Merge branch 'QED-NVMeTCP-Offload'
Shai Malin says: ==================== QED NVMeTCP Offload Intro: ====== This is the qed part of Marvell’s NVMeTCP offload series, shared as RFC series "NVMeTCP Offload ULP and QEDN Device Drive". This part is a standalone series, and is not dependent on other parts of the RFC. The overall goal is to add qedn as the offload driver for NVMeTCP, alongside the existing offload drivers (qedr, qedi and qedf for rdma, iscsi and fcoe respectively). In this series we are making the necessary changes to qed to enable this by exposing APIs for FW/HW initializations. The qedn series (and required changes to NVMe stack) will be sent to the linux-nvme mailing list. I have included more details on the upstream plan under section with the same name below. The Series Patches: =================== 1. qed: Add TCP_ULP FW resource layout – replacing iSCSI when common with NVMeTCP. 2. qed: Add NVMeTCP Offload PF Level FW and HW HSI. 3. qed: Add NVMeTCP Offload Connection Level FW and HW HSI. 4. qed: Add support of HW filter block – enables redirecting NVMeTCP traffic to the dedicated PF. 5. qed: Add NVMeTCP Offload IO Level FW and HW HSI. 6. qed: Add NVMeTCP Offload IO Level FW Initializations. 7. qed: Add IP services APIs support –VLAN, IP routing and reserving TCP ports for the offload device. The NVMeTCP Offload: ==================== With the goal of enabling a generic infrastructure that allows NVMe/TCP offload devices like NICs to seamlessly plug into the NVMe-oF stack, this patch series introduces the nvme-tcp-offload ULP host layer, which will be a new transport type called "tcp-offload" and will serve as an abstraction layer to work with vendor specific nvme-tcp offload drivers. NVMeTCP offload is a full offload of the NVMeTCP protocol, this includes both the TCP level and the NVMeTCP level. The nvme-tcp-offload transport can co-exist with the existing tcp and other transports. The tcp offload was designed so that stack changes are kept to a bare minimum: only registering new transports. All other APIs, ops etc. are identical to the regular tcp transport. Representing the TCP offload as a new transport allows clear and manageable differentiation between the connections which should use the offload path and those that are not offloaded (even on the same device). The nvme-tcp-offload layers and API compared to nvme-tcp and nvme-rdma: * NVMe layer: * [ nvme/nvme-fabrics/blk-mq ] | (nvme API and blk-mq API) | | * Vendor agnostic transport layer: * [ nvme-rdma ] [ nvme-tcp ] [ nvme-tcp-offload ] | | | (Verbs) | | | | (Socket) | | | | | (nvme-tcp-offload API) | | | | | | * Vendor Specific Driver: * | | | [ qedr ] | | [ qede ] | [ qedn ] Performance: ============ With this implementation on top of the Marvell qedn driver (using the Marvell FastLinQ NIC), we were able to demonstrate the following CPU utilization improvement: On AMD EPYC 7402, 2.80GHz, 28 cores: - For 16K queued read IOs, 16jobs, 4qd (50Gbps line rate): Improved the CPU utilization from 15.1% with NVMeTCP SW to 4.7% with NVMeTCP offload. On Intel(R) Xeon(R) Gold 5122 CPU, 3.60GHz, 16 cores: - For 512K queued read IOs, 16jobs, 4qd (25Gbps line rate): Improved the CPU utilization from 16.3% with NVMeTCP SW to 1.1% with NVMeTCP offload. In addition, we were able to demonstrate the following latency improvement: - For 200K read IOPS (16 jobs, 16 qd, with fio rate limiter): Improved the average latency from 105 usec with NVMeTCP SW to 39 usec with NVMeTCP offload. Improved the 99.99 tail latency from 570 usec with NVMeTCP SW to 91 usec with NVMeTCP offload. The end-to-end offload latency was measured from fio while running against back end of null device. The Marvell FastLinQ NIC HW engine: ==================================== The Marvell NIC HW engine is capable of offloading the entire TCP/IP stack and managing up to 64K connections per PF, already implemented and upstream use cases for this include iWARP (by the Marvell qedr driver) and iSCSI (by the Marvell qedi driver). In addition, the Marvell NIC HW engine offloads the NVMeTCP queue layer and is able to manage the IO level also in case of TCP re-transmissions and OOO events. The HW engine enables direct data placement (including the data digest CRC calculation and validation) and direct data transmission (including data digest CRC calculation). The Marvell qedn driver: ======================== The new driver will be added under "drivers/nvme/hw" and will be enabled by the Kconfig "Marvell NVM Express over Fabrics TCP offload". As part of the qedn init, the driver will register as a pci device driver and will work with the Marvell fastlinQ NIC. As part of the probe, the driver will register to the nvme_tcp_offload (ULP) and to the qed module (qed_nvmetcp_ops) - similar to other "qed_*_ops" which are used by the qede, qedr, qedf and qedi device drivers. Upstream Plan: ============= The RFC series "NVMeTCP Offload ULP and QEDN Device Driver" https://lore.kernel.org/netdev/20210531225222.16992-1-smalin@marvell.com/ was designed in a modular way so that part 1 (nvme-tcp-offload) and part 2 (qed) are independent and part 3 (qedn) depends on both parts 1+2. - Part 1 (RFC patch 1-8): NVMeTCP Offload ULP The nvme-tcp-offload patches, will be sent to 'linux-nvme@lists.infradead.org'. - Part 2 (RFC patches 9-15): QED NVMeTCP Offload The qed infrastructure, will be sent to 'netdev@vger.kernel.org'. Once part 1 and 2 are accepted: - Part 3 (RFC patches 16-27): QEDN NVMeTCP Offload The qedn patches, will be sent to 'linux-nvme@lists.infradead.org'. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
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