Deep dive into Kernel

YUM 관련 RPM 소스 다운로드패키지 설치$ yum install yum-plugin-downloadonly사용방법포멧) $ yum install --downloadonly --downloaddir= 예제) $ yum install --downloadonly libvirt-devel.x86_64 --downloaddir=/root/ 또는포멧) $ yumdownloader --source {packagename}예제) $ yumdownloader --source libvirt-devel 또는 RPM 관련 RPM 패키지 풀기 포멧) $ rpm2cpio [rpm 이름] | cpio -ivd예제) $ rpm2cpio libvirt-devel-1.1.1-29.el7.x86_64.rpm | cpio -ivd RP..

Linux Kernel supports CPU isolation for scheduling. edit /etc/default/grub format : isolcpus= GRUB_CMDLINE_LINUX_DEFAULT="isolcpus=0,1" execute grub update $ update-grub In the kernel parameter, we can see linux /vmlinuz-3.13.6+ root=/dev/mapper/gaus02--m--vg-root ro console=ttyS0,115200 earlyprint=serial,ttyS0,115200 pci=assign-busses iommu=pt intel_iommu=on noplymouth text nosplash isolcpus=0,..

MonitorCtrl-L (form feed) can be used to clear the screen in the monitor.More commands support command-line completion. Block devices in system emulationFilenames can be JSON objects preceded by "json:", for example json:{'driver':'raw','file.filename':'test.img'}. This new syntax can be used in the file property for -drive, but also in qemu-io, qemu-img or backing file names.The new "change-bac..

VM 생성시 PV-EOI를 enable 하기 위한 libvirt 설정 파일 sriov-vm 2097152 4 Sunshout KVM 2013.4 hvm qemu command 로 생성할 때는 -cpu +kvm_pv_eoi 를 추가 PV-EOI 를 off 하고 perf 를 통해서 분석한 결과. kvm:kvm_pv_eoi 의 결과가 없음을 확인 root@gaus01-m:/storage# perf stat --event "kvm:*" --all-cpus sleep 10 Performance counter stats for 'system wide': 1,512 kvm:kvm_entry [100.00%] 0 kvm:kvm_hypercall [100.00%] 0 kvm:kvm_hv_hypercall [100.00%..

MSI : Message Signaled Interrupt The bus driver is responsible for initializing the message address and message data of the device function's MSI/MSI-X capability structure during device initial configuration. An MSI capable device function indicates MSI support by implementing the MSI/MSI-X capability structure in its PCI capability list.The MSI capability structure contains Message Control reg..

To enable SR-IOV, need kernel parameter for iommu edit /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="pci=assign-busses iommu=pt intel_iommu=on" Next, execute update-grub $ update-grub On CentOS grub2-mkconfig -o /boot/grub2/grub.cfgIn a Intel machine, check dmesgIntel Machine$dmesg | grep -e DMAR -e IOMMU ... ACPI: DMAR 00000000ac7ebf18 00094 (v01 A M I OEMDMAR 00000001 INTL 00000001) Intel-IOMM..

KVM Interrupt related structures KVM Interrupt Injection to Guest IOAPIC based interrupt delivery MSI interrupt delivery kvm_irq_delivery_to_apic(kvm, NULL, &irq, NULL);- pass no kvm_lapic *src- pass no dest_mapformat : int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, struct kvm_lapic_irq *irq, unsigned long *dest_map) Jul 7 23:10:39 gaus02-m kernel: [49646.052828] # SON MSI ..

ㅇ IO-APIC Interrupts - IO-APIC은 24개의 interrupt line을 가지고 있으며, priority를 설정할 수 있다.- 하위 16개의 interrupt 는 XT-PIC 과 backwards compatibility를 위해서 동작한다. - IO-APIC 은 Local-APIC에 interrupt vector를 씀. 따라서 OS는 IO-APIC과 interaction이 필요하지 않다.EOI를 Notification 할 때만 IO-APIC과 interaction 이 존재한다. interrupted CPU는 interrupt vector 를 받아서 ISR를 실행한다. ㅇ Message Signaled Interrupts- every device to write directly to ..

Interrupt Delivery analysis in KVM with SR-IOV MSI-X 에서 Multiple Queue 로 interrupt 를 전달하는 방법http://www.alexonlinux.com/msi-x-the-right-way-to-spread-interrupt-load