perf record: Add support for sampling taken branch
This patch adds a new option to enable taken branch stack
sampling, i.e., leverage the PERF_SAMPLE_BRANCH_STACK feature
of perf_events.
There is a new option to active this mode: -b.
It is possible to pass a set of filters to select the type of
branches to sample.
The following filters are available:
- any : any type of branches
- any_call : any function call or system call
- any_ret : any function return or system call return
- any_ind : any indirect branch
- 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 branch target is in the hypervisor
Filters can be combined by passing a comma separated list
to the option:
$ perf record -b any_call,u -e cycles:u branchy
Signed-off-by: Roberto Agostino Vitillo <ravitillo@lbl.gov>
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-13-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index a1fd1cd..f421f7c 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -126,6 +126,10 @@
attr->watermark = 0;
attr->wakeup_events = 1;
}
+ if (opts->branch_stack) {
+ attr->sample_type |= PERF_SAMPLE_BRANCH_STACK;
+ attr->branch_sample_type = opts->branch_stack;
+ }
attr->mmap = track;
attr->comm = track;