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-rw-r--r--tools/perf/Documentation/perf-trace.txt32
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diff --git a/tools/perf/Documentation/perf-trace.txt b/tools/perf/Documentation/perf-trace.txt
index 13293de..6afe201 100644
--- a/tools/perf/Documentation/perf-trace.txt
+++ b/tools/perf/Documentation/perf-trace.txt
@@ -117,9 +117,41 @@ 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, 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.