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Diffstat (limited to 'tools/perf/Documentation/perf-trace.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-trace.txt | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-trace.txt b/tools/perf/Documentation/perf-trace.txt index 13293de88..1ab078236 100644 --- a/tools/perf/Documentation/perf-trace.txt +++ b/tools/perf/Documentation/perf-trace.txt @@ -117,9 +117,42 @@ the thread executes on the designated CPUs. Default is to monitor all CPUs. --syscalls:: Trace system calls. This options is enabled by default. +--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. + --event:: Trace other events, see 'perf list' for a complete list. +--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. |