1LIBPFM(3) Linux Programmer's Manual LIBPFM(3)
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6 libpfm_intel_icl - support for Intel IceLake core PMU
7
9 #include <perfmon/pfmlib.h>
10 PMU name: icl
12 PMU desc: Intel IceLake
13
16 The library supports the Intel IceLake core PMU. It should be noted
17 that this PMU model only covers each core's PMU and not the socket
18 level PMU.
19 On IceLake, the number of generic counters depends on the Hyperthread‐
21 ing (HT) mode.
22 The pfm_get_pmu_info() function returns the maximum number of generic
24 counters in num_cntrs.
25
28 The following modifiers are supported on Intel IceLake processors:
29 u Measure at user level which includes privilege levels 1, 2, 3.
31 This corresponds to PFM_PLM3. This is a boolean modifier.
32 k Measure at kernel level which includes privilege level 0. This
34 corresponds to PFM_PLM0. This is a boolean modifier.
35 i Invert the meaning of the event. The counter will now count cy‐
37 cles in which the event is not occurring. This is a boolean mod‐
38 ifier
39 e Enable edge detection, i.e., count only when there is a state
41 transition from no occurrence of the event to at least one oc‐
42 currence. This modifier must be combined with a counter mask
43 modifier (m) with a value greater or equal to one. This is a
44 boolean modifier.
45 c Set the counter mask value. The mask acts as a threshold. The
47 counter will count the number of cycles in which the number of
48 occurrences of the event is greater or equal to the threshold.
49 This is an integer modifier with values in the range [0:255].
50 ldlat Pass a latency threshold to the MEM_TRANS_RETIRED:LOAD_LATENCY
52 event. This is an integer attribute that must be in the range
53 [3:65535]. It is required for this event. Note that the event
54 must be used with precise sampling (PEBS).
55 intx Monitor the event only when executing inside a transactional
57 memory region (in tx). Event does not count otherwise. This is a
58 boolean modifiers. Default value is 0.
59 intxcp Do not count occurrences of the event when they are inside an
61 aborted transactional memory region. This is a boolean modifier.
62 Default value is 0.
63 fe_thres
65 This modifier is for the FRONTEND_RETIRED event only. It defines
66 the period in core cycles after which the IDQ_*_BUBBLES umask
67 counts. It acts as a threshold, i.e., at least a period of N
68 core cycles where the frontend did not deliver X uops. It can
69 only be used with the IDQ_*_BUBBLES umasks. If not specified,
70 the default threshold value is 1 cycle. the valid values are in
71 [1-4095].
72
75 Intel IceLake supports two encodings for offcore_response events. In
76 the library, these are called OFFCORE_RESPONSE_0 and OFFCORE_RE‐
77 SPONSE_1.
78 Those events need special treatment in the performance monitoring in‐
80 frastructure because each event uses an extra register to store some
81 settings. Thus, in case multiple offcore_response events are monitored
82 simultaneously, the operating system needs to manage the sharing of
83 that extra register.
84 The offcore_response events are exposed as a normal events by the li‐
86 brary. The extra settings are exposed as regular umasks. The library
87 takes care of encoding the events according to the underlying kernel
88 interface.
89 On Intel IceLake unlike older processors, the event is treated as a
91 regular event with a flat set of umasks to choose from. It is not pos‐
92 sible to combine the various requests, supplier, snoop bits anymore.
93 Therefore the library offers the list of validated combinations as per
94 Intel's official event list.
95
98 Stephane Eranian <eranian@gmail.com>
99 August, 2015 LIBPFM(3)