44391: 12702 us -Convert 512 --- > 32: 704: 12704 us11 -period=32 irq inject 44392: 979 us -... ... -32 --- > 512: 705: 24388 us -period=512 irq inject 44417: 6834 us -Convert 512 --- > 32: 706: 6830 us -period=32 irq inject 44418: 978 us -... ... -Convert 32 --- > 512: 707: 60525 us -period=512 irq inject 44480: 1945 us -Convert 512 --- > 32: 708: 1955 us -period=32 irq inject 44481: 977 us -... ... -Convert 32 --- > 512: 709: 36105 us -period=512 irq inject 44518: 10741 us -Convert 512 --- > 32: 710: 10736 us -period=32 irq inject 44519: 989 us -... ... -Convert 32 --- > 512: 711: 123998 us -period=512 irq inject 44646: 974 us -period=512 irq inject 44647: 15607 us -Convert 512 --- > 32: 712: 16560 us -period=32 irq inject 44648: 980 us -... ... -period=32 irq inject 44738: 974 us -Convert 32 --- > 512: 713: 88828 us -period=512 irq inject 44739: 4885 us -Convert 512 --- > 32: 714: 4882 us -period=32 irq inject 44740: 989 us -... ... -period=32 irq inject 44842: 974 us -Convert 32 --- > 512: 715: 100537 us -period=512 irq inject 44843: 8788 us -Convert 512 --- > 32: 716: 8789 us -period=32 irq inject 44844: 972 us -... ... -period=32 irq inject 44941: 979 us -Convert 32 --- > 512: 717: 95677 us -period=512 irq inject 44942: 13661 us -Convert 512 --- > 32: 718: 13657 us -period=32 irq inject 44943: 987 us -... ... -Convert 32 --- > 512: 719: 94690 us -period=512 irq inject 45040: 14643 us -Convert 512 --- > 32: 720: 14642 us -period=32 irq inject 45041: 974 us -... ... -Convert 32 --- > 512: 721: 88848 us -period=512 irq inject 45132: 4892 us -Convert 512 --- > 32: 722: 4931 us -period=32 irq inject 45133: 964 us -... ... -Tue Mar 29 04:39:19 2016 -*irq_num_period_32:835, irq_num_period_512:11 [82], Real time interval is -911520 us - -For windows 7, it has got 835 IRQs which injected during the period of 32, -and got 11 IRQs that injected during the period of 512. it updated the -wall-clock -time with one second, because it supposed it has counted -(835*976.5+11*15625)= 987252.5 us, but the real interval time is 911520 us. - -IMHO, we should calculate the next interrupt time based on the time of last -interrupt injected, and it seems to be more similar with hardware CMOS timer -in this way. -Maybe someone can tell me the reason why we calculated the interrupt timer -in that way, or is it a bug ? ;) - -Thanks, -Hailiang - |