1 ==========================
2 ARM Cache Coherent Network
3 ==========================
4
5 CCN-504 is a ring-bus interconnect consisting
6 (XPs), with each crosspoint supporting up to t
7 so nodes (devices) 0 and 1 are connected to cr
8 nodes 2 and 3 to crosspoint 1 etc.
9
10 PMU (perf) driver
11 -----------------
12
13 The CCN driver registers a perf PMU driver, wh
14 description of available events and configurat
15 in sysfs, see /sys/bus/event_source/devices/cc
16
17 The "format" directory describes format of the
18 and config2 fields of the perf_event_attr stru
19 directory provides configuration templates for
20 events, that can be used with perf tool. For e
21 is an equivalent of "type=0x8,event=0x4". Othe
22 explicitly specified.
23
24 For events originating from device, "node" def
25
26 Crosspoint PMU events require "xp" (index), "b
27 and "vc" (virtual channel ID).
28
29 Crosspoint watchpoint-based events (special "e
30 require "xp" and "vc" as above plus "port" (de
31 "dir" (transmit/receive direction), comparator
32 and "cmp_h") and "mask", being index of the co
33
34 Masks are defined separately from the event de
35 (due to limited number of the config values) i
36 directory, with first 8 configurable by user a
37 4 hardcoded for the most frequent use cases.
38
39 Cycle counter is described by a "type" value 0
40 not require any other settings.
41
42 The driver also provides a "cpumask" sysfs att
43 a single CPU ID, of the processor which will b
44 the CCN PMU events. It is recommended that the
45 request the events on this processor (if not,
46 will be overwritten anyway). In case of this p
47 the events are migrated to another one and the
48
49 Example of perf tool use::
50
51 / # perf list | grep ccn
52 ccn/cycles/
53 <...>
54 ccn/xp_valid_flit,xp=?,port=?,vc=?,dir=?/
55 <...>
56
57 / # perf stat -a -e ccn/cycles/,ccn/xp_valid
58
59
60 The driver does not support sampling, therefor
61 not work. Per-task (without "-a") perf session
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