diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/trace/user_events.rst | 14 |
1 files changed, 3 insertions, 11 deletions
diff --git a/Documentation/trace/user_events.rst b/Documentation/trace/user_events.rst index bddedabaca80..c180936f49fc 100644 --- a/Documentation/trace/user_events.rst +++ b/Documentation/trace/user_events.rst @@ -7,7 +7,7 @@ user_events: User-based Event Tracing Overview -------- User based trace events allow user processes to create events and trace data -that can be viewed via existing tools, such as ftrace, perf and eBPF. +that can be viewed via existing tools, such as ftrace and perf. To enable this feature, build your kernel with CONFIG_USER_EVENTS=y. Programs can view status of the events via @@ -67,8 +67,7 @@ The command string format is as follows:: Supported Flags ^^^^^^^^^^^^^^^ -**BPF_ITER** - EBPF programs attached to this event will get the raw iovec -struct instead of any data copies for max performance. +None yet Field Format ^^^^^^^^^^^^ @@ -160,7 +159,7 @@ The following values are defined to aid in checking what has been attached: **EVENT_STATUS_FTRACE** - Bit set if ftrace has been attached (Bit 0). -**EVENT_STATUS_PERF** - Bit set if perf/eBPF has been attached (Bit 1). +**EVENT_STATUS_PERF** - Bit set if perf has been attached (Bit 1). Writing Data ------------ @@ -204,13 +203,6 @@ It's advised for user programs to do the following:: **NOTE:** *The write_index is not emitted out into the trace being recorded.* -EBPF ----- -EBPF programs that attach to a user-based event tracepoint are given a pointer -to a struct user_bpf_context. The bpf context contains the data type (which can -be a user or kernel buffer, or can be a pointer to the iovec) and the data -length that was emitted (minus the write_index). - Example Code ------------ See sample code in samples/user_events. |