From 5d7107c72796df3be2ba574f1cf6eca75c60d5ef Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Fri, 26 May 2023 10:58:23 +0100 Subject: perf: CXL Performance Monitoring Unit driver CXL rev 3.0 introduces a standard performance monitoring hardware block to CXL. Instances are discovered using CXL Register Locator DVSEC entries. Each CXL component may have multiple PMUs. This initial driver supports a subset of types of counter. It supports counters that are either fixed or configurable, but requires that they support the ability to freeze and write value whilst frozen. Development done with QEMU model which will be posted shortly. Example: $ perf stat -a -e cxl_pmu_mem0.0/h2d_req_snpcur/ -e cxl_pmu_mem0.0/h2d_req_snpdata/ -e cxl_pmu_mem0.0/clock_ticks/ sleep 1 Performance counter stats for 'system wide': 96,757,023,244,321 cxl_pmu_mem0.0/h2d_req_snpcur/ 96,757,023,244,365 cxl_pmu_mem0.0/h2d_req_snpdata/ 193,514,046,488,653 cxl_pmu_mem0.0/clock_ticks/ 1.090539600 seconds time elapsed Reviewed-by: Dave Jiang Reviewed-by: Kan Liang Signed-off-by: Jonathan Cameron Link: https://lore.kernel.org/r/20230526095824.16336-5-Jonathan.Cameron@huawei.com Signed-off-by: Dan Williams --- MAINTAINERS | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 250518fc70ff..e0ede1ed1361 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5193,6 +5193,12 @@ S: Maintained F: drivers/cxl/ F: include/uapi/linux/cxl_mem.h +COMPUTE EXPRESS LINK PMU (CPMU) +M: Jonathan Cameron +L: linux-cxl@vger.kernel.org +S: Maintained +F: drivers/perf/cxl_pmu.c + CONEXANT ACCESSRUNNER USB DRIVER L: accessrunner-general@lists.sourceforge.net S: Orphan -- cgit v1.2.3 From c2b34d442226b69e519eb0ba61939a74d91712d4 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Fri, 26 May 2023 10:58:24 +0100 Subject: docs: perf: Minimal introduction the the CXL PMU device and driver Very basic introduction to the device and the current driver support provided. I expect to expand on this in future versions of this patch set. Reviewed-by: Dave Jiang Reviewed-by: Kan Liang Signed-off-by: Jonathan Cameron Link: https://lore.kernel.org/r/20230526095824.16336-6-Jonathan.Cameron@huawei.com Signed-off-by: Dan Williams --- Documentation/admin-guide/perf/cxl.rst | 68 ++++++++++++++++++++++++++++++++ Documentation/admin-guide/perf/index.rst | 1 + MAINTAINERS | 1 + 3 files changed, 70 insertions(+) create mode 100644 Documentation/admin-guide/perf/cxl.rst (limited to 'MAINTAINERS') diff --git a/Documentation/admin-guide/perf/cxl.rst b/Documentation/admin-guide/perf/cxl.rst new file mode 100644 index 000000000000..9233ea0d0b10 --- /dev/null +++ b/Documentation/admin-guide/perf/cxl.rst @@ -0,0 +1,68 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================== +CXL Performance Monitoring Unit (CPMU) +====================================== + +The CXL rev 3.0 specification provides a definition of CXL Performance +Monitoring Unit in section 13.2: Performance Monitoring. + +CXL components (e.g. Root Port, Switch Upstream Port, End Point) may have +any number of CPMU instances. CPMU capabilities are fully discoverable from +the devices. The specification provides event definitions for all CXL protocol +message types and a set of additional events for things commonly counted on +CXL devices (e.g. DRAM events). + +CPMU driver +=========== + +The CPMU driver registers a perf PMU with the name pmu_mem. on the CXL bus +representing the Yth CPMU for memX. + + /sys/bus/cxl/device/pmu_mem. + +The associated PMU is registered as + + /sys/bus/event_sources/devices/cxl_pmu_mem. + +In common with other CXL bus devices, the id has no specific meaning and the +relationship to specific CXL device should be established via the device parent +of the device on the CXL bus. + +PMU driver provides description of available events and filter options in sysfs. + +The "format" directory describes all formats of the config (event vendor id, +group id and mask) config1 (threshold, filter enables) and config2 (filter +parameters) fields of the perf_event_attr structure. The "events" directory +describes all documented events show in perf list. + +The events shown in perf list are the most fine grained events with a single +bit of the event mask set. More general events may be enable by setting +multiple mask bits in config. For example, all Device to Host Read Requests +may be captured on a single counter by setting the bits for all of + +* d2h_req_rdcurr +* d2h_req_rdown +* d2h_req_rdshared +* d2h_req_rdany +* d2h_req_rdownnodata + +Example of usage:: + + $#perf list + cxl_pmu_mem0.0/clock_ticks/ [Kernel PMU event] + cxl_pmu_mem0.0/d2h_req_rdshared/ [Kernel PMU event] + cxl_pmu_mem0.0/h2d_req_snpcur/ [Kernel PMU event] + cxl_pmu_mem0.0/h2d_req_snpdata/ [Kernel PMU event] + cxl_pmu_mem0.0/h2d_req_snpinv/ [Kernel PMU event] + ----------------------------------------------------------- + + $# perf stat -a -e cxl_pmu_mem0.0/clock_ticks/ -e cxl_pmu_mem0.0/d2h_req_rdshared/ + +Vendor specific events may also be available and if so can be used via + + $# perf stat -a -e cxl_pmu_mem0.0/vid=VID,gid=GID,mask=MASK/ + +The driver does not support sampling so "perf record" is unsupported. +It only supports system-wide counting so attaching to a task is +unsupported. diff --git a/Documentation/admin-guide/perf/index.rst b/Documentation/admin-guide/perf/index.rst index 9de64a40adab..f60be04e4e33 100644 --- a/Documentation/admin-guide/perf/index.rst +++ b/Documentation/admin-guide/perf/index.rst @@ -21,3 +21,4 @@ Performance monitor support alibaba_pmu nvidia-pmu meson-ddr-pmu + cxl diff --git a/MAINTAINERS b/MAINTAINERS index e0ede1ed1361..aefb5ef084be 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5197,6 +5197,7 @@ COMPUTE EXPRESS LINK PMU (CPMU) M: Jonathan Cameron L: linux-cxl@vger.kernel.org S: Maintained +F: Documentation/admin-guide/perf/cxl.rst F: drivers/perf/cxl_pmu.c CONEXANT ACCESSRUNNER USB DRIVER -- cgit v1.2.3