1LIBPFM(3) Linux Programmer's Manual LIBPFM(3)
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6 libpfm_intel_ivb - support for Intel Ivy Bridge core PMU
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9 #include <perfmon/pfmlib.h>
10 PMU name: ivb
12 PMU desc: Intel Ivy Bridge
13 PMU name: ivb_ep
14 PMU desc: Intel Ivy Bridge EP
15
18 The library supports the Intel Ivy Bridge core PMU. It should be noted
19 that this PMU model only covers each core's PMU and not the socket
20 level PMU.
21 On Ivy Bridge, the number of generic counters depends on the Hyper‐
23 threading (HT) mode. When HT is on, then only 4 generic counters are
24 available. When HT is off, then 8 generic counters are available. The
25 pfm_get_pmu_info() function returns the maximum number of generic coun‐
26 ters in num_cntrs.
27
30 The following modifiers are supported on Intel Ivy Bridge processors:
31 u Measure at user level which includes privilege levels 1, 2, 3.
33 This corresponds to PFM_PLM3. This is a boolean modifier.
34 k Measure at kernel level which includes privilege level 0. This
36 corresponds to PFM_PLM0. This is a boolean modifier.
37 i Invert the meaning of the event. The counter will now count cy‐
39 cles in which the event is not occurring. This is a boolean mod‐
40 ifier
41 e Enable edge detection, i.e., count only when there is a state
43 transition from no occurrence of the event to at least one oc‐
44 currence. This modifier must be combined with a counter mask
45 modifier (m) with a value greater or equal to one. This is a
46 boolean modifier.
47 c Set the counter mask value. The mask acts as a threshold. The
49 counter will count the number of cycles in which the number of
50 occurrences of the event is greater or equal to the threshold.
51 This is an integer modifier with values in the range [0:255].
52 t Measure on both threads at the same time assuming hyper-thread‐
54 ing is enabled. This is a boolean modifier.
55 ldlat Pass a latency threshold to the MEM_TRANS_RETIRED:LA‐
57 TENCY_ABOVE_THRESHOLD event. This is an integer attribute that
58 must be in the range [1:65535]. It is required for this event.
59 Note that the event must be used with precise sampling (PEBS).
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63 Intel Ivy Bridge provides two offcore_response events. They are called
64 OFFCORE_RESPONSE_0 and OFFCORE_RESPONSE_1.
65 Those events need special treatment in the performance monitoring in‐
67 frastructure because each event uses an extra register to store some
68 settings. Thus, in case multiple offcore_response events are monitored
69 simultaneously, the kernel needs to manage the sharing of that extra
70 register.
71 The offcore_response events are exposed as a normal events by the li‐
73 brary. The extra settings are exposed as regular umasks. The library
74 takes care of encoding the events according to the underlying kernel
75 interface.
76 On Intel Ivy Bridge, the umasks are divided into three categories: re‐
78 quest, supplier and snoop. The user must provide at least one umask for
79 each category. The categories are shown in the umask descriptions.
80 There is also the special response umask called ANY_RESPONSE. When this
82 umask is used then it overrides any supplier and snoop umasks. In other
83 words, users can specify either ANY_RESPONSE OR any combinations of
84 supplier + snoops.
85 In case no supplier or snoop is specified, the library defaults to us‐
87 ing ANY_RESPONSE.
88 For instance, the following are valid event selections:
90 OFFCORE_RESPONSE_0:DMND_DATA_RD:ANY_RESPONSE
92 OFFCORE_RESPONSE_0:ANY_REQUEST
94 OFFCORE_RESPONSE_0:ANY_RFO:LLC_HITM:SNOOP_ANY
96 But the following are illegal:
99 OFFCORE_RESPONSE_0:ANY_RFO:LLC_HITM:ANY_RESPONSE
102 OFFCORE_RESPONSE_0:ANY_RFO:LLC_HITM:SNOOP_ANY:ANY_RESPONSE
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107 Stephane Eranian <eranian@gmail.com>
108 August, 2012 LIBPFM(3)