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