From: Yuan Liu <yuan1....@intel.com> add Intel QATzip compression method introduction
Signed-off-by: Yuan Liu <yuan1....@intel.com> Reviewed-by: Nanhai Zou <nanhai....@intel.com> Reviewed-by: Peter Xu <pet...@redhat.com> Reviewed-by: Yichen Wang <yichen.w...@bytedance.com> --- docs/devel/migration/features.rst | 1 + docs/devel/migration/qatzip-compression.rst | 251 ++++++++++++++++++++ 2 files changed, 252 insertions(+) create mode 100644 docs/devel/migration/qatzip-compression.rst diff --git a/docs/devel/migration/features.rst b/docs/devel/migration/features.rst index 58f8fd9e16..8f431d52f9 100644 --- a/docs/devel/migration/features.rst +++ b/docs/devel/migration/features.rst @@ -14,3 +14,4 @@ Migration has plenty of features to support different use cases. CPR qpl-compression uadk-compression + qatzip-compression diff --git a/docs/devel/migration/qatzip-compression.rst b/docs/devel/migration/qatzip-compression.rst new file mode 100644 index 0000000000..72fa3e2826 --- /dev/null +++ b/docs/devel/migration/qatzip-compression.rst @@ -0,0 +1,251 @@ +================== +QATzip Compression +================== +In scenarios with limited network bandwidth, the ``QATzip`` solution can help +users save a lot of host CPU resources by accelerating compression and +decompression through the Intel QuickAssist Technology(``QAT``) hardware. + +``QATzip`` is a user space library which builds on top of the Intel QuickAssist +Technology user space library, to provide extended accelerated compression and +decompression services. + +For more ``QATzip`` introduction, please refer to `QATzip Introduction +<https://github.com/intel/QATzip?tab=readme-ov-file#introductionl>`_ + +QATzip Compression Framework +============================ + +:: + + +----------------+ + | MultiFd Thread | + +-------+--------+ + | + | compress/decompress + +-------+--------+ + | QATzip library | + +-------+--------+ + | + +-------+--------+ + | QAT library | + +-------+--------+ + | user space + --------+--------------------- + | kernel space + +------+-------+ + | QAT Driver | + +------+-------+ + | + +------+-------+ + | QAT Devices | + +--------------+ + + +QATzip Installation +------------------- + +The ``QATzip`` installation package has been integrated into some Linux +distributions and can be installed directly. For example, the Ubuntu Server +24.04 LTS system can be installed using below command + +.. code-block:: shell + + #apt search qatzip + libqatzip-dev/noble 1.2.0-0ubuntu3 amd64 + Intel QuickAssist user space library development files + + libqatzip3/noble 1.2.0-0ubuntu3 amd64 + Intel QuickAssist user space library + + qatzip/noble,now 1.2.0-0ubuntu3 amd64 [installed] + Compression user-space tool for Intel QuickAssist Technology + + #sudo apt install libqatzip-dev libqatzip3 qatzip + +If your system does not support the ``QATzip`` installation package, you can +use the source code to build and install, please refer to `QATzip source code installation +<https://github.com/intel/QATzip?tab=readme-ov-file#build-intel-quickassist-technology-driver>`_ + +QAT Hardware Deployment +----------------------- + +``QAT`` supports physical functions(PFs) and virtual functions(VFs) for +deployment, and users can configure ``QAT`` resources for migration according +to actual needs. For more details about ``QAT`` deployment, please refer to +`Intel QuickAssist Technology Documentation +<https://intel.github.io/quickassist/index.html>`_ + +For more ``QAT`` hardware introduction, please refer to `intel-quick-assist-technology-overview +<https://www.intel.com/content/www/us/en/architecture-and-technology/intel-quick-assist-technology-overview.html>`_ + +How To Use QATzip Compression +============================= + +1 - Install ``QATzip`` library + +2 - Build ``QEMU`` with ``--enable-qatzip`` parameter + + E.g. configure --target-list=x86_64-softmmu --enable-kvm ``--enable-qatzip`` + +3 - Set ``migrate_set_parameter multifd-compression qatzip`` + +4 - Set ``migrate_set_parameter multifd-qatzip-level comp_level``, the default +comp_level value is 1, and it supports levels from 1 to 9 + + +Performance Testing with QATzip +=============================== + +Testing environment is being set as below: + +VM configuration:16 vCPU, 64G memory; + +VM Workload: all vCPUs are idle and 54G memory is filled with Silesia data; + +QAT Devices: 4; + +Sender migration parameters: + +.. code-block:: shell + + migrate_set_capability multifd on + migrate_set_parameter multifd-channels 2/4/8 + migrate_set_parameter max-bandwidth 1G/10G + migrate_set_parameter multifd-compression qatzip/zstd + +Receiver migration parameters: + +.. code-block:: shell + + migrate_set_capability multifd on + migrate_set_parameter multifd-channels 2 + migrate_set_parameter multifd-compression qatzip/zstd + +max-bandwidth: 1 GBps (Gbytes/sec) + +.. code-block:: text + + |-----------|--------|---------|----------|------|------| + |2 Channels |Total |down |throughput| send | recv | + | |time(ms)|time(ms) |(mbps) | cpu %| cpu% | + |-----------|--------|---------|----------|------|------| + |qatzip | 21607| 77| 8051| 88| 125| + |-----------|--------|---------|----------|------|------| + |zstd | 78351| 96| 2199| 204| 80| + |-----------|--------|---------|----------|------|------| + + |-----------|--------|---------|----------|------|------| + |4 Channels |Total |down |throughput| send | recv | + | |time(ms)|time(ms) |(mbps) | cpu %| cpu% | + |-----------|--------|---------|----------|------|------| + |qatzip | 20336| 25| 8557| 110| 190| + |-----------|--------|---------|----------|------|------| + |zstd | 39324| 31| 4389| 406| 160| + |-----------|--------|---------|----------|------|------| + + |-----------|--------|---------|----------|------|------| + |8 Channels |Total |down |throughput| send | recv | + | |time(ms)|time(ms) |(mbps) | cpu %| cpu% | + |-----------|--------|---------|----------|------|------| + |qatzip | 20208| 22| 8613| 125| 300| + |-----------|--------|---------|----------|------|------| + |zstd | 20515| 22| 8438| 800| 340| + |-----------|--------|---------|----------|------|------| + +max-bandwidth: 10 GBps (Gbytes/sec) + +.. code-block:: text + + |-----------|--------|---------|----------|------|------| + |2 Channels |Total |down |throughput| send | recv | + | |time(ms)|time(ms) |(mbps) | cpu %| cpu% | + |-----------|--------|---------|----------|------|------| + |qatzip | 22450| 77| 7748| 80| 125| + |-----------|--------|---------|----------|------|------| + |zstd | 78339| 76| 2199| 204| 80| + |-----------|--------|---------|----------|------|------| + + |-----------|--------|---------|----------|------|------| + |4 Channels |Total |down |throughput| send | recv | + | |time(ms)|time(ms) |(mbps) | cpu %| cpu% | + |-----------|--------|---------|----------|------|------| + |qatzip | 13017| 24| 13401| 180| 285| + |-----------|--------|---------|----------|------|------| + |zstd | 39466| 21| 4373| 406| 160| + |-----------|--------|---------|----------|------|------| + + |-----------|--------|---------|----------|------|------| + |8 Channels |Total |down |throughput| send | recv | + | |time(ms)|time(ms) |(mbps) | cpu %| cpu% | + |-----------|--------|---------|----------|------|------| + |qatzip | 10255| 22| 17037| 280| 590| + |-----------|--------|---------|----------|------|------| + |zstd | 20126| 77| 8595| 810| 340| + |-----------|--------|---------|----------|------|------| + +max-bandwidth: 1.25 GBps (Gbytes/sec) + +.. code-block:: text + + |-----------|--------|---------|----------|----------|------|------| + |8 Channels |Total |down |throughput|pages per | send | recv | + | |time(ms)|time(ms) |(mbps) |second | cpu %| cpu% | + |-----------|--------|---------|----------|----------|------|------| + |qatzip | 16630| 28| 10467| 2940235| 160| 360| + |-----------|--------|---------|----------|----------|------|------| + |zstd | 20165| 24| 8579| 2391465| 810| 340| + |-----------|--------|---------|----------|----------|------|------| + |none | 46063| 40| 10848| 330240| 45| 85| + |-----------|--------|---------|----------|----------|------|------| + +If the user has enabled compression in live migration, using QAT can save the +host CPU resources. + +When compression is enabled, the bottleneck of migration is usually the +compression throughput on the sender side, since CPU decompression throughput +is higher than compression, some reference data +https://github.com/inikep/lzbench, so more CPU resources need to be allocated +to the sender side. + +Summary: + +1. In the 1GBps case, QAT only uses 88% CPU utilization to reach 1GBps, but + ZSTD needs 800%. + +2. In the 10Gbps case, QAT uses 180% CPU utilization to reach 10GBps. but ZSTD + still cannot reach 10Gbps even if it uses 810%. + +3. The QAT decompression CPU utilization is higher than compression and ZSTD, + because: + + a. When using QAT compression, the data needs to be copied to the QAT memory + (for DMA operations), and the same for decompression. However, + do_user_addr_fault will be triggered during decompression because the QAT + decompressed data is copied to the VM address space for the first time, in + addition, both compression and decompression are processed by QAT and do not + consume CPU resources, so the CPU utilization of the receiver is slightly + higher than the sender. + + b. Since zstd decompression decompresses data directly into the VM address + space, there is one less memory copy than QAT, so the CPU utilization on the + receiver is better than QAT. For the 1GBps case, the receiver CPU + utilization is 125%, and the memory copy occupies ~80% of CPU utilization. + +How To Choose Between QATzip and QPL +==================================== +Starting from Intel 4th Gen Intel Xeon Scalable processors, codenamed Sapphire +Rapids processor(``SPR``), it supports multiple build-in accelerators including +``QAT`` and ``IAA``, the former can accelerate ``QATzip``, and the latter is +used to accelerate ``QPL``. + +Here are some suggestions: + +1 - If your live migration scenario is limited network bandwidth and ``QAT`` +hardware resources exceed ``IAA``, then use the ``QATzip`` method, which +can save a lot of host CPU resources for compression. + +2 - If your system cannot support shared virtual memory(SVM) technology, please +use ``QATzip`` method because ``QPL`` performance is not good without SVM +support. + +3 - For other scenarios, please use the ``QPL`` method first. -- Yichen Wang