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386b05e3 | 1 | perf-list(1) |
6e6b754f | 2 | ============ |
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3 | |
4 | NAME | |
5 | ---- | |
6 | perf-list - List all symbolic event types | |
7 | ||
8 | SYNOPSIS | |
9 | -------- | |
10 | [verse] | |
dc098b35 | 11 | 'perf list' [hw|sw|cache|tracepoint|pmu|event_glob] |
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12 | |
13 | DESCRIPTION | |
14 | ----------- | |
15 | This command displays the symbolic event types which can be selected in the | |
16 | various perf commands with the -e option. | |
17 | ||
75bc5ca8 | 18 | [[EVENT_MODIFIERS]] |
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19 | EVENT MODIFIERS |
20 | --------------- | |
21 | ||
96355f2c | 22 | Events can optionally have a modifier by appending a colon and one or |
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23 | more modifiers. Modifiers allow the user to restrict the events to be |
24 | counted. The following modifiers exist: | |
25 | ||
26 | u - user-space counting | |
27 | k - kernel counting | |
28 | h - hypervisor counting | |
a1e12da4 | 29 | I - non idle counting |
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30 | G - guest counting (in KVM guests) |
31 | H - host counting (not in KVM guests) | |
32 | p - precise level | |
7f94af7a | 33 | P - use maximum detected precise level |
3c176311 | 34 | S - read sample value (PERF_SAMPLE_READ) |
e9a7c414 | 35 | D - pin the event to the PMU |
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36 | |
37 | The 'p' modifier can be used for specifying how precise the instruction | |
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38 | address should be. The 'p' modifier can be specified multiple times: |
39 | ||
40 | 0 - SAMPLE_IP can have arbitrary skid | |
41 | 1 - SAMPLE_IP must have constant skid | |
42 | 2 - SAMPLE_IP requested to have 0 skid | |
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43 | 3 - SAMPLE_IP must have 0 skid, or uses randomization to avoid |
44 | sample shadowing effects. | |
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45 | |
46 | For Intel systems precise event sampling is implemented with PEBS | |
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47 | which supports up to precise-level 2, and precise level 3 for |
48 | some special cases | |
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49 | |
50 | On AMD systems it is implemented using IBS (up to precise-level 2). | |
51 | The precise modifier works with event types 0x76 (cpu-cycles, CPU | |
52 | clocks not halted) and 0xC1 (micro-ops retired). Both events map to | |
53 | IBS execution sampling (IBS op) with the IBS Op Counter Control bit | |
54 | (IbsOpCntCtl) set respectively (see AMD64 Architecture Programmer’s | |
55 | Manual Volume 2: System Programming, 13.3 Instruction-Based | |
56 | Sampling). Examples to use IBS: | |
ffec5169 | 57 | |
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58 | perf record -a -e cpu-cycles:p ... # use ibs op counting cycles |
59 | perf record -a -e r076:p ... # same as -e cpu-cycles:p | |
60 | perf record -a -e r0C1:p ... # use ibs op counting micro-ops | |
ffec5169 | 61 | |
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62 | RAW HARDWARE EVENT DESCRIPTOR |
63 | ----------------------------- | |
64 | Even when an event is not available in a symbolic form within perf right now, | |
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65 | it can be encoded in a per processor specific way. |
66 | ||
67 | For instance For x86 CPUs NNN represents the raw register encoding with the | |
68 | layout of IA32_PERFEVTSELx MSRs (see [Intel® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide] Figure 30-1 Layout | |
69 | of IA32_PERFEVTSELx MSRs) or AMD's PerfEvtSeln (see [AMD64 Architecture Programmer’s Manual Volume 2: System Programming], Page 344, | |
70 | Figure 13-7 Performance Event-Select Register (PerfEvtSeln)). | |
71 | ||
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72 | Note: Only the following bit fields can be set in x86 counter |
73 | registers: event, umask, edge, inv, cmask. Esp. guest/host only and | |
74 | OS/user mode flags must be setup using <<EVENT_MODIFIERS, EVENT | |
75 | MODIFIERS>>. | |
76 | ||
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77 | Example: |
78 | ||
79 | If the Intel docs for a QM720 Core i7 describe an event as: | |
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80 | |
81 | Event Umask Event Mask | |
82 | Num. Value Mnemonic Description Comment | |
83 | ||
84 | A8H 01H LSD.UOPS Counts the number of micro-ops Use cmask=1 and | |
85 | delivered by loop stream detector invert to count | |
86 | cycles | |
87 | ||
88 | raw encoding of 0x1A8 can be used: | |
89 | ||
90 | perf stat -e r1a8 -a sleep 1 | |
91 | perf record -e r1a8 ... | |
92 | ||
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93 | You should refer to the processor specific documentation for getting these |
94 | details. Some of them are referenced in the SEE ALSO section below. | |
95 | ||
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96 | ARBITRARY PMUS |
97 | -------------- | |
98 | ||
99 | perf also supports an extended syntax for specifying raw parameters | |
100 | to PMUs. Using this typically requires looking up the specific event | |
101 | in the CPU vendor specific documentation. | |
102 | ||
103 | The available PMUs and their raw parameters can be listed with | |
104 | ||
105 | ls /sys/devices/*/format | |
106 | ||
107 | For example the raw event "LSD.UOPS" core pmu event above could | |
108 | be specified as | |
109 | ||
110 | perf stat -e cpu/event=0xa8,umask=0x1,name=LSD.UOPS_CYCLES,cmask=1/ ... | |
111 | ||
112 | PER SOCKET PMUS | |
113 | --------------- | |
114 | ||
115 | Some PMUs are not associated with a core, but with a whole CPU socket. | |
116 | Events on these PMUs generally cannot be sampled, but only counted globally | |
117 | with perf stat -a. They can be bound to one logical CPU, but will measure | |
118 | all the CPUs in the same socket. | |
119 | ||
120 | This example measures memory bandwidth every second | |
121 | on the first memory controller on socket 0 of a Intel Xeon system | |
122 | ||
123 | perf stat -C 0 -a uncore_imc_0/cas_count_read/,uncore_imc_0/cas_count_write/ -I 1000 ... | |
124 | ||
125 | Each memory controller has its own PMU. Measuring the complete system | |
126 | bandwidth would require specifying all imc PMUs (see perf list output), | |
127 | and adding the values together. | |
128 | ||
129 | This example measures the combined core power every second | |
130 | ||
131 | perf stat -I 1000 -e power/energy-cores/ -a | |
132 | ||
133 | ACCESS RESTRICTIONS | |
134 | ------------------- | |
135 | ||
136 | For non root users generally only context switched PMU events are available. | |
137 | This is normally only the events in the cpu PMU, the predefined events | |
138 | like cycles and instructions and some software events. | |
139 | ||
140 | Other PMUs and global measurements are normally root only. | |
141 | Some event qualifiers, such as "any", are also root only. | |
142 | ||
143 | This can be overriden by setting the kernel.perf_event_paranoid | |
144 | sysctl to -1, which allows non root to use these events. | |
145 | ||
146 | For accessing trace point events perf needs to have read access to | |
147 | /sys/kernel/debug/tracing, even when perf_event_paranoid is in a relaxed | |
148 | setting. | |
149 | ||
150 | TRACING | |
151 | ------- | |
152 | ||
153 | Some PMUs control advanced hardware tracing capabilities, such as Intel PT, | |
154 | that allows low overhead execution tracing. These are described in a separate | |
155 | intel-pt.txt document. | |
156 | ||
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157 | PARAMETERIZED EVENTS |
158 | -------------------- | |
159 | ||
160 | Some pmu events listed by 'perf-list' will be displayed with '?' in them. For | |
161 | example: | |
162 | ||
163 | hv_gpci/dtbp_ptitc,phys_processor_idx=?/ | |
164 | ||
165 | This means that when provided as an event, a value for '?' must | |
166 | also be supplied. For example: | |
167 | ||
168 | perf stat -C 0 -e 'hv_gpci/dtbp_ptitc,phys_processor_idx=0x2/' ... | |
169 | ||
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170 | EVENT GROUPS |
171 | ------------ | |
172 | ||
173 | Perf supports time based multiplexing of events, when the number of events | |
174 | active exceeds the number of hardware performance counters. Multiplexing | |
175 | can cause measurement errors when the workload changes its execution | |
176 | profile. | |
177 | ||
178 | When metrics are computed using formulas from event counts, it is useful to | |
179 | ensure some events are always measured together as a group to minimize multiplexing | |
180 | errors. Event groups can be specified using { }. | |
181 | ||
182 | perf stat -e '{instructions,cycles}' ... | |
183 | ||
184 | The number of available performance counters depend on the CPU. A group | |
185 | cannot contain more events than available counters. | |
186 | For example Intel Core CPUs typically have four generic performance counters | |
187 | for the core, plus three fixed counters for instructions, cycles and | |
188 | ref-cycles. Some special events have restrictions on which counter they | |
189 | can schedule, and may not support multiple instances in a single group. | |
190 | When too many events are specified in the group none of them will not | |
191 | be measured. | |
192 | ||
193 | Globally pinned events can limit the number of counters available for | |
194 | other groups. On x86 systems, the NMI watchdog pins a counter by default. | |
195 | The nmi watchdog can be disabled as root with | |
196 | ||
197 | echo 0 > /proc/sys/kernel/nmi_watchdog | |
198 | ||
199 | Events from multiple different PMUs cannot be mixed in a group, with | |
200 | some exceptions for software events. | |
201 | ||
202 | LEADER SAMPLING | |
203 | --------------- | |
204 | ||
205 | perf also supports group leader sampling using the :S specifier. | |
206 | ||
207 | perf record -e '{cycles,instructions}:S' ... | |
208 | perf report --group | |
209 | ||
210 | Normally all events in a event group sample, but with :S only | |
211 | the first event (the leader) samples, and it only reads the values of the | |
212 | other events in the group. | |
213 | ||
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214 | OPTIONS |
215 | ------- | |
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216 | |
217 | Without options all known events will be listed. | |
218 | ||
219 | To limit the list use: | |
220 | ||
221 | . 'hw' or 'hardware' to list hardware events such as cache-misses, etc. | |
222 | ||
223 | . 'sw' or 'software' to list software events such as context switches, etc. | |
224 | ||
225 | . 'cache' or 'hwcache' to list hardware cache events such as L1-dcache-loads, etc. | |
226 | ||
227 | . 'tracepoint' to list all tracepoint events, alternatively use | |
228 | 'subsys_glob:event_glob' to filter by tracepoint subsystems such as sched, | |
229 | block, etc. | |
230 | ||
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231 | . 'pmu' to print the kernel supplied PMU events. |
232 | ||
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233 | . If none of the above is matched, it will apply the supplied glob to all |
234 | events, printing the ones that match. | |
235 | ||
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236 | . As a last resort, it will do a substring search in all event names. |
237 | ||
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238 | One or more types can be used at the same time, listing the events for the |
239 | types specified. | |
386b05e3 | 240 | |
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241 | Support raw format: |
242 | ||
243 | . '--raw-dump', shows the raw-dump of all the events. | |
244 | . '--raw-dump [hw|sw|cache|tracepoint|pmu|event_glob]', shows the raw-dump of | |
245 | a certain kind of events. | |
246 | ||
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247 | SEE ALSO |
248 | -------- | |
249 | linkperf:perf-stat[1], linkperf:perf-top[1], | |
1cf4a063 | 250 | linkperf:perf-record[1], |
85f8f966 | 251 | http://www.intel.com/sdm/[Intel® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide], |
2055fdaf | 252 | http://support.amd.com/us/Processor_TechDocs/24593_APM_v2.pdf[AMD64 Architecture Programmer’s Manual Volume 2: System Programming] |