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diff --git a/docs/userguide/low_latency.userguide.rst b/docs/userguide/low_latency.userguide.rst deleted file mode 100644 index f027b4939..000000000 --- a/docs/userguide/low_latency.userguide.rst +++ /dev/null @@ -1,264 +0,0 @@ -.. This work is licensed under a Creative Commons Attribution 4.0 International License. - -.. http://creativecommons.org/licenses/by/4.0 - -Low Latency Environment -======================= - -Achieving low latency with the KVM4NFV project requires setting up a special -test environment. This environment includes the BIOS settings, kernel -configuration, kernel parameters and the run-time environment. - -Hardware Environment Description --------------------------------- - -BIOS setup plays an important role in achieving real-time latency. A collection -of relevant settings, used on the platform where the baseline performance data -was collected, is detailed below: - -CPU Features -~~~~~~~~~~~~ - -Some special CPU features like TSC-deadline timer, invariant TSC and Process -posted interrupts, etc, are helpful for latency reduction. - -CPU Topology -~~~~~~~~~~~~ - -NUMA topology is also important for latency reduction. - -BIOS Setup -~~~~~~~~~~ - -Careful BIOS setup is important in achieving real time latency. Different -platforms have different BIOS setups, below are the important BIOS settings on -the platform used to collect the baseline performance data. - -Software Environment Setup --------------------------- -Both the host and the guest environment need to be configured properly to -reduce latency variations. Below are some suggested kernel configurations. -The ci/envs/ directory gives detailed implementation on how to setup the -environment. - -Kernel Parameter -~~~~~~~~~~~~~~~~ - -Please check the default kernel configuration in the source code at: -kernel/arch/x86/configs/opnfv.config. - -Below is host kernel boot line example: - -.. code:: bash - - isolcpus=11-15,31-35 nohz_full=11-15,31-35 rcu_nocbs=11-15,31-35 - iommu=pt intel_iommu=on default_hugepagesz=1G hugepagesz=1G mce=off idle=poll - intel_pstate=disable processor.max_cstate=1 pcie_asmp=off tsc=reliable - -Below is guest kernel boot line example - -.. code:: bash - - isolcpus=1 nohz_full=1 rcu_nocbs=1 mce=off idle=poll default_hugepagesz=1G - hugepagesz=1G - -Please refer to `tuning.userguide` for more explanation. - -Run-time Environment Setup -~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Not only are special kernel parameters needed but a special run-time -environment is also required. Please refer to `tunning.userguide` for -more explanation. - -Test cases to measure Latency ------------------------------ -The performance of the kvm4nfv is assesed by the latency values. Cyclictest and Packet forwarding -Test cases result in real time latency values of average, minimum and maximum. - -* Cyclictest - -* Packet Forwarding test - -1. Cyclictest case -------------------- -Cyclictest results are the most frequently cited real-time Linux metric. The core concept of Cyclictest is very simple. -In KVM4NFV cyclictest is implemented on the Guest-VM with 4.4-Kernel RPM installed. It generated Max,Min and Avg -values which help in assesing the kernel used. Cyclictest in currently divided into the following test types, - -* Idle-Idle -* CPU_stress-Idle -* Memory_stress-Idle -* IO_stress-Idle - -Future scope of work may include the below test-types, - -* CPU_stress-CPU_stress -* Memory_stress-Memory_stress -* IO_stress-IO_stress - -Understanding the naming convention -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -.. code:: bash - - [Host-Type ] - [Guest-Type] - -* **Host-Type :** Mentions the type of stress applied on the kernel of the Host -* **Guest-Type :** Mentions the type of stress applied on the kernel of the Guest - -Example., - -.. code:: bash - - Idle - CPU_stress - -The above name signifies that, - -- No Stress is applied on the Host kernel - -- CPU Stress is applied on the Guest kernel - -**Note:** - -- Stress is applied using the stress which is installed as part of the deployment. - Stress can be applied on CPU, Memory and Input-Output (Read/Write) operations using the stress tool. - -Version Features -~~~~~~~~~~~~~~~~ - -+-----------------------+------------------+-----------------+ -| **Test Name** | **Colorado** | **Danube** | -| | | | -+-----------------------+------------------+-----------------+ -| - Idle - Idle | ``Y`` | ``Y`` | -+-----------------------+------------------+-----------------+ -| - Cpustress - Idle | | ``Y`` | -+-----------------------+------------------+-----------------+ -| - Memorystress - Idle | | ``Y`` | -+-----------------------+------------------+-----------------+ -| - IOstress - Idle | | ``Y`` | -+-----------------------+------------------+-----------------+ - - -Idle-Idle test-type -~~~~~~~~~~~~~~~~~~~ -Cyclictest in run on the Guest VM when Host,Guest are not under any kind of stress. This is the basic -cyclictest of the KVM4NFV project. Outputs Avg, Min and Max latency values. - -.. figure:: images/idle-idle-test-type.png - :name: idle-idle test type - :width: 100% - :align: center - -CPU_Stress-Idle test-type -~~~~~~~~~~~~~~~~~~~~~~~~~ -Here, the host is under CPU stress, where multiple times sqrt() function is called on kernel which -results increased CPU load. The cyclictest will run on the guest, where the guest is under no stress. -Outputs Avg, Min and Max latency values. - -.. figure:: images/cpu-stress-idle-test-type.png - :name: cpu-stress-idle test type - :width: 100% - :align: center - -Memory_Stress-Idle test-type -~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -In this type, the host is under memory stress where continuos memory operations are implemented to -increase the Memory stress (Buffer stress).The cyclictest will run on the guest, where the guest is under -no stress. It outputs Avg, Min and Max latency values. - -.. figure:: images/memory-stress-idle-test-type.png - :name: memory-stress-idle test type - :width: 100% - :align: center - -IO_Stress-Idle test-type -~~~~~~~~~~~~~~~~~~~~~~~~ -The host is under constant Input/Output stress .i.e., multiple read-write operations are invoked to -increase stress. Cyclictest will run on the guest VM that is launched on the same host, where the guest -is under no stress. It outputs Avg, Min and Max latency values. - -.. figure:: images/io-stress-idle-test-type.png - :name: io-stress-idle test type - :width: 100% - :align: center - -CPU_Stress-CPU_Stress test-type -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Not implemented for Danube release. - -Memory_Stress-Memory_Stress test-type -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Not implemented for Danube release. - -IO_Stress-IO_Stress test type -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -Not implemented for Danube release. - -2. Packet Forwarding Test cases -------------------------------- -Packet forwarding is an other test case of Kvm4nfv. It measures the time taken by a packet to return -to source after reaching its destination. This test case uses automated test-framework provided by -OPNFV VSWITCHPERF project and a traffic generator (IXIA is used for kvm4nfv). Only latency results -generating test cases are triggered as a part of kvm4nfv daily job. - -Latency test measures the time required for a frame to travel from the originating device through the -network to the destination device. Please note that RFC2544 Latency measurement will be superseded with -a measurement of average latency over all successfully transferred packets or frames. - -Packet forwarding test cases currently supports the following test types: - -* Packet forwarding to Host - -* Packet forwarding to Guest - -* Packet forwarding to Guest using SRIOV - -The testing approach adoped is black box testing, meaning the test inputs can be generated and the -outputs captured and completely evaluated from the outside of the System Under Test(SUT). - -Packet forwarding to Host -~~~~~~~~~~~~~~~~~~~~~~~~~ -This is also known as Physical port → vSwitch → physical port deployment. -This test measures the time taken by the packet/frame generated by traffic generator(phy) to travel -through the network to the destination device(phy). This test results min,avg and max latency values. -This value signifies the performance of the installed kernel. - -Packet flow, - -.. figure:: images/host_pk_fw.png - :name: packet forwarding to host - :width: 100% - :align: center - -Packet forwarding to Guest -~~~~~~~~~~~~~~~~~~~~~~~~~~ -This is also known as Physical port → vSwitch → VNF → vSwitch → physical port deployment. - -This test measures the time taken by the packet/frame generated by traffic generator(phy) to travel -through the network involving a guest to the destination device(phy). This test results min,avg and -max latency values. This value signifies the performance of the installed kernel. - -Packet flow, - -.. figure:: images/guest_pk_fw.png - :name: packet forwarding to guest - :width: 100% - :align: center - -Packet forwarding to Guest using SRIOV -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -This test is used to verify the VNF and measure the base performance (maximum forwarding rate in -fps and latency) that can be achieved by the VNF without a vSwitch. The performance metrics -collected by this test will serve as a key comparison point for NIC passthrough technologies and -vSwitches. VNF in this context refers to the hypervisor and the VM. - -**Note:** The Vsperf running on the host is still required. - -Packet flow, - -.. figure:: images/sriov_pk_fw.png - :name: packet forwarding to guest using sriov - :width: 100% - :align: center |