| Message ID | 20210207181324.11429-1-smalin@marvell.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | NVMeTCP Offload ULP and QEDN Device Driver | expand |
On Sun, Feb 07, 2021 at 08:13:13PM +0200, Shai Malin wrote: > Queue Initialization: > ===================== > The nvme-tcp-offload ULP module shall register with the existing > nvmf_transport_ops (.name = "tcp_offload"), nvme_ctrl_ops and blk_mq_ops. > The nvme-tcp-offload vendor driver shall register to nvme-tcp-offload ULP > with the following ops: > - claim_dev() - in order to resolve the route to the target according to > the net_dev. > - create_queue() - in order to create offloaded nvme-tcp queue. > > The nvme-tcp-offload ULP module shall manage all the controller level > functionalities, call claim_dev and based on the return values shall call > the relevant module create_queue in order to create the admin queue and > the IO queues. Hi Shai, How well does this claim_dev approach work with multipathing? Is it expected that providing HOST_TRADDR is sufficient control over which offload device will be used with multiple valid paths to the controller? - Chris
On Fri, 12 Feb 2021 at 20:06, Chris Leech wrote: > > On Sun, Feb 07, 2021 at 08:13:13PM +0200, Shai Malin wrote: > > Queue Initialization: > > ===================== > > The nvme-tcp-offload ULP module shall register with the existing > > nvmf_transport_ops (.name = "tcp_offload"), nvme_ctrl_ops and blk_mq_ops. > > The nvme-tcp-offload vendor driver shall register to nvme-tcp-offload ULP > > with the following ops: > > - claim_dev() - in order to resolve the route to the target according to > > the net_dev. > > - create_queue() - in order to create offloaded nvme-tcp queue. > > > > The nvme-tcp-offload ULP module shall manage all the controller level > > functionalities, call claim_dev and based on the return values shall call > > the relevant module create_queue in order to create the admin queue and > > the IO queues. > > Hi Shai, > > How well does this claim_dev approach work with multipathing? Is it > expected that providing HOST_TRADDR is sufficient control over which > offload device will be used with multiple valid paths to the controller? > > - Chris > Hi Chris, The nvme-tcp-offload multipath behaves the same as the non-offloaded nvme-tcp. The HOST_TRADDR is sufficient to control which offload device will be used with multiple valid paths. - Shai
> > 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). > Sagi, Christoph, Jens, Keith, So, as there are no more comments / questions, we understand the direction is acceptable and will proceed to the full series.
On Thu, Feb 18, 2021 at 06:38:07PM +0000, Shai Malin wrote: > So, as there are no more comments / questions, we understand the direction > is acceptable and will proceed to the full series. I do not think we should support offloads at all, and certainly not onces requiring extra drivers. Those drivers have caused unbelivable pain for iSCSI and we should not repeat that mistake.
> On Thu, Feb 18, 2021 at 06:38:07PM +0000, Shai Malin wrote: > > So, as there are no more comments / questions, we understand the > > direction is acceptable and will proceed to the full series. > > I do not think we should support offloads at all, and certainly not onces > requiring extra drivers. Those drivers have caused unbelivable pain for iSCSI > and we should not repeat that mistake. Hi Christoph, We are fully aware of the challenges the iSCSI offload faced - I was there too (in bnx2i and qedi). In our mind the heart of that hardship was the iSCSI uio design, essentially a thin alternative networking stack, which led to no end of compatibility challenges. But we were also there for RoCE and iWARP (TCP based) RDMA offloads where a different approach was used, working with the networking stack instead of around it. We feel this is a much better approach, and this is what we are attempting to implement here. For this reason exactly we designed this offload to be completely seemless. There is no alternate user stack - we plug in directly into the networking stack and there are zero changes to the regular nvme-tcp. We are just adding a new transport alongside it, which interacts with the networking stack when needed, and leaves it alone most of the time. Our intention is to completely own the maintenance of the new transport, including any compatibility requirements, and have purposefully designed it to be streamlined in this aspect. Protocol offload is at the core of our technology, and our device offloads RoCE, iWARP, iSCSI and FCoE, all already in upstream drivers (qedr, qedi and qedf respectively). We are especially excited about NVMeTCP offload as it brings huge benefits: RDMA-like latency, tremendous cpu utilization reduction and the reliability of TCP. We would be more than happy to incorporate any feedback you may have on the design, in how to make it more robust and correct. We are aware of other work being done in creating special types of offloaded queue, and could model our design similarly, although our thinking was that this would be more intrusive to regular nvme over tcp. In our original submission of the RFC we were not adding a ULP driver, only our own vendor driver, but Sagi pointed us in the direction of a vendor agnostic ulp layer, which made a lot of sense to us and we think is a good approach. Thanks, Ariel
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). Queue Initialization: ===================== The nvme-tcp-offload ULP module shall register with the existing nvmf_transport_ops (.name = "tcp_offload"), nvme_ctrl_ops and blk_mq_ops. The nvme-tcp-offload vendor driver shall register to nvme-tcp-offload ULP with the following ops: - claim_dev() - in order to resolve the route to the target according to the net_dev. - create_queue() - in order to create offloaded nvme-tcp queue. The nvme-tcp-offload ULP module shall manage all the controller level functionalities, call claim_dev and based on the return values shall call the relevant module create_queue in order to create the admin queue and the IO queues. IO-path: ======== The nvme-tcp-offload shall work at the IO-level - the nvme-tcp-offload ULP module shall pass the request (the IO) to the nvme-tcp-offload vendor driver and later, the nvme-tcp-offload vendor driver returns the request completion (the IO completion). No additional handling is needed in between; this design will reduce the CPU utilization as we will describe below. The nvme-tcp-offload vendor driver shall register to nvme-tcp-offload ULP with the following IO-path ops: - init_req() - map_sg() - in order to map the request sg (similar to nvme_rdma_map_data() ). - send_req() - in order to pass the request to the handling of the offload driver that shall pass it to the vendor specific device. - poll_queue() Once the IO completes, the nvme-tcp-offload vendor driver shall call command.done() that will invoke the nvme-tcp-offload ULP layer to complete the request. TCP events: =========== The Marvell FastLinQ NIC HW engine handle all the TCP re-transmissions and OOO events. Teardown and errors: ==================== In case of NVMeTCP queue error the nvme-tcp-offload vendor driver shall call the nvme_tcp_ofld_report_queue_err. The nvme-tcp-offload vendor driver shall register to nvme-tcp-offload ULP with the following teardown ops: - drain_queue() - destroy_queue() 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. The series' patches: =================== Patch 1-2 Add the nvme-tcp-offload ULP module, including the APIs. Patches 3-5 nvme-tcp-offload ULP controller level functionalities. Patch 6 nvme-tcp-offload ULP queue level functionalities. Patch 7 nvme-tcp-offload ULP IO level functionalities. Patch 8 nvme-qedn Marvell's NVMeTCP HW offload vendor driver. Patch 9 net-qed NVMeTCP Offload PF level FW and HW HSI. Patch 10-11 nvme-qedn probe level functionalities. Performance: ============ With this implementation on top of the Marvell qedn driver (using the Marvell FastLinQ NIC), we were able to demonstrate x3 CPU utilization improvement for 4K queued read/write IOs and up to x20 in case of 512K read/write IOs. In addition, we were able to demonstrate latency improvement, and specifically 99.99% tail latency improvement of up to x2-5 (depends on the queue-depth). Future work: ============ For simplicity, the RFC series does not include the following functionalities which will be added based on the comments on patches 1-11. - nvme-tcp-offload teardown, IO timeout and async flows. - qedn device/queue/IO level. Long term future work: ============ - The nvme-tcp-offload ULP target abstraction layer. - The Marvell nvme-tcp-offload "qednt" target driver. Changes since RFC v1: ===================== - Fix nvme_tcp_ofld_ops return values. - Remove NVMF_TRTYPE_TCP_OFFLOAD. - Add nvme_tcp_ofld_poll() implementation. - Fix nvme_tcp_ofld_queue_rq() to check map_sg() and send_req() return values. Changes since RFC v2: ===================== - Add qedn - Marvell's NVMeTCP HW offload vendor driver init and probe (patches 8-11). - Fixes in controller and queue level (patches 3-6). Arie Gershberg (3): nvme-fabrics: Move NVMF_ALLOWED_OPTS and NVMF_REQUIRED_OPTS definitions nvme-tcp-offload: Add controller level implementation nvme-tcp-offload: Add controller level error recovery implementation Dean Balandin (3): nvme-tcp-offload: Add device scan implementation nvme-tcp-offload: Add queue level implementation nvme-tcp-offload: Add IO level implementation Shai Malin (5): nvme-tcp-offload: Add nvme-tcp-offload - NVMeTCP HW offload ULP nvme-qedn: Add qedn - Marvell's NVMeTCP HW offload vendor driver net-qed: Add NVMeTCP Offload PF Level FW and HW HSI nvme-qedn: Add qedn probe nvme-qedn: Add IRQ and fast-path resources initializations MAINTAINERS | 10 + drivers/net/ethernet/qlogic/Kconfig | 3 + drivers/net/ethernet/qlogic/qed/Makefile | 1 + drivers/net/ethernet/qlogic/qed/qed.h | 3 + drivers/net/ethernet/qlogic/qed/qed_hsi.h | 1 + drivers/net/ethernet/qlogic/qed/qed_nvmetcp.c | 269 ++++ drivers/net/ethernet/qlogic/qed/qed_nvmetcp.h | 48 + drivers/net/ethernet/qlogic/qed/qed_sp.h | 2 + drivers/nvme/Kconfig | 1 + drivers/nvme/Makefile | 1 + drivers/nvme/host/Kconfig | 16 + drivers/nvme/host/Makefile | 3 + drivers/nvme/host/fabrics.c | 7 - drivers/nvme/host/fabrics.h | 7 + drivers/nvme/host/tcp-offload.c | 1123 +++++++++++++++++ drivers/nvme/host/tcp-offload.h | 185 +++ drivers/nvme/hw/Kconfig | 9 + drivers/nvme/hw/Makefile | 3 + drivers/nvme/hw/qedn/Makefile | 3 + drivers/nvme/hw/qedn/qedn.c | 652 ++++++++++ drivers/nvme/hw/qedn/qedn.h | 90 ++ include/linux/qed/common_hsi.h | 1 + include/linux/qed/nvmetcp_common.h | 47 + include/linux/qed/qed_if.h | 22 + include/linux/qed/qed_nvmetcp_if.h | 71 ++ 25 files changed, 2571 insertions(+), 7 deletions(-) create mode 100644 drivers/net/ethernet/qlogic/qed/qed_nvmetcp.c create mode 100644 drivers/net/ethernet/qlogic/qed/qed_nvmetcp.h create mode 100644 drivers/nvme/host/tcp-offload.c create mode 100644 drivers/nvme/host/tcp-offload.h create mode 100644 drivers/nvme/hw/Kconfig create mode 100644 drivers/nvme/hw/Makefile create mode 100644 drivers/nvme/hw/qedn/Makefile create mode 100644 drivers/nvme/hw/qedn/qedn.c create mode 100644 drivers/nvme/hw/qedn/qedn.h create mode 100644 include/linux/qed/nvmetcp_common.h create mode 100644 include/linux/qed/qed_nvmetcp_if.h