1 .. SPDX-License-Identifier: GPL-2.0
2
3 ======================================
4 CXL Performance Monitoring Unit (CPMU)
5 ======================================
6
7 The CXL rev 3.0 specification provides a defin
8 Monitoring Unit in section 13.2: Performance M
9
10 CXL components (e.g. Root Port, Switch Upstrea
11 any number of CPMU instances. CPMU capabilitie
12 the devices. The specification provides event
13 message types and a set of additional events f
14 CXL devices (e.g. DRAM events).
15
16 CPMU driver
17 ===========
18
19 The CPMU driver registers a perf PMU with the
20 representing the Yth CPMU for memX.
21
22 /sys/bus/cxl/device/pmu_mem<X>.<Y>
23
24 The associated PMU is registered as
25
26 /sys/bus/event_sources/devices/cxl_pmu_mem<
27
28 In common with other CXL bus devices, the id h
29 relationship to specific CXL device should be
30 of the device on the CXL bus.
31
32 PMU driver provides description of available e
33
34 The "format" directory describes all formats o
35 group id and mask) config1 (threshold, filter
36 parameters) fields of the perf_event_attr stru
37 describes all documented events show in perf l
38
39 The events shown in perf list are the most fin
40 bit of the event mask set. More general events
41 multiple mask bits in config. For example, all
42 may be captured on a single counter by setting
43
44 * d2h_req_rdcurr
45 * d2h_req_rdown
46 * d2h_req_rdshared
47 * d2h_req_rdany
48 * d2h_req_rdownnodata
49
50 Example of usage::
51
52 $#perf list
53 cxl_pmu_mem0.0/clock_ticks/
54 cxl_pmu_mem0.0/d2h_req_rdshared/
55 cxl_pmu_mem0.0/h2d_req_snpcur/
56 cxl_pmu_mem0.0/h2d_req_snpdata/
57 cxl_pmu_mem0.0/h2d_req_snpinv/
58 --------------------------------------------
59
60 $# perf stat -a -e cxl_pmu_mem0.0/clock_tick
61
62 Vendor specific events may also be available a
63
64 $# perf stat -a -e cxl_pmu_mem0.0/vid=VID,gi
65
66 The driver does not support sampling so "perf
67 It only supports system-wide counting so attac
68 unsupported.
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