From patchwork Tue Apr 11 18:54:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 13208084 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97EBAC76196 for ; Tue, 11 Apr 2023 18:54:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229458AbjDKSy6 (ORCPT ); Tue, 11 Apr 2023 14:54:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229486AbjDKSy5 (ORCPT ); Tue, 11 Apr 2023 14:54:57 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5836C10E3; Tue, 11 Apr 2023 11:54:53 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Pww272BFVz6J6Yn; Wed, 12 Apr 2023 02:52:31 +0800 (CST) Received: from SecurePC-101-06.china.huawei.com (10.122.247.231) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Tue, 11 Apr 2023 19:54:50 +0100 From: Jonathan Cameron To: Liang Kan , , , , CC: , , , , , , Davidlohr Bueso , Dave Jiang Subject: [PATCH v5 0/5] perf: CXL 3.0 Performance Monitoring Unit support Date: Tue, 11 Apr 2023 19:54:47 +0100 Message-ID: <20230411185452.23387-1-Jonathan.Cameron@huawei.com> X-Mailer: git-send-email 2.37.2 MIME-Version: 1.0 X-Originating-IP: [10.122.247.231] X-ClientProxiedBy: lhrpeml500001.china.huawei.com (7.191.163.213) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org Was CXL 3.0 Performance Monitoring Unit support. Renamed to highlight the driver has moved to drivers/perf Dan Williams has expressed that he is happy to take this through the CXL tree once perf reviewers are happy with those parts. Thanks to Kan and Dan for reviews. Major changes since v4: (Smaller changes described in individual patches) - Move driver from drivers/cxl/cpmu.c to drivers/perf/cxl_pmu.c - Rename devices to associate with cxl/devices/memX etc. Scheme extends to CPMU instances on Upstream and Downstream CXL ports. - Rename CXL core files to simply pmu.* and simplify code structure naming and similar to cxl_pmu* CXL_PMU* etc Patch 1/5 is also present in the series: [PATCH 00/32] Add parents to struct pmu -> dev which may merge first. Update introduction. The CXL rev 3.0 specification introduces a CXL Performance Monitoring Unit definition. CXL components may have any number of these blocks. The definition is highly flexible, but that does bring complexity in the driver. All instances are self describing, though for vendor defined events we expect mapping from numeric values to counter names to be performed in userspace tooling. In common with many CXL features, this driver precedes any announced hardware (that I'm aware of anyway!). Supported features are: - Devices that allow counters to be written when frozen (allows a single register write to start / stop all counters). - Fixed purpose counters - Configurable counters - CXL specification defined events + HDM filters. This initial series covers a useful subset of functionality and is expected to be followed by patch series addressing: * Discoverability beyond fine grained events. This will cover both vendor defined events and providing perf tool with the visibility to be able construct 'summed' events. For example if a single counter can cover all host to device read traffic. Perf tool patches will use this information and appropriate schema to present a richer set of countable events. * CXL PMU instances on Upstream and Downstream CXL switch ports and root ports. * Free running counters. Often used for vendor defined debug type events and error counters. Likely to appear on real devices. * Devices without interrupt support for overflow. * Devices that don't support freeze (counters need to be enabled individually). Exact priority order for the above features will depend on early hardware though (a) will definitely be top of the list as any likely hardware will be able to take advantage of that feature. Notes. 1) The QEMU model against which this was developed needs tidying up. Latest tree at https://gitlab.com/jic23/qemu branch cxl-2023-02-28 It's backed up behind other series that I plan to upstream first. 2) V1 led to a discussion of how to handle the self describing and extensible nature of the CPMU counters. That is likely to involve a description in the "caps" sysfs directory and perf tool code that is aware of the different event combinations that make sense and can establish which sets are available on a given device. That is likely to take a while to converge on, so as the driver is useful in the current state, I'm looking to upstream this first and deal with the more complex handling later. 3) There is a lot of other functionality that can be added in future include allowing for simpler hardware implementations that may not support the minimum level of features currently required by the driver (freeze, overflow interrupts etc). 4) Adding support for ports will require solving msi/msix vector requests from portdrv and how to pass those to the CXL port drivers. (or some other way to instantiate the CXL PMU devices.) RFC on that to follow. CXL rev 3.0 specification available from https://www.computeexpresslink.org Jonathan Cameron (5): perf: Allow a PMU to have a parent cxl: Add functions to get an instance of / count regblocks of a given type cxl/pci: Find and register CXL PMU devices perf: CXL Performance Monitoring Unit driver docs: perf: Minimal introduction the the CXL PMU device and driver Documentation/admin-guide/perf/cxl.rst | 68 ++ Documentation/admin-guide/perf/index.rst | 1 + MAINTAINERS | 7 + drivers/cxl/Kconfig | 13 + drivers/cxl/core/Makefile | 1 + drivers/cxl/core/core.h | 1 + drivers/cxl/core/pmu.c | 69 ++ drivers/cxl/core/port.c | 2 + drivers/cxl/core/regs.c | 75 +- drivers/cxl/cxl.h | 16 + drivers/cxl/cxlpci.h | 1 + drivers/cxl/pci.c | 26 +- drivers/cxl/pmu.h | 28 + drivers/perf/Kconfig | 13 + drivers/perf/Makefile | 1 + drivers/perf/cxl_pmu.c | 984 +++++++++++++++++++++++ include/linux/perf_event.h | 1 + kernel/events/core.c | 1 + 18 files changed, 1301 insertions(+), 7 deletions(-) create mode 100644 Documentation/admin-guide/perf/cxl.rst create mode 100644 drivers/cxl/core/pmu.c create mode 100644 drivers/cxl/pmu.h create mode 100644 drivers/perf/cxl_pmu.c