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-rw-r--r--tools/perf/Documentation/perf-record.txt9
1 files changed, 7 insertions, 2 deletions
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index b027d28658f2..7ff6a9d0ea0d 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -144,7 +144,7 @@ OPTIONS
--call-graph::
Setup and enable call-graph (stack chain/backtrace) recording,
- implies -g.
+ implies -g. Default is "fp".
Allows specifying "fp" (frame pointer) or "dwarf"
(DWARF's CFI - Call Frame Information) or "lbr"
@@ -154,13 +154,18 @@ OPTIONS
In some systems, where binaries are build with gcc
--fomit-frame-pointer, using the "fp" method will produce bogus
call graphs, using "dwarf", if available (perf tools linked to
- the libunwind library) should be used instead.
+ the libunwind or libdw library) should be used instead.
Using the "lbr" method doesn't require any compiler options. It
will produce call graphs from the hardware LBR registers. The
main limition is that it is only available on new Intel
platforms, such as Haswell. It can only get user call chain. It
doesn't work with branch stack sampling at the same time.
+ When "dwarf" recording is used, perf also records (user) stack dump
+ when sampled. Default size of the stack dump is 8192 (bytes).
+ User can change the size by passing the size after comma like
+ "--call-graph dwarf,4096".
+
-q::
--quiet::
Don't print any message, useful for scripting.