• Tuong Lien's avatar
    tipc: enable tracepoints in tipc · b4b9771b
    Tuong Lien authored
    As for the sake of debugging/tracing, the commit enables tracepoints in
    TIPC along with some general trace_events as shown below. It also
    defines some 'tipc_*_dump()' functions that allow to dump TIPC object
    data whenever needed, that is, for general debug purposes, ie. not just
    for the trace_events.
    
    The following trace_events are now available:
    
    - trace_tipc_skb_dump(): allows to trace and dump TIPC msg & skb data,
      e.g. message type, user, droppable, skb truesize, cloned skb, etc.
    
    - trace_tipc_list_dump(): allows to trace and dump any TIPC buffers or
      queues, e.g. TIPC link transmq, socket receive queue, etc.
    
    - trace_tipc_sk_dump(): allows to trace and dump TIPC socket data, e.g.
      sk state, sk type, connection type, rmem_alloc, socket queues, etc.
    
    - trace_tipc_link_dump(): allows to trace and dump TIPC link data, e.g.
      link state, silent_intv_cnt, gap, bc_gap, link queues, etc.
    
    - trace_tipc_node_dump(): allows to trace and dump TIPC node data, e.g.
      node state, active links, capabilities, link entries, etc.
    
    How to use:
    Put the trace functions at any places where we want to dump TIPC data
    or events.
    
    Note:
    a) The dump functions will generate raw data only, that is, to offload
    the trace event's processing, it can require a tool or script to parse
    the data but this should be simple.
    
    b) The trace_tipc_*_dump() should be reserved for a failure cases only
    (e.g. the retransmission failure case) or where we do not expect to
    happen too often, then we can consider enabling these events by default
    since they will almost not take any effects under normal conditions,
    but once the rare condition or failure occurs, we get the dumped data
    fully for post-analysis.
    
    For other trace purposes, we can reuse these trace classes as template
    but different events.
    
    c) A trace_event is only effective when we enable it. To enable the
    TIPC trace_events, echo 1 to 'enable' files in the events/tipc/
    directory in the 'debugfs' file system. Normally, they are located at:
    
    /sys/kernel/debug/tracing/events/tipc/
    
    For example:
    
    To enable the tipc_link_dump event:
    
    echo 1 > /sys/kernel/debug/tracing/events/tipc/tipc_link_dump/enable
    
    To enable all the TIPC trace_events:
    
    echo 1 > /sys/kernel/debug/tracing/events/tipc/enable
    
    To collect the trace data:
    
    cat trace
    
    or
    
    cat trace_pipe > /trace.out &
    
    To disable all the TIPC trace_events:
    
    echo 0 > /sys/kernel/debug/tracing/events/tipc/enable
    
    To clear the trace buffer:
    
    echo > trace
    
    d) Like the other trace_events, the feature like 'filter' or 'trigger'
    is also usable for the tipc trace_events.
    For more details, have a look at:
    
    Documentation/trace/ftrace.txt
    
    MAINTAINERS | add two new files 'trace.h' & 'trace.c' in tipc
    Acked-by: default avatarYing Xue <ying.xue@windriver.com>
    Tested-by: default avatarYing Xue <ying.xue@windriver.com>
    Acked-by: default avatarJon Maloy <jon.maloy@ericsson.com>
    Signed-off-by: default avatarTuong Lien <tuong.t.lien@dektech.com.au>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    b4b9771b
Makefile 549 Bytes