perf record: Add ability to sample call branches

This change “perf record: Add ability to sample call branches” in Linux kernel is authored by Stephane Eranian <eranian [at] google.com> on Tue Oct 13 09:09:11 2015 +0200.

perf record: Add ability to sample call branches

This patch add a new branch type sampling filter to perf record.
It is named 'call' and maps to PERF_SAMPLE_BRANCH_CALL. It samples
direct call branches only, unlike 'any_call' which includes indirect
calls as well.

 $ perf record -j call -e cycles .....

The man page is updated accordingly.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: khandual@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1444720151-10275-5-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

This Linux change may have been applied to various maintained Linux releases and you can find Linux releases including commit 43e41ad.

There are 2 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 tools/perf/Documentation/perf-record.txt | 1 +
 tools/perf/util/parse-branch-options.c   | 1 +
 2 files changed, 2 insertions(+)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 2e9ce77..b027d28 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -236,6 +236,7 @@ following filters are defined:
         - any_call: any function call or system call
         - any_ret: any function return or system call return
         - ind_call: any indirect branch
+        - call: direct calls, including far (to/from kernel) calls
         - u:  only when the branch target is at the user level
         - k: only when the branch target is in the kernel
         - hv: only when the target is at the hypervisor level
diff --git a/tools/perf/util/parse-branch-options.c b/tools/perf/util/parse-branch-options.c
index a3b1e13..355eecf 100644
--- a/tools/perf/util/parse-branch-options.c
+++ b/tools/perf/util/parse-branch-options.c
@@ -27,6 +27,7 @@ struct branch_mode {
 	BRANCH_OPT("no_tx", PERF_SAMPLE_BRANCH_NO_TX),
 	BRANCH_OPT("cond", PERF_SAMPLE_BRANCH_COND),
 	BRANCH_OPT("ind_jmp", PERF_SAMPLE_BRANCH_IND_JUMP),
+	BRANCH_OPT("call", PERF_SAMPLE_BRANCH_CALL),
 	BRANCH_END
 };
 

The commit for this change in Linux stable tree is 43e41ad (patch).

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