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Diffstat (limited to 'tools/perf/Documentation/perf-record.txt')
| -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 a5766b4b0125..60bddaf0e5bd 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] |