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author | Roberto Agostino Vitillo <ravitillo@lbl.gov> | 2012-02-09 22:21:02 (GMT) |
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committer | Ingo Molnar <mingo@elte.hu> | 2012-03-09 07:26:05 (GMT) |
commit | bdfebd848f2a14e639031a0b0e61d7c7ee5e5fd2 (patch) | |
tree | 8ebcc7afda6b506dcd22d44bccdbd925c02b6768 /tools/perf/Documentation | |
parent | b5387528f31d98acedf06e930554b563d87e2383 (diff) | |
download | linux-bdfebd848f2a14e639031a0b0e61d7c7ee5e5fd2.tar.xz |
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>
Diffstat (limited to 'tools/perf/Documentation')
-rw-r--r-- | tools/perf/Documentation/perf-record.txt | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index a5766b4..60bddaf 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -152,6 +152,31 @@ an empty cgroup (monitor all the time) using, e.g., -G foo,,bar. Cgroups must ha corresponding events, i.e., they always refer to events defined earlier on the command line. +-b:: +--branch-stack:: +Enable taken branch stack sampling. Each sample captures a series of consecutive +taken branches. The number of branches captured with each sample depends on the +underlying hardware, the type of branches of interest, and the executed code. +It is possible to select the types of branches captured by enabling filters. The +following filters are defined: + + - 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 target is at the hypervisor level + ++ +At least one of any, any_call, any_ret, any_ind must be provided. The privilege levels may +be ommitted, in which case, the privilege levels of the associated event are applied to the +branch filter. Both kernel (k) and hypervisor (hv) privilege levels are subject to +permissions. When sampling on multiple events, branch stack sampling is enabled for all +the sampling events. The sampled branch type is the same for all events. +Note that taken branch sampling may not be available on all processors. +The various filters must be specified as a comma separated list: -b any_ret,u,k + SEE ALSO -------- linkperf:perf-stat[1], linkperf:perf-list[1] |