1perf-trace(1) 2============= 3 4NAME 5---- 6perf-trace - strace inspired tool 7 8SYNOPSIS 9-------- 10[verse] 11'perf trace' 12'perf trace record' 13 14DESCRIPTION 15----------- 16This command will show the events associated with the target, initially 17syscalls, but other system events like pagefaults, task lifetime events, 18scheduling events, etc. 19 20This is a live mode tool in addition to working with perf.data files like 21the other perf tools. Files can be generated using the 'perf record' command 22but the session needs to include the raw_syscalls events (-e 'raw_syscalls:*'). 23Alternatively, 'perf trace record' can be used as a shortcut to 24automatically include the raw_syscalls events when writing events to a file. 25 26The following options apply to perf trace; options to perf trace record are 27found in the perf record man page. 28 29OPTIONS 30------- 31 32-a:: 33--all-cpus:: 34 System-wide collection from all CPUs. 35 36-e:: 37--expr:: 38 List of syscalls to show, currently only syscall names. 39 Prefixing with ! shows all syscalls but the ones specified. You may 40 need to escape it. 41 42-D msecs:: 43--delay msecs:: 44After starting the program, wait msecs before measuring. This is useful to 45filter out the startup phase of the program, which is often very different. 46 47-o:: 48--output=:: 49 Output file name. 50 51-p:: 52--pid=:: 53 Record events on existing process ID (comma separated list). 54 55-t:: 56--tid=:: 57 Record events on existing thread ID (comma separated list). 58 59-u:: 60--uid=:: 61 Record events in threads owned by uid. Name or number. 62 63--filter-pids=:: 64 Filter out events for these pids and for 'trace' itself (comma separated list). 65 66-v:: 67--verbose=:: 68 Verbosity level. 69 70--no-inherit:: 71 Child tasks do not inherit counters. 72 73-m:: 74--mmap-pages=:: 75 Number of mmap data pages (must be a power of two) or size 76 specification with appended unit character - B/K/M/G. The 77 size is rounded up to have nearest pages power of two value. 78 79-C:: 80--cpu:: 81Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a 82comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2. 83In per-thread mode with inheritance mode on (default), Events are captured only when 84the thread executes on the designated CPUs. Default is to monitor all CPUs. 85 86--duration: 87 Show only events that had a duration greater than N.M ms. 88 89--sched: 90 Accrue thread runtime and provide a summary at the end of the session. 91 92-i 93--input 94 Process events from a given perf data file. 95 96-T 97--time 98 Print full timestamp rather time relative to first sample. 99 100--comm:: 101 Show process COMM right beside its ID, on by default, disable with --no-comm. 102 103-s:: 104--summary:: 105 Show only a summary of syscalls by thread with min, max, and average times 106 (in msec) and relative stddev. 107 108-S:: 109--with-summary:: 110 Show all syscalls followed by a summary by thread with min, max, and 111 average times (in msec) and relative stddev. 112 113--tool_stats:: 114 Show tool stats such as number of times fd->pathname was discovered thru 115 hooking the open syscall return + vfs_getname or via reading /proc/pid/fd, etc. 116 117-F=[all|min|maj]:: 118--pf=[all|min|maj]:: 119 Trace pagefaults. Optionally, you can specify whether you want minor, 120 major or all pagefaults. Default value is maj. 121 122--syscalls:: 123 Trace system calls. This options is enabled by default. 124 125--call-graph [mode,type,min[,limit],order[,key][,branch]]:: 126 Setup and enable call-graph (stack chain/backtrace) recording. 127 See `--call-graph` section in perf-record and perf-report 128 man pages for details. The ones that are most useful in 'perf trace' 129 are 'dwarf' and 'lbr', where available, try: 'perf trace --call-graph dwarf'. 130 131 Using this will, for the root user, bump the value of --mmap-pages to 4 132 times the maximum for non-root users, based on the kernel.perf_event_mlock_kb 133 sysctl. This is done only if the user doesn't specify a --mmap-pages value. 134 135--kernel-syscall-graph:: 136 Show the kernel callchains on the syscall exit path. 137 138--event:: 139 Trace other events, see 'perf list' for a complete list. 140 141--max-stack:: 142 Set the stack depth limit when parsing the callchain, anything 143 beyond the specified depth will be ignored. Note that at this point 144 this is just about the presentation part, i.e. the kernel is still 145 not limiting, the overhead of callchains needs to be set via the 146 knobs in --call-graph dwarf. 147 148 Implies '--call-graph dwarf' when --call-graph not present on the 149 command line, on systems where DWARF unwinding was built in. 150 151 Default: /proc/sys/kernel/perf_event_max_stack when present for 152 live sessions (without --input/-i), 127 otherwise. 153 154--min-stack:: 155 Set the stack depth limit when parsing the callchain, anything 156 below the specified depth will be ignored. Disabled by default. 157 158 Implies '--call-graph dwarf' when --call-graph not present on the 159 command line, on systems where DWARF unwinding was built in. 160 161--proc-map-timeout:: 162 When processing pre-existing threads /proc/XXX/mmap, it may take a long time, 163 because the file may be huge. A time out is needed in such cases. 164 This option sets the time out limit. The default value is 500 ms. 165 166PAGEFAULTS 167---------- 168 169When tracing pagefaults, the format of the trace is as follows: 170 171<min|maj>fault [<ip.symbol>+<ip.offset>] => <addr.dso@addr.offset> (<map type><addr level>). 172 173- min/maj indicates whether fault event is minor or major; 174- ip.symbol shows symbol for instruction pointer (the code that generated the 175 fault); if no debug symbols available, perf trace will print raw IP; 176- addr.dso shows DSO for the faulted address; 177- map type is either 'd' for non-executable maps or 'x' for executable maps; 178- addr level is either 'k' for kernel dso or '.' for user dso. 179 180For symbols resolution you may need to install debugging symbols. 181 182Please be aware that duration is currently always 0 and doesn't reflect actual 183time it took for fault to be handled! 184 185When --verbose specified, perf trace tries to print all available information 186for both IP and fault address in the form of dso@symbol+offset. 187 188EXAMPLES 189-------- 190 191Trace only major pagefaults: 192 193 $ perf trace --no-syscalls -F 194 195Trace syscalls, major and minor pagefaults: 196 197 $ perf trace -F all 198 199 1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.) 200 201 As you can see, there was major pagefault in python process, from 202 CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so. 203 204SEE ALSO 205-------- 206linkperf:perf-record[1], linkperf:perf-script[1] 207