1LIBPFM(3) Linux Programmer's Manual LIBPFM(3)
2
3
4
6 libpfm_intel_snbep_unc_pcu - support for Intel Sandy Bridge-EP Power
7 Controller Unit (PCU) uncore PMU
8
10 #include <perfmon/pfmlib.h>
11
12 PMU name: snbep_unc_pcu
13 PMU desc: Intel Sandy Bridge-EP PCU uncore PMU
14
15
17 The library supports the Intel Sandy Bridge Power Controller Unit
18 uncore PMU. This PMU model only exists on Sandy Bridge model 45. There
19 is only one PCU PMU per processor socket.
20
21
23 The following modifiers are supported on Intel Sandy Bridge C-Box
24 uncore PMU:
25
26 i Invert the meaning of the event. The counter will now count HA
27 cycles in which the event is not occurring. This is a boolean
28 modifier
29
30 e Enable edge detection, i.e., count only when there is a state
31 transition from no occurrence of the event to at least one
32 occurrence. This modifier must be combined with a threshold mod‐
33 ifier (t) with a value greater or equal to one. This is a bool‐
34 ean modifier.
35
36 t Set the threshold value. When set to a non-zero value, the
37 counter counts the number of HA cycles in which the number of
38 occurrences of the event is greater or equal to the threshold.
39 This is an integer modifier with values in the range [0:15].
40
41 ff Enable frequency band filtering. This modifier applies only to
42 the UNC_P_FREQ_BANDx_CYCLES events, where x is [0-3]. The modi‐
43 fiers expects an integer in the range [0-255]. The value is
44 interpreted as a frequency value to be multiplied by 100Mhz.
45 Thus if the value is 32, then all cycles where the processor is
46 running at 3.2GHz and more are counted.
47
48
50 There are 3 events which support frequency band filtering, namely,
51 UNC_P_FREQ_BAND0_CYCLES, UNC_P_FREQ_BAND1_CYCLES,
52 UNC_P_FREQ_BAND2_CYCLES, UNC_P_FREQ_BAND3_CYCLES. The frequency filter
53 (available via the ff modifier) is stored into a PMU shared register
54 which hold all 4 possible frequency bands, one per event. However, the
55 library generate the encoding for each event individually because it
56 processes events one at a time. The caller or the underlying kernel
57 interface may have to merge the band filter settings to program the
58 filter register properly.
59
60
62 Stephane Eranian <eranian@gmail.com>
63
64
65
66 August, 2012 LIBPFM(3)