| perf-trace(1) | |
| ============= | |
| NAME | |
| ---- | |
| perf-trace - strace inspired tool | |
| SYNOPSIS | |
| -------- | |
| [verse] | |
| 'perf trace' | |
| 'perf trace record' | |
| DESCRIPTION | |
| ----------- | |
| This command will show the events associated with the target, initially | |
| syscalls, but other system events like pagefaults, task lifetime events, | |
| scheduling events, etc. | |
| This is a live mode tool in addition to working with perf.data files like | |
| the other perf tools. Files can be generated using the 'perf record' command | |
| but the session needs to include the raw_syscalls events (-e 'raw_syscalls:*'). | |
| Alternatively, 'perf trace record' can be used as a shortcut to | |
| automatically include the raw_syscalls events when writing events to a file. | |
| The following options apply to perf trace; options to perf trace record are | |
| found in the perf record man page. | |
| OPTIONS | |
| ------- | |
| -a:: | |
| --all-cpus:: | |
| System-wide collection from all CPUs. | |
| -e:: | |
| --expr:: | |
| --event:: | |
| List of syscalls and other perf events (tracepoints, HW cache events, | |
| etc) to show. Globbing is supported, e.g.: "epoll_*", "*msg*", etc. | |
| See 'perf list' for a complete list of events. | |
| Prefixing with ! shows all syscalls but the ones specified. You may | |
| need to escape it. | |
| -D msecs:: | |
| --delay msecs:: | |
| After starting the program, wait msecs before measuring. This is useful to | |
| filter out the startup phase of the program, which is often very different. | |
| -o:: | |
| --output=:: | |
| Output file name. | |
| -p:: | |
| --pid=:: | |
| Record events on existing process ID (comma separated list). | |
| -t:: | |
| --tid=:: | |
| Record events on existing thread ID (comma separated list). | |
| -u:: | |
| --uid=:: | |
| Record events in threads owned by uid. Name or number. | |
| --filter-pids=:: | |
| Filter out events for these pids and for 'trace' itself (comma separated list). | |
| -v:: | |
| --verbose=:: | |
| Verbosity level. | |
| --no-inherit:: | |
| Child tasks do not inherit counters. | |
| -m:: | |
| --mmap-pages=:: | |
| Number of mmap data pages (must be a power of two) or size | |
| specification with appended unit character - B/K/M/G. The | |
| size is rounded up to have nearest pages power of two value. | |
| -C:: | |
| --cpu:: | |
| Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a | |
| comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2. | |
| In per-thread mode with inheritance mode on (default), Events are captured only when | |
| the thread executes on the designated CPUs. Default is to monitor all CPUs. | |
| --duration: | |
| Show only events that had a duration greater than N.M ms. | |
| --sched: | |
| Accrue thread runtime and provide a summary at the end of the session. | |
| -i | |
| --input | |
| Process events from a given perf data file. | |
| -T | |
| --time | |
| Print full timestamp rather time relative to first sample. | |
| --comm:: | |
| Show process COMM right beside its ID, on by default, disable with --no-comm. | |
| -s:: | |
| --summary:: | |
| Show only a summary of syscalls by thread with min, max, and average times | |
| (in msec) and relative stddev. | |
| -S:: | |
| --with-summary:: | |
| Show all syscalls followed by a summary by thread with min, max, and | |
| average times (in msec) and relative stddev. | |
| --tool_stats:: | |
| Show tool stats such as number of times fd->pathname was discovered thru | |
| hooking the open syscall return + vfs_getname or via reading /proc/pid/fd, etc. | |
| -F=[all|min|maj]:: | |
| --pf=[all|min|maj]:: | |
| Trace pagefaults. Optionally, you can specify whether you want minor, | |
| major or all pagefaults. Default value is maj. | |
| --syscalls:: | |
| Trace system calls. This options is enabled by default, disable with | |
| --no-syscalls. | |
| --call-graph [mode,type,min[,limit],order[,key][,branch]]:: | |
| Setup and enable call-graph (stack chain/backtrace) recording. | |
| See `--call-graph` section in perf-record and perf-report | |
| man pages for details. The ones that are most useful in 'perf trace' | |
| are 'dwarf' and 'lbr', where available, try: 'perf trace --call-graph dwarf'. | |
| Using this will, for the root user, bump the value of --mmap-pages to 4 | |
| times the maximum for non-root users, based on the kernel.perf_event_mlock_kb | |
| sysctl. This is done only if the user doesn't specify a --mmap-pages value. | |
| --kernel-syscall-graph:: | |
| Show the kernel callchains on the syscall exit path. | |
| --max-stack:: | |
| Set the stack depth limit when parsing the callchain, anything | |
| beyond the specified depth will be ignored. Note that at this point | |
| this is just about the presentation part, i.e. the kernel is still | |
| not limiting, the overhead of callchains needs to be set via the | |
| knobs in --call-graph dwarf. | |
| Implies '--call-graph dwarf' when --call-graph not present on the | |
| command line, on systems where DWARF unwinding was built in. | |
| Default: /proc/sys/kernel/perf_event_max_stack when present for | |
| live sessions (without --input/-i), 127 otherwise. | |
| --min-stack:: | |
| Set the stack depth limit when parsing the callchain, anything | |
| below the specified depth will be ignored. Disabled by default. | |
| Implies '--call-graph dwarf' when --call-graph not present on the | |
| command line, on systems where DWARF unwinding was built in. | |
| --proc-map-timeout:: | |
| When processing pre-existing threads /proc/XXX/mmap, it may take a long time, | |
| because the file may be huge. A time out is needed in such cases. | |
| This option sets the time out limit. The default value is 500 ms. | |
| PAGEFAULTS | |
| ---------- | |
| When tracing pagefaults, the format of the trace is as follows: | |
| <min|maj>fault [<ip.symbol>+<ip.offset>] => <addr.dso@addr.offset> (<map type><addr level>). | |
| - min/maj indicates whether fault event is minor or major; | |
| - ip.symbol shows symbol for instruction pointer (the code that generated the | |
| fault); if no debug symbols available, perf trace will print raw IP; | |
| - addr.dso shows DSO for the faulted address; | |
| - map type is either 'd' for non-executable maps or 'x' for executable maps; | |
| - addr level is either 'k' for kernel dso or '.' for user dso. | |
| For symbols resolution you may need to install debugging symbols. | |
| Please be aware that duration is currently always 0 and doesn't reflect actual | |
| time it took for fault to be handled! | |
| When --verbose specified, perf trace tries to print all available information | |
| for both IP and fault address in the form of dso@symbol+offset. | |
| EXAMPLES | |
| -------- | |
| Trace only major pagefaults: | |
| $ perf trace --no-syscalls -F | |
| Trace syscalls, major and minor pagefaults: | |
| $ perf trace -F all | |
| 1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.) | |
| As you can see, there was major pagefault in python process, from | |
| CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so. | |
| SEE ALSO | |
| -------- | |
| linkperf:perf-record[1], linkperf:perf-script[1] |