1perf-record(1) 2============== 3 4NAME 5---- 6perf-record - Run a command and record its profile into perf.data 7 8SYNOPSIS 9-------- 10[verse] 11'perf record' [-e <EVENT> | --event=EVENT] [-a] <command> 12'perf record' [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>] 13 14DESCRIPTION 15----------- 16This command runs a command and gathers a performance counter profile 17from it, into perf.data - without displaying anything. 18 19This file can then be inspected later on, using 'perf report'. 20 21 22OPTIONS 23------- 24<command>...:: 25 Any command you can specify in a shell. 26 27-e:: 28--event=:: 29 Select the PMU event. Selection can be: 30 31 - a symbolic event name (use 'perf list' to list all events) 32 33 - a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a 34 hexadecimal event descriptor. 35 36 - a symbolically formed PMU event like 'pmu/param1=0x3,param2/' where 37 'param1', 'param2', etc are defined as formats for the PMU in 38 /sys/bus/event_source/devices/<pmu>/format/*. 39 40 - a symbolically formed event like 'pmu/config=M,config1=N,config3=K/' 41 42 where M, N, K are numbers (in decimal, hex, octal format). Acceptable 43 values for each of 'config', 'config1' and 'config2' are defined by 44 corresponding entries in /sys/bus/event_source/devices/<pmu>/format/* 45 param1 and param2 are defined as formats for the PMU in: 46 /sys/bus/event_source/devices/<pmu>/format/* 47 48 There are also some parameters which are not defined in .../<pmu>/format/*. 49 These params can be used to overload default config values per event. 50 Here are some common parameters: 51 - 'period': Set event sampling period 52 - 'freq': Set event sampling frequency 53 - 'time': Disable/enable time stamping. Acceptable values are 1 for 54 enabling time stamping. 0 for disabling time stamping. 55 The default is 1. 56 - 'call-graph': Disable/enable callgraph. Acceptable str are "fp" for 57 FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and 58 "no" for disable callgraph. 59 - 'stack-size': user stack size for dwarf mode 60 - 'name' : User defined event name. Single quotes (') may be used to 61 escape symbols in the name from parsing by shell and tool 62 like this: name=\'CPU_CLK_UNHALTED.THREAD:cmask=0x1\'. 63 64 See the linkperf:perf-list[1] man page for more parameters. 65 66 Note: If user explicitly sets options which conflict with the params, 67 the value set by the parameters will be overridden. 68 69 Also not defined in .../<pmu>/format/* are PMU driver specific 70 configuration parameters. Any configuration parameter preceded by 71 the letter '@' is not interpreted in user space and sent down directly 72 to the PMU driver. For example: 73 74 perf record -e some_event/@cfg1,@cfg2=config/ ... 75 76 will see 'cfg1' and 'cfg2=config' pushed to the PMU driver associated 77 with the event for further processing. There is no restriction on 78 what the configuration parameters are, as long as their semantic is 79 understood and supported by the PMU driver. 80 81 - a hardware breakpoint event in the form of '\mem:addr[/len][:access]' 82 where addr is the address in memory you want to break in. 83 Access is the memory access type (read, write, execute) it can 84 be passed as follows: '\mem:addr[:[r][w][x]]'. len is the range, 85 number of bytes from specified addr, which the breakpoint will cover. 86 If you want to profile read-write accesses in 0x1000, just set 87 'mem:0x1000:rw'. 88 If you want to profile write accesses in [0x1000~1008), just set 89 'mem:0x1000/8:w'. 90 91 - a group of events surrounded by a pair of brace ("{event1,event2,...}"). 92 Each event is separated by commas and the group should be quoted to 93 prevent the shell interpretation. You also need to use --group on 94 "perf report" to view group events together. 95 96--filter=<filter>:: 97 Event filter. This option should follow an event selector (-e) which 98 selects either tracepoint event(s) or a hardware trace PMU 99 (e.g. Intel PT or CoreSight). 100 101 - tracepoint filters 102 103 In the case of tracepoints, multiple '--filter' options are combined 104 using '&&'. 105 106 - address filters 107 108 A hardware trace PMU advertises its ability to accept a number of 109 address filters by specifying a non-zero value in 110 /sys/bus/event_source/devices/<pmu>/nr_addr_filters. 111 112 Address filters have the format: 113 114 filter|start|stop|tracestop <start> [/ <size>] [@<file name>] 115 116 Where: 117 - 'filter': defines a region that will be traced. 118 - 'start': defines an address at which tracing will begin. 119 - 'stop': defines an address at which tracing will stop. 120 - 'tracestop': defines a region in which tracing will stop. 121 122 <file name> is the name of the object file, <start> is the offset to the 123 code to trace in that file, and <size> is the size of the region to 124 trace. 'start' and 'stop' filters need not specify a <size>. 125 126 If no object file is specified then the kernel is assumed, in which case 127 the start address must be a current kernel memory address. 128 129 <start> can also be specified by providing the name of a symbol. If the 130 symbol name is not unique, it can be disambiguated by inserting #n where 131 'n' selects the n'th symbol in address order. Alternately #0, #g or #G 132 select only a global symbol. <size> can also be specified by providing 133 the name of a symbol, in which case the size is calculated to the end 134 of that symbol. For 'filter' and 'tracestop' filters, if <size> is 135 omitted and <start> is a symbol, then the size is calculated to the end 136 of that symbol. 137 138 If <size> is omitted and <start> is '*', then the start and size will 139 be calculated from the first and last symbols, i.e. to trace the whole 140 file. 141 142 If symbol names (or '*') are provided, they must be surrounded by white 143 space. 144 145 The filter passed to the kernel is not necessarily the same as entered. 146 To see the filter that is passed, use the -v option. 147 148 The kernel may not be able to configure a trace region if it is not 149 within a single mapping. MMAP events (or /proc/<pid>/maps) can be 150 examined to determine if that is a possibility. 151 152 Multiple filters can be separated with space or comma. 153 154--exclude-perf:: 155 Don't record events issued by perf itself. This option should follow 156 an event selector (-e) which selects tracepoint event(s). It adds a 157 filter expression 'common_pid != $PERFPID' to filters. If other 158 '--filter' exists, the new filter expression will be combined with 159 them by '&&'. 160 161-a:: 162--all-cpus:: 163 System-wide collection from all CPUs (default if no target is specified). 164 165-p:: 166--pid=:: 167 Record events on existing process ID (comma separated list). 168 169-t:: 170--tid=:: 171 Record events on existing thread ID (comma separated list). 172 This option also disables inheritance by default. Enable it by adding 173 --inherit. 174 175-u:: 176--uid=:: 177 Record events in threads owned by uid. Name or number. 178 179-r:: 180--realtime=:: 181 Collect data with this RT SCHED_FIFO priority. 182 183--no-buffering:: 184 Collect data without buffering. 185 186-c:: 187--count=:: 188 Event period to sample. 189 190-o:: 191--output=:: 192 Output file name. 193 194-i:: 195--no-inherit:: 196 Child tasks do not inherit counters. 197 198-F:: 199--freq=:: 200 Profile at this frequency. Use 'max' to use the currently maximum 201 allowed frequency, i.e. the value in the kernel.perf_event_max_sample_rate 202 sysctl. Will throttle down to the currently maximum allowed frequency. 203 See --strict-freq. 204 205--strict-freq:: 206 Fail if the specified frequency can't be used. 207 208-m:: 209--mmap-pages=:: 210 Number of mmap data pages (must be a power of two) or size 211 specification with appended unit character - B/K/M/G. The 212 size is rounded up to have nearest pages power of two value. 213 Also, by adding a comma, the number of mmap pages for AUX 214 area tracing can be specified. 215 216--group:: 217 Put all events in a single event group. This precedes the --event 218 option and remains only for backward compatibility. See --event. 219 220-g:: 221 Enables call-graph (stack chain/backtrace) recording. 222 223--call-graph:: 224 Setup and enable call-graph (stack chain/backtrace) recording, 225 implies -g. Default is "fp". 226 227 Allows specifying "fp" (frame pointer) or "dwarf" 228 (DWARF's CFI - Call Frame Information) or "lbr" 229 (Hardware Last Branch Record facility) as the method to collect 230 the information used to show the call graphs. 231 232 In some systems, where binaries are build with gcc 233 --fomit-frame-pointer, using the "fp" method will produce bogus 234 call graphs, using "dwarf", if available (perf tools linked to 235 the libunwind or libdw library) should be used instead. 236 Using the "lbr" method doesn't require any compiler options. It 237 will produce call graphs from the hardware LBR registers. The 238 main limitation is that it is only available on new Intel 239 platforms, such as Haswell. It can only get user call chain. It 240 doesn't work with branch stack sampling at the same time. 241 242 When "dwarf" recording is used, perf also records (user) stack dump 243 when sampled. Default size of the stack dump is 8192 (bytes). 244 User can change the size by passing the size after comma like 245 "--call-graph dwarf,4096". 246 247-q:: 248--quiet:: 249 Don't print any message, useful for scripting. 250 251-v:: 252--verbose:: 253 Be more verbose (show counter open errors, etc). 254 255-s:: 256--stat:: 257 Record per-thread event counts. Use it with 'perf report -T' to see 258 the values. 259 260-d:: 261--data:: 262 Record the sample virtual addresses. 263 264--phys-data:: 265 Record the sample physical addresses. 266 267-T:: 268--timestamp:: 269 Record the sample timestamps. Use it with 'perf report -D' to see the 270 timestamps, for instance. 271 272-P:: 273--period:: 274 Record the sample period. 275 276--sample-cpu:: 277 Record the sample cpu. 278 279-n:: 280--no-samples:: 281 Don't sample. 282 283-R:: 284--raw-samples:: 285Collect raw sample records from all opened counters (default for tracepoint counters). 286 287-C:: 288--cpu:: 289Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a 290comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2. 291In per-thread mode with inheritance mode on (default), samples are captured only when 292the thread executes on the designated CPUs. Default is to monitor all CPUs. 293 294-B:: 295--no-buildid:: 296Do not save the build ids of binaries in the perf.data files. This skips 297post processing after recording, which sometimes makes the final step in 298the recording process to take a long time, as it needs to process all 299events looking for mmap records. The downside is that it can misresolve 300symbols if the workload binaries used when recording get locally rebuilt 301or upgraded, because the only key available in this case is the 302pathname. You can also set the "record.build-id" config variable to 303'skip to have this behaviour permanently. 304 305-N:: 306--no-buildid-cache:: 307Do not update the buildid cache. This saves some overhead in situations 308where the information in the perf.data file (which includes buildids) 309is sufficient. You can also set the "record.build-id" config variable to 310'no-cache' to have the same effect. 311 312-G name,...:: 313--cgroup name,...:: 314monitor only in the container (cgroup) called "name". This option is available only 315in per-cpu mode. The cgroup filesystem must be mounted. All threads belonging to 316container "name" are monitored when they run on the monitored CPUs. Multiple cgroups 317can be provided. Each cgroup is applied to the corresponding event, i.e., first cgroup 318to first event, second cgroup to second event and so on. It is possible to provide 319an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must have 320corresponding events, i.e., they always refer to events defined earlier on the command 321line. If the user wants to track multiple events for a specific cgroup, the user can 322use '-e e1 -e e2 -G foo,foo' or just use '-e e1 -e e2 -G foo'. 323 324If wanting to monitor, say, 'cycles' for a cgroup and also for system wide, this 325command line can be used: 'perf stat -e cycles -G cgroup_name -a -e cycles'. 326 327-b:: 328--branch-any:: 329Enable taken branch stack sampling. Any type of taken branch may be sampled. 330This is a shortcut for --branch-filter any. See --branch-filter for more infos. 331 332-j:: 333--branch-filter:: 334Enable taken branch stack sampling. Each sample captures a series of consecutive 335taken branches. The number of branches captured with each sample depends on the 336underlying hardware, the type of branches of interest, and the executed code. 337It is possible to select the types of branches captured by enabling filters. The 338following filters are defined: 339 340 - any: any type of branches 341 - any_call: any function call or system call 342 - any_ret: any function return or system call return 343 - ind_call: any indirect branch 344 - call: direct calls, including far (to/from kernel) calls 345 - u: only when the branch target is at the user level 346 - k: only when the branch target is in the kernel 347 - hv: only when the target is at the hypervisor level 348 - in_tx: only when the target is in a hardware transaction 349 - no_tx: only when the target is not in a hardware transaction 350 - abort_tx: only when the target is a hardware transaction abort 351 - cond: conditional branches 352 - save_type: save branch type during sampling in case binary is not available later 353 354+ 355The option requires at least one branch type among any, any_call, any_ret, ind_call, cond. 356The privilege levels may be omitted, in which case, the privilege levels of the associated 357event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege 358levels are subject to permissions. When sampling on multiple events, branch stack sampling 359is enabled for all the sampling events. The sampled branch type is the same for all events. 360The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k 361Note that this feature may not be available on all processors. 362 363--weight:: 364Enable weightened sampling. An additional weight is recorded per sample and can be 365displayed with the weight and local_weight sort keys. This currently works for TSX 366abort events and some memory events in precise mode on modern Intel CPUs. 367 368--namespaces:: 369Record events of type PERF_RECORD_NAMESPACES. 370 371--transaction:: 372Record transaction flags for transaction related events. 373 374--per-thread:: 375Use per-thread mmaps. By default per-cpu mmaps are created. This option 376overrides that and uses per-thread mmaps. A side-effect of that is that 377inheritance is automatically disabled. --per-thread is ignored with a warning 378if combined with -a or -C options. 379 380-D:: 381--delay=:: 382After starting the program, wait msecs before measuring. This is useful to 383filter out the startup phase of the program, which is often very different. 384 385-I:: 386--intr-regs:: 387Capture machine state (registers) at interrupt, i.e., on counter overflows for 388each sample. List of captured registers depends on the architecture. This option 389is off by default. It is possible to select the registers to sample using their 390symbolic names, e.g. on x86, ax, si. To list the available registers use 391--intr-regs=\?. To name registers, pass a comma separated list such as 392--intr-regs=ax,bx. The list of register is architecture dependent. 393 394--user-regs:: 395Capture user registers at sample time. Same arguments as -I. 396 397--running-time:: 398Record running and enabled time for read events (:S) 399 400-k:: 401--clockid:: 402Sets the clock id to use for the various time fields in the perf_event_type 403records. See clock_gettime(). In particular CLOCK_MONOTONIC and 404CLOCK_MONOTONIC_RAW are supported, some events might also allow 405CLOCK_BOOTTIME, CLOCK_REALTIME and CLOCK_TAI. 406 407-S:: 408--snapshot:: 409Select AUX area tracing Snapshot Mode. This option is valid only with an 410AUX area tracing event. Optionally the number of bytes to capture per 411snapshot can be specified. In Snapshot Mode, trace data is captured only when 412signal SIGUSR2 is received. 413 414--proc-map-timeout:: 415When processing pre-existing threads /proc/XXX/mmap, it may take a long time, 416because the file may be huge. A time out is needed in such cases. 417This option sets the time out limit. The default value is 500 ms. 418 419--switch-events:: 420Record context switch events i.e. events of type PERF_RECORD_SWITCH or 421PERF_RECORD_SWITCH_CPU_WIDE. 422 423--clang-path=PATH:: 424Path to clang binary to use for compiling BPF scriptlets. 425(enabled when BPF support is on) 426 427--clang-opt=OPTIONS:: 428Options passed to clang when compiling BPF scriptlets. 429(enabled when BPF support is on) 430 431--vmlinux=PATH:: 432Specify vmlinux path which has debuginfo. 433(enabled when BPF prologue is on) 434 435--buildid-all:: 436Record build-id of all DSOs regardless whether it's actually hit or not. 437 438--aio[=n]:: 439Use <n> control blocks in asynchronous (Posix AIO) trace writing mode (default: 1, max: 4). 440Asynchronous mode is supported only when linking Perf tool with libc library 441providing implementation for Posix AIO API. 442 443--all-kernel:: 444Configure all used events to run in kernel space. 445 446--all-user:: 447Configure all used events to run in user space. 448 449--timestamp-filename 450Append timestamp to output file name. 451 452--timestamp-boundary:: 453Record timestamp boundary (time of first/last samples). 454 455--switch-output[=mode]:: 456Generate multiple perf.data files, timestamp prefixed, switching to a new one 457based on 'mode' value: 458 "signal" - when receiving a SIGUSR2 (default value) or 459 <size> - when reaching the size threshold, size is expected to 460 be a number with appended unit character - B/K/M/G 461 <time> - when reaching the time threshold, size is expected to 462 be a number with appended unit character - s/m/h/d 463 464 Note: the precision of the size threshold hugely depends 465 on your configuration - the number and size of your ring 466 buffers (-m). It is generally more precise for higher sizes 467 (like >5M), for lower values expect different sizes. 468 469A possible use case is to, given an external event, slice the perf.data file 470that gets then processed, possibly via a perf script, to decide if that 471particular perf.data snapshot should be kept or not. 472 473Implies --timestamp-filename, --no-buildid and --no-buildid-cache. 474The reason for the latter two is to reduce the data file switching 475overhead. You can still switch them on with: 476 477 --switch-output --no-no-buildid --no-no-buildid-cache 478 479--dry-run:: 480Parse options then exit. --dry-run can be used to detect errors in cmdline 481options. 482 483'perf record --dry-run -e' can act as a BPF script compiler if llvm.dump-obj 484in config file is set to true. 485 486--tail-synthesize:: 487Instead of collecting non-sample events (for example, fork, comm, mmap) at 488the beginning of record, collect them during finalizing an output file. 489The collected non-sample events reflects the status of the system when 490record is finished. 491 492--overwrite:: 493Makes all events use an overwritable ring buffer. An overwritable ring 494buffer works like a flight recorder: when it gets full, the kernel will 495overwrite the oldest records, that thus will never make it to the 496perf.data file. 497 498When '--overwrite' and '--switch-output' are used perf records and drops 499events until it receives a signal, meaning that something unusual was 500detected that warrants taking a snapshot of the most current events, 501those fitting in the ring buffer at that moment. 502 503'overwrite' attribute can also be set or canceled for an event using 504config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'. 505 506Implies --tail-synthesize. 507 508SEE ALSO 509-------- 510linkperf:perf-stat[1], linkperf:perf-list[1] 511