EOI_INDUCEDivybridge
ivybridge 时间:2021-03-28 阅读:()
MessagePassingWorkloadsinKVMDavidMatlack,dmatlack@google.
com1MessagePassingWorkloadsLoopbackTCP_RRIPIandHLTDISCLAIMER:x86andIntelVT-xHaltPollingInterruptsandquestionsarewelcome!
Overview2Usually,anythingthatfrequentlyswitchesbetweenrunningandidle.
Event-drivenworkloadsMemcacheLAMPserversRedisMultithreadedworkloadsusinglowlatencywait/signalprimitivesforcoordination.
WindowsEventObjectspthread_cond_wait/pthread_cond_signalInter-processcommunicationTCP_RR(benchmark)MessagePassingWorkloads3Intuition:Workloadswhichdon'tinvolveIOvirtualizationshouldrunatnearnativeperformance.
Reality:MessagePassingWorkloadsmaynotinvolveanyIObutwillstillperformnXworsethannative.
(loopback)Memcache:2xhigherlatency.
WindowsEventObjects:3-4xhigherlatency.
MessagePassingWorkloads4MessagePassingWorkloads2.
Receive1bytefromclient.
Send1byteback.
1.
Send1bytetoserver.
3.
Receive1bytefromserver.
Microbenchmark:LoopbackTCP_RRClientandServerping-pong1-byteofdataoveranestablishedTCPconnection.
Loopback:Nonetworkingdevices(realorvirtual)involved.
Performance:Latencyofeachtransaction.
Onetransaction:(idle)(idle)(idle)ClientServer5LoopbackTCP_RRPerformance6Host:IvyBridge3.
11KernelGuest:DebianWheezyBackports(3.
16Kernel)3xhigherlatency25usslowerMessagePassingon1CPUContextSwitchMessagePassingon>1CPUInterprocessor-InterruptsWhat'sgoingonunderthehoodVMEXITsareagoodplacetostartlooking.
KVMhasbuilt-inVMEXITcountersandtimers.
perf-kvm(1)VirtualOverheadsofTCP_RR7VirtualOverheadsofTCP_RRTotalNumberofVMEXITsVMEXITs/Transaction1VCPU2VCPU1VCPU2VCPUEXTERNAL_INTERRUPT16705123710.
020.
07MSR_WRITE259917043340.
009.
58IO_INSTRUCTION17867620.
000.
00EOI_INDUCED613250.
000.
00EXCEPTION_NMI289310.
000.
00CPUID2521120.
000.
00CR_ACCESS1712720.
000.
00HLT343543930.
001.
99EPT_VIOLATION200.
000.
00PAUSE_INSTRUCTION020140.
000.
012HLTperTransaction10MSR_WRITEperTransaction8HLTsofTCP_RR2HLTCPUinstruction.
StopexecutinginstructionsonthisCPUuntilaninterruptarrives.
VCPUwishestostopexecutinginstructions.
GuestOShasdecidedthatthereisnothingtodo.
Nothingtodo==idle.
Messagepassingworkloadsswitchbetweenrunningandidle.
.
.
910MSR_WRITE"WritetoModelSpecificRegister"instructionexecutedintheguest.
8APICTimer"InitialCount"Register(MSR838)Writtentostartaper-CPUtimer.
"Startcountingdownandfireaninterruptwhenyougettozero.
"ArtifactofNOHZguestkernel.
2APICInterruptCommandRegister(MSR830)Usedtosendinterprocessor-interrupts(IPI).
Usedtodeliver"messages"betweenclient/serverprocessesrunningonseparateCPUs.
MSR_WRITEsofTCP_RR10VMEXITsofTCP_RRVMEXITSAPICTimerRegisterAPICInterruptCommandRegister(IPI)HLTclientclientidleserveridleidle1.
Send1bytetoserver.
Waitforresponse.
2.
Receive1bytefromclient.
Send1byteback.
3.
Receive1bytefromserver.
VCPU0VCPU111HLTHLTHLTIPIIPIAPICTIMERAPICTIMERAPICTIMERAPICTIMERVMEXITsofTCP_RRVMEXITSAPICTimerRegisterAPICInterruptCommandRegister(IPI)HLTclientclientidleserveridleidle1.
Send1bytetoserver.
Waitforresponse.
2.
Receive1bytefromclient.
Send1byteback.
3.
Receive1bytefromserver.
VCPU0VCPU112HLTHLTHLTIPIIPIAPICTIMERAPICTIMERAPICTIMERAPICTIMERCriticalPath8pertransaction4onthecriticalpathNOHZ(ticklessguestkernel)"Disable"scheduler-tickuponenteringidle.
"Enable"scheduler-tickuponleavingidle.
scheduler-tick==APICTimer(couldalsobeTSCDeadlineTimer)Why2writespertransitioninto/outofidlehrtimer_cancelhrtimer_startAdds3-5ustoround-triplatency.
APICTimer"InitialCount"Register13HLT:x86Instruction.
CPUstopsexecutinginstructionsuntilaninterruptarrives.
ThispartofHLTisnotonthecriticalpath!
HowitworksinKVMPlaceVCPUthreadonawaitqueue.
YieldtheCPUtoanotherthread.
HLTkvm_vcpu_block->schedule()VMEXITHLTcontextswitchtoanotherusertask,kernelthread,oridleVCPU(guest)PCPU(KVM)14kvm_sched_outSendinganIPItowakeupaHLT-edCPU.
Onthecriticalpath!
IPI+HLTWRMSR:APICInterruptCommandRegisterkvm_vcpu_kickreturnfromschedule()inkvm_vcpu_block()vmx_vcpu_runIPIISRVMEXITVMRESUMEVCPU1VCPU0(HLT-ed)guesthostkvm_sched_in*VMEXITandVMRESUMEimplementedinHardware.
time15SendinganIPItowakeupaHLT-edCPU.
Onthecriticalpath!
Sameoperationonbaremetalisentirelyimplementedinhardware.
HowmuchoverheadfromvirtualizationUnlikeAPIC_TMICT,can'tjusttimeVMEXITs.
Wecancomparewiththesameoperationonphysicalhardware.
IPI+HLT16KVMversusHardwareRing0Microbenchmark(kvm-unit-tests)1.
VCPU0:HLT.
2.
~100usdelay3.
VCPU1:A=RDTSC4.
VCPU1:SendIPIto[V]CPU0.
5.
VCPU0:B=RDTSC(firstinstructionofIPIISR).
6.
Latency=B-A7.
Repeat.
RuninKVMguestandonbare-metal.
Compare!
17VMRESUMEWRMSRkvm_vcpu_kickreturnfromschedule()inkvm_vcpu_block()vmx_vcpu_runIPIISRVMEXITVCPU1VCPU0(HLT-ed)guesthostkvm_sched_intimeKVMversusHardwareA=RDTSCB=RDTSC18Median:KVMis12xslowerPathologicalcase(witnessed):KVMis400xslowerBestcase(witnessed):KVMis11xslowerKVM:5.
7us;Hardware:0.
5usKVMversusHardwareCyclesKVMHardwareMin137001200Average15800120050%ile14900120090%ile16000130099%ile249001300Max5210001400Host:SandyBridge@2.
6GHz3.
11KernelKVMperformanceissimilaronIvyBridge(5.
6us)andHaswell(4.
9us).
19Notesaboutthisbenchmark:NoguestFPUtosave/restore.
Hostotherwiseidle(VCPUcontextswitchestoidleonHLT).
Hostpowermanagementnottheculprit.
KVMversusHardware20KVMHLTInternalsSoKVMisslowatdeliveringIPIsand/orcomingoutofHLT.
ButwhyPossibleculprits:WRMSRvmx_vcpu_runIPIISRVMEXITVMRESUMEVCPU1VCPU0(HLT-ed)kvm_sched_intimereturnfromschedule()inkvm_vcpu_block()kvm_vcpu_kick21VMRESUMEvmx_vcpu_runkvm_vcpu_kickKVMHLTInternalsSoKVMisslowatdeliveringIPIsand/orcomingoutofHLT.
ButwhyPossibleculprits:WRMSRIPIISRVMEXITVCPU1VCPU0(HLT-ed)kvm_sched_intimereturnfromschedule()inkvm_vcpu_block()22RDTSCRDTSCRDTSCRDTSCRDTSCKVMHLTInternalsWRMSRkvm_vcpu_kickreturnfromschedule()inkvm_vcpu_block()vmx_vcpu_runIPIISRVMEXITVMRESUMEMin(cycles):400600730032001300VCPU1VCPU0guesthostVT-xKVMSchedulerkvm_sched_in:4924001200850034001400Median(cycles):23Unsurprisingly,theschedulertakessometimetoruntheVCPUSlowevenintheuncontended,cache-hot,case.
ImagineiftheVCPUiscontendingforCPUtimewithotherthreads.
Experiment:Don'tscheduleonHLT.
JustpollfortheIPIinkvm_vcpu_block.
KVMHLTInternals24Whathappenswhenyoudon'tscheduleonHLTKVM(Alwaysschedule)5.
7usKVM(Neverschedule)1.
7usHardware(SandyBridge)0.
5usNeverschedule!
CyclesKVM(Alwaysschedule)KVM(Neverschedule)HardwareMin1380040001200Average158004400120050%ile149004300120090%ile160004500130099%ile2490069001300Max52100050000140025SimilarimprovementsonIvyBridge(5.
6us->1.
6us)Haswell(4.
9us->1.
5us).
Neverschedule!
WRMSRkvm_vcpu_kickreturnfromschedule()inkvm_vcpu_block()vmx_vcpu_runIPIISRVMEXITVMRESUMEAlwaysschedule:4001200850034001400VCPU1VCPU0guesthostVT-xKVMSchedulerNeverschedule:300130011004001200(mediancycles)26Neverschedule!
WeeliminatealmostallofthelatencyoverheadbynotschedulingonHLT.
Schedulingisoftentherightthingtodo.
LetotherthreadsrunorsavehostCPUpower.
Mostofthetimeimprovesguestperformance(lettheIOthreadsrun!
).
Canhurtperformance.
Seemicrobenchmark.
SeeTCP_RR.
27Halt-PollingStep1:PollForuptoXnanoseconds:IfataskiswaitingtorunonourCPU,gotoStep2.
Checkifaguestinterruptarrived.
Ifso,wearedone.
Repeat.
Step2:schedule()Scheduleoutuntilit'stimetocomeoutofHLT.
Pros:WorksonshortHLTs(Cons:IncreasesCPUusage(~1%foridleVCPUsifX=200,000ns)Doesnotappeartonegativelyaffectturboofactivecores.
28Halt-PollingMemcache:1.
5xlatencyimprovementWindowsEventObjects:2xlatencyimprovementReducemessagepassinglatencyby10-15us(includingnetworklatency).
29Halt-PollingMergedintothe4.
0kernel[PATCH]kvm:addhalt_poll_nsmoduleparameterThankstoPaoloBonziniUsetheKVMmoduleparameterhalt_poll_nstocontrolhowlongtopolloneachHLT.
Futureimprovements:Automaticpolltoggling(removeidleCPUoverheadbyturningpollingoff).
Automatichalt_poll_nsKVMwillset(andvary)halt_poll_nsdynamically.
Howtodothisisanopenquestion.
.
.
ideasLazyContextSwitchingEquivalentfeature,butavailableforanykernelcomponenttouse.
30ConclusionMessagePassingEvenloopbackmessagepassingrequiresvirtualization.
Beingidle(asaLinuxguest)requiresvirtualization.
Cross-CPUcommunicationrequiresvirtualization.
Halt-Pollingsaves10-15usonmessagepassinground-triplatency.
Remaininground-triplatency:4MSRwritestotheAPICtimer(3-5us)IPIsend(~2us)HLTwakeup(evenwithhalt-polling,stilladds~3us!
)31
com1MessagePassingWorkloadsLoopbackTCP_RRIPIandHLTDISCLAIMER:x86andIntelVT-xHaltPollingInterruptsandquestionsarewelcome!
Overview2Usually,anythingthatfrequentlyswitchesbetweenrunningandidle.
Event-drivenworkloadsMemcacheLAMPserversRedisMultithreadedworkloadsusinglowlatencywait/signalprimitivesforcoordination.
WindowsEventObjectspthread_cond_wait/pthread_cond_signalInter-processcommunicationTCP_RR(benchmark)MessagePassingWorkloads3Intuition:Workloadswhichdon'tinvolveIOvirtualizationshouldrunatnearnativeperformance.
Reality:MessagePassingWorkloadsmaynotinvolveanyIObutwillstillperformnXworsethannative.
(loopback)Memcache:2xhigherlatency.
WindowsEventObjects:3-4xhigherlatency.
MessagePassingWorkloads4MessagePassingWorkloads2.
Receive1bytefromclient.
Send1byteback.
1.
Send1bytetoserver.
3.
Receive1bytefromserver.
Microbenchmark:LoopbackTCP_RRClientandServerping-pong1-byteofdataoveranestablishedTCPconnection.
Loopback:Nonetworkingdevices(realorvirtual)involved.
Performance:Latencyofeachtransaction.
Onetransaction:(idle)(idle)(idle)ClientServer5LoopbackTCP_RRPerformance6Host:IvyBridge3.
11KernelGuest:DebianWheezyBackports(3.
16Kernel)3xhigherlatency25usslowerMessagePassingon1CPUContextSwitchMessagePassingon>1CPUInterprocessor-InterruptsWhat'sgoingonunderthehoodVMEXITsareagoodplacetostartlooking.
KVMhasbuilt-inVMEXITcountersandtimers.
perf-kvm(1)VirtualOverheadsofTCP_RR7VirtualOverheadsofTCP_RRTotalNumberofVMEXITsVMEXITs/Transaction1VCPU2VCPU1VCPU2VCPUEXTERNAL_INTERRUPT16705123710.
020.
07MSR_WRITE259917043340.
009.
58IO_INSTRUCTION17867620.
000.
00EOI_INDUCED613250.
000.
00EXCEPTION_NMI289310.
000.
00CPUID2521120.
000.
00CR_ACCESS1712720.
000.
00HLT343543930.
001.
99EPT_VIOLATION200.
000.
00PAUSE_INSTRUCTION020140.
000.
012HLTperTransaction10MSR_WRITEperTransaction8HLTsofTCP_RR2HLTCPUinstruction.
StopexecutinginstructionsonthisCPUuntilaninterruptarrives.
VCPUwishestostopexecutinginstructions.
GuestOShasdecidedthatthereisnothingtodo.
Nothingtodo==idle.
Messagepassingworkloadsswitchbetweenrunningandidle.
.
.
910MSR_WRITE"WritetoModelSpecificRegister"instructionexecutedintheguest.
8APICTimer"InitialCount"Register(MSR838)Writtentostartaper-CPUtimer.
"Startcountingdownandfireaninterruptwhenyougettozero.
"ArtifactofNOHZguestkernel.
2APICInterruptCommandRegister(MSR830)Usedtosendinterprocessor-interrupts(IPI).
Usedtodeliver"messages"betweenclient/serverprocessesrunningonseparateCPUs.
MSR_WRITEsofTCP_RR10VMEXITsofTCP_RRVMEXITSAPICTimerRegisterAPICInterruptCommandRegister(IPI)HLTclientclientidleserveridleidle1.
Send1bytetoserver.
Waitforresponse.
2.
Receive1bytefromclient.
Send1byteback.
3.
Receive1bytefromserver.
VCPU0VCPU111HLTHLTHLTIPIIPIAPICTIMERAPICTIMERAPICTIMERAPICTIMERVMEXITsofTCP_RRVMEXITSAPICTimerRegisterAPICInterruptCommandRegister(IPI)HLTclientclientidleserveridleidle1.
Send1bytetoserver.
Waitforresponse.
2.
Receive1bytefromclient.
Send1byteback.
3.
Receive1bytefromserver.
VCPU0VCPU112HLTHLTHLTIPIIPIAPICTIMERAPICTIMERAPICTIMERAPICTIMERCriticalPath8pertransaction4onthecriticalpathNOHZ(ticklessguestkernel)"Disable"scheduler-tickuponenteringidle.
"Enable"scheduler-tickuponleavingidle.
scheduler-tick==APICTimer(couldalsobeTSCDeadlineTimer)Why2writespertransitioninto/outofidlehrtimer_cancelhrtimer_startAdds3-5ustoround-triplatency.
APICTimer"InitialCount"Register13HLT:x86Instruction.
CPUstopsexecutinginstructionsuntilaninterruptarrives.
ThispartofHLTisnotonthecriticalpath!
HowitworksinKVMPlaceVCPUthreadonawaitqueue.
YieldtheCPUtoanotherthread.
HLTkvm_vcpu_block->schedule()VMEXITHLTcontextswitchtoanotherusertask,kernelthread,oridleVCPU(guest)PCPU(KVM)14kvm_sched_outSendinganIPItowakeupaHLT-edCPU.
Onthecriticalpath!
IPI+HLTWRMSR:APICInterruptCommandRegisterkvm_vcpu_kickreturnfromschedule()inkvm_vcpu_block()vmx_vcpu_runIPIISRVMEXITVMRESUMEVCPU1VCPU0(HLT-ed)guesthostkvm_sched_in*VMEXITandVMRESUMEimplementedinHardware.
time15SendinganIPItowakeupaHLT-edCPU.
Onthecriticalpath!
Sameoperationonbaremetalisentirelyimplementedinhardware.
HowmuchoverheadfromvirtualizationUnlikeAPIC_TMICT,can'tjusttimeVMEXITs.
Wecancomparewiththesameoperationonphysicalhardware.
IPI+HLT16KVMversusHardwareRing0Microbenchmark(kvm-unit-tests)1.
VCPU0:HLT.
2.
~100usdelay3.
VCPU1:A=RDTSC4.
VCPU1:SendIPIto[V]CPU0.
5.
VCPU0:B=RDTSC(firstinstructionofIPIISR).
6.
Latency=B-A7.
Repeat.
RuninKVMguestandonbare-metal.
Compare!
17VMRESUMEWRMSRkvm_vcpu_kickreturnfromschedule()inkvm_vcpu_block()vmx_vcpu_runIPIISRVMEXITVCPU1VCPU0(HLT-ed)guesthostkvm_sched_intimeKVMversusHardwareA=RDTSCB=RDTSC18Median:KVMis12xslowerPathologicalcase(witnessed):KVMis400xslowerBestcase(witnessed):KVMis11xslowerKVM:5.
7us;Hardware:0.
5usKVMversusHardwareCyclesKVMHardwareMin137001200Average15800120050%ile14900120090%ile16000130099%ile249001300Max5210001400Host:SandyBridge@2.
6GHz3.
11KernelKVMperformanceissimilaronIvyBridge(5.
6us)andHaswell(4.
9us).
19Notesaboutthisbenchmark:NoguestFPUtosave/restore.
Hostotherwiseidle(VCPUcontextswitchestoidleonHLT).
Hostpowermanagementnottheculprit.
KVMversusHardware20KVMHLTInternalsSoKVMisslowatdeliveringIPIsand/orcomingoutofHLT.
ButwhyPossibleculprits:WRMSRvmx_vcpu_runIPIISRVMEXITVMRESUMEVCPU1VCPU0(HLT-ed)kvm_sched_intimereturnfromschedule()inkvm_vcpu_block()kvm_vcpu_kick21VMRESUMEvmx_vcpu_runkvm_vcpu_kickKVMHLTInternalsSoKVMisslowatdeliveringIPIsand/orcomingoutofHLT.
ButwhyPossibleculprits:WRMSRIPIISRVMEXITVCPU1VCPU0(HLT-ed)kvm_sched_intimereturnfromschedule()inkvm_vcpu_block()22RDTSCRDTSCRDTSCRDTSCRDTSCKVMHLTInternalsWRMSRkvm_vcpu_kickreturnfromschedule()inkvm_vcpu_block()vmx_vcpu_runIPIISRVMEXITVMRESUMEMin(cycles):400600730032001300VCPU1VCPU0guesthostVT-xKVMSchedulerkvm_sched_in:4924001200850034001400Median(cycles):23Unsurprisingly,theschedulertakessometimetoruntheVCPUSlowevenintheuncontended,cache-hot,case.
ImagineiftheVCPUiscontendingforCPUtimewithotherthreads.
Experiment:Don'tscheduleonHLT.
JustpollfortheIPIinkvm_vcpu_block.
KVMHLTInternals24Whathappenswhenyoudon'tscheduleonHLTKVM(Alwaysschedule)5.
7usKVM(Neverschedule)1.
7usHardware(SandyBridge)0.
5usNeverschedule!
CyclesKVM(Alwaysschedule)KVM(Neverschedule)HardwareMin1380040001200Average158004400120050%ile149004300120090%ile160004500130099%ile2490069001300Max52100050000140025SimilarimprovementsonIvyBridge(5.
6us->1.
6us)Haswell(4.
9us->1.
5us).
Neverschedule!
WRMSRkvm_vcpu_kickreturnfromschedule()inkvm_vcpu_block()vmx_vcpu_runIPIISRVMEXITVMRESUMEAlwaysschedule:4001200850034001400VCPU1VCPU0guesthostVT-xKVMSchedulerNeverschedule:300130011004001200(mediancycles)26Neverschedule!
WeeliminatealmostallofthelatencyoverheadbynotschedulingonHLT.
Schedulingisoftentherightthingtodo.
LetotherthreadsrunorsavehostCPUpower.
Mostofthetimeimprovesguestperformance(lettheIOthreadsrun!
).
Canhurtperformance.
Seemicrobenchmark.
SeeTCP_RR.
27Halt-PollingStep1:PollForuptoXnanoseconds:IfataskiswaitingtorunonourCPU,gotoStep2.
Checkifaguestinterruptarrived.
Ifso,wearedone.
Repeat.
Step2:schedule()Scheduleoutuntilit'stimetocomeoutofHLT.
Pros:WorksonshortHLTs(
28Halt-PollingMemcache:1.
5xlatencyimprovementWindowsEventObjects:2xlatencyimprovementReducemessagepassinglatencyby10-15us(includingnetworklatency).
29Halt-PollingMergedintothe4.
0kernel[PATCH]kvm:addhalt_poll_nsmoduleparameterThankstoPaoloBonziniUsetheKVMmoduleparameterhalt_poll_nstocontrolhowlongtopolloneachHLT.
Futureimprovements:Automaticpolltoggling(removeidleCPUoverheadbyturningpollingoff).
Automatichalt_poll_nsKVMwillset(andvary)halt_poll_nsdynamically.
Howtodothisisanopenquestion.
.
.
ideasLazyContextSwitchingEquivalentfeature,butavailableforanykernelcomponenttouse.
30ConclusionMessagePassingEvenloopbackmessagepassingrequiresvirtualization.
Beingidle(asaLinuxguest)requiresvirtualization.
Cross-CPUcommunicationrequiresvirtualization.
Halt-Pollingsaves10-15usonmessagepassinground-triplatency.
Remaininground-triplatency:4MSRwritestotheAPICtimer(3-5us)IPIsend(~2us)HLTwakeup(evenwithhalt-polling,stilladds~3us!
)31
- EOI_INDUCEDivybridge相关文档
- slightivybridge
- Revivybridge
- 1.0ivybridge
- 采购ivybridge
- Extreme3ivybridge
- subgroupivybridge
TmhHost香港三网CN2 GIA月付45元起,美国CN2 GIA高防VPS季付99元起
TmhHost是一家国内正规公司，具备ISP\ICP等资质，主营国内外云服务器及独立服务器租用业务，目前，商家新上香港三网CN2 GIA线路VPS及国内镇江BGP高防云主机，其中香港三网CN2 GIA线路最低每月45元起；同时对美国洛杉矶CN2 GIA线路高防及普通VPS进行优惠促销，优惠后美国洛杉矶Cera机房CN2 GIA线路高防VPS季付99元起。香港CN2 GIA安畅机房，三网回程CN2 ...
无忧云( 9.9元/首月),河南洛阳BGP 2核 2G,大连BGP线路 20G高防 ,
无忧云怎么样？无忧云服务器好不好？无忧云值不值得购买？无忧云，无忧云是一家成立于2017年的老牌商家旗下的服务器销售品牌，现由深圳市云上无忧网络科技有限公司运营，是正规持证IDC/ISP/IRCS商家，自营有国内雅安高防、洛阳BGP企业线路、香港CN2线路、国外服务器产品等，非常适合需要稳定的线路的用户，如游戏、企业建站业务需求和各种负载较高的项目，同时还有自营的高性能、高配置的BGP线路高防物理...
CloudCone：洛杉矶MC机房KVM月付1.99美元起,支持支付宝/PayPal
CloudCone是一家成立于2017年的国外VPS主机商，提供独立服务器租用和VPS主机，其中VPS基于KVM架构，多个不同系列，譬如常规VPS、大硬盘VPS等等，数据中心在洛杉矶MC机房。商家2021年Flash Sale活动继续，最低每月1.99美元，支持7天退款到账户，支持使用PayPal或者支付宝付款，先充值后下单的方式。下面列出几款VPS主机配置信息。CPU：1core内存：768MB...
ivybridge为你推荐
-
公司网络被攻击最近企业受到网络攻击的事件特别多，怎么才能有效地保护企业的网络安全呢？小度商城小度分期靠谱吗？firetrap我淘宝店还是卖二单就被删,怎么回事!lunwenjiancepaperfree论文检测怎样算合格seo优化工具SEO优化神器有什么比较好的？lcoc.topoffsettop和scrolltop的区别16668.com香港最快开奖现场直播今晚开dadi.tv电视机如何从iptv转换成tv？www.mfav.org邪恶动态图587期 www.zqzj.org关键词分析怎么样分析关键词？