From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 618CE19580A; Wed, 2 Oct 2024 21:35:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727904957; cv=none; b=A+Q5XCpce/A9RucUftugR336ZC4md0z9uh8Ltm/KTENTjTZzm8jcWj4OEsFjEasAVMEmWKsb7dVxX+wjLSItqn1Ktb8pAXZWrmER3n06TMwjGxtT07gblamcWDzz4LpCAi8hRQddy9uktYPsG0EoerAksRqaDMjrysmMHJGclYU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727904957; c=relaxed/simple; bh=BPbiYsLnxpgEFuYkCSBcKTHokotEyfQTGcEEcUl6TnA=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=kd+BCpABpp+/cxUfiny44XXBN4DZkkA1xngKu8/eCCv/hwWI6crL7rXh0F8ZfZksKPakD4KQliBkTZZX4Oz2HaZA1O/XY/tKGp2eUDWGirlsTC3/WfXkBDWtxxLZpN9vR1NHRFWXQ8zuS+kj76deMiUesB4H+wfKzXQsfhvOwgc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ky9rJ526; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ky9rJ526" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2A1DC4CEC2; Wed, 2 Oct 2024 21:35:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727904957; bh=BPbiYsLnxpgEFuYkCSBcKTHokotEyfQTGcEEcUl6TnA=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=Ky9rJ526vuWUEKhxy0ZbsYN1NC8eXxJWSPkxEq3lgZ5VFPwh9ptDnFGXCjSSBWZim tF1hXTuihLZi7+qszAKkwJFPylMnmPHtKNONBnJN+YA/+Zl6Uv3dTa8aPy6bJ8UTca KXKOUJePS0iO95Z1+bdkKeT4EYBa4TUpQtelox+v0BUouSfjdp4i8F3Tf6aOoSsWNS Uj3YvuFMHGEvvIknyHcOkFnbJ0Ldyg+74hbAKQeN2IaK8OCdgvd0g+MczuRmsShxli 0VIXbDVPzSXnn2QlpgGSFooAP/nRL98XmULO12jSj11ZtTxAPxDmgiOMtVmhO+QYRi COREpDs2yVytA== Date: Wed, 2 Oct 2024 16:35:55 -0500 From: Bjorn Helgaas To: Wei Huang Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, netdev@vger.kernel.org, Jonathan.Cameron@huawei.com, corbet@lwn.net, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, alex.williamson@redhat.com, gospo@broadcom.com, michael.chan@broadcom.com, ajit.khaparde@broadcom.com, somnath.kotur@broadcom.com, andrew.gospodarek@broadcom.com, manoj.panicker2@amd.com, Eric.VanTassell@amd.com, vadim.fedorenko@linux.dev, horms@kernel.org, bagasdotme@gmail.com, bhelgaas@google.com, lukas@wunner.de, paul.e.luse@intel.com, jing2.liu@intel.com Subject: Re: [PATCH V7 0/5] TPH and cache direct injection support Message-ID: <20241002213555.GA279877@bhelgaas> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241002165954.128085-1-wei.huang2@amd.com> On Wed, Oct 02, 2024 at 11:59:49AM -0500, Wei Huang wrote: > Hi All, > > TPH (TLP Processing Hints) is a PCIe feature that allows endpoint > devices to provide optimization hints for requests that target memory > space. These hints, in a format called steering tag (ST), are provided > in the requester's TLP headers and allow the system hardware, including > the Root Complex, to optimize the utilization of platform resources > for the requests. > > Upcoming AMD hardware implement a new Cache Injection feature that > leverages TPH. Cache Injection allows PCIe endpoints to inject I/O > Coherent DMA writes directly into an L2 within the CCX (core complex) > closest to the CPU core that will consume it. This technology is aimed > at applications requiring high performance and low latency, such as > networking and storage applications. > > This series introduces generic TPH support in Linux, allowing STs to be > retrieved and used by PCIe endpoint drivers as needed. As a > demonstration, it includes an example usage in the Broadcom BNXT driver. > When running on Broadcom NICs with the appropriate firmware, it shows > substantial memory bandwidth savings and better network bandwidth using > real-world benchmarks. This solution is vendor-neutral and implemented > based on industry standards (PCIe Spec and PCI FW Spec). > > V6->V7: > * Rebase on top of the latest pci/main (6.12-rc1) > * Fix compilation warning/error on clang-18 with w=1 (test robot) > * Revise commit messages for Patch #2, #4, and #5 (Bjorn) > * Add more _DSM method description for reference in Patch #2 (Bjorn) > * Remove "default n" in Kconfig (Lukas) > > V5->V6: > * Rebase on top of pci/main (tag: pci-v6.12-changes) > * Fix spellings and FIELD_PREP/bnxt.c compilation errors (Simon) > * Move tph.c to drivers/pci directory (Lukas) > * Remove CONFIG_ACPI dependency (Lukas) > * Slightly re-arrange save/restore sequence (Lukas) > > V4->V5: > * Rebase on top of net-next/main tree (Broadcom) > * Remove TPH mode query and TPH enabled checking functions (Bjorn) > * Remove "nostmode" kernel parameter (Bjorn) > * Add "notph" kernel parameter support (Bjorn) > * Add back TPH documentation (Bjorn) > * Change TPH register namings (Bjorn) > * Squash TPH enable/disable/save/restore funcs as a single patch (Bjorn) > * Squash ST get_st/set_st funcs as a single patch (Bjorn) > * Replace nic_open/close with netdev_rx_queue_restart() (Jakub, Broadcom) > > V3->V4: > * Rebase on top of the latest pci/next tree (tag: 6.11-rc1) > * Add new API functioins to query/enable/disable TPH support > * Make pcie_tph_set_st() completely independent from pcie_tph_get_cpu_st() > * Rewrite bnxt.c based on new APIs > * Remove documentation for now due to constantly changing API > * Remove pci=notph, but keep pci=nostmode with better flow (Bjorn) > * Lots of code rewrite in tph.c & pci-tph.h with cleaner interface (Bjorn) > * Add TPH save/restore support (Paul Luse and Lukas Wunner) > > V2->V3: > * Rebase on top of pci/next tree (tag: pci-v6.11-changes) > * Redefine PCI TPH registers (pci_regs.h) without breaking uapi > * Fix commit subjects/messages for kernel options (Jonathan and Bjorn) > * Break API functions into three individual patches for easy review > * Rewrite lots of code in tph.c/tph.h based (Jonathan and Bjorn) > > V1->V2: > * Rebase on top of pci.git/for-linus (6.10-rc1) > * Address mismatched data types reported by Sparse (Sparse check passed) > * Add pcie_tph_intr_vec_supported() for checking IRQ mode support > * Skip bnxt affinity notifier registration if > pcie_tph_intr_vec_supported()=false > * Minor fixes in bnxt driver (i.e. warning messages) > > Manoj Panicker (1): > bnxt_en: Add TPH support in BNXT driver > > Michael Chan (1): > bnxt_en: Pass NQ ID to the FW when allocating RX/RX AGG rings > > Wei Huang (3): > PCI: Add TLP Processing Hints (TPH) support > PCI/TPH: Add Steering Tag support > PCI/TPH: Add TPH documentation > > Documentation/PCI/index.rst | 1 + > Documentation/PCI/tph.rst | 132 +++++ > .../admin-guide/kernel-parameters.txt | 4 + > Documentation/driver-api/pci/pci.rst | 3 + > drivers/net/ethernet/broadcom/bnxt/bnxt.c | 91 ++- > drivers/net/ethernet/broadcom/bnxt/bnxt.h | 7 + > drivers/pci/Kconfig | 9 + > drivers/pci/Makefile | 1 + > drivers/pci/pci.c | 4 + > drivers/pci/pci.h | 12 + > drivers/pci/probe.c | 1 + > drivers/pci/tph.c | 546 ++++++++++++++++++ > include/linux/pci-tph.h | 44 ++ > include/linux/pci.h | 7 + > include/uapi/linux/pci_regs.h | 37 +- > net/core/netdev_rx_queue.c | 1 + > 16 files changed, 890 insertions(+), 10 deletions(-) > create mode 100644 Documentation/PCI/tph.rst > create mode 100644 drivers/pci/tph.c > create mode 100644 include/linux/pci-tph.h I tentatively applied this on pci/tph for v6.13. Not sure what you intend for the bnxt changes, since they depend on the PCI core changes. I'm happy to merge them via PCI, given acks from Michael and an overall network maintainer. Alternatively they could wait another cycle, or I could make an immutable branch, although I prefer to preserve the option to update or remove things until the merge window. Thanks very much; this looks like nice work! Bjorn