1. 15 Mar, 2013 2 commits
  2. 14 May, 2010 1 commit
    • Steven Rostedt's avatar
      tracing: Allow events to share their print functions · a9a57763
      Steven Rostedt authored
      Multiple events may use the same method to print their data.
      Instead of having all events have a pointer to their print funtions,
      the trace_event structure now points to a trace_event_functions structure
      that will hold the way to print ouf the event.
      
      The event itself is now passed to the print function to let the print
      function know what kind of event it should print.
      
      This opens the door to consolidating the way several events print
      their output.
      
         text	   data	    bss	    dec	    hex	filename
      4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
      4900382	1048964	 861512	6810858	 67ecea	vmlinux.init
      4900446	1049028	 861512	6810986	 67ed6a	vmlinux.preprint
      
      This change slightly increases the size but is needed for the next change.
      
      v3: Fix the branch tracer events to handle this change.
      
      v2: Fix the new function graph tracer event calls to handle this change.
      Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      a9a57763
  3. 11 Sep, 2009 1 commit
  4. 09 Jun, 2009 1 commit
  5. 25 May, 2009 1 commit
    • Lai Jiangshan's avatar
      tracing: add trace_event_read_lock() · 4f535968
      Lai Jiangshan authored
      I found that there is nothing to protect event_hash in
      ftrace_find_event(). Rcu protects the event hashlist
      but not the event itself while we use it after its extraction
      through ftrace_find_event().
      
      This lack of a proper locking in this spot opens a race
      window between any event dereferencing and module removal.
      
      Eg:
      
      --Task A--
      
      print_trace_line(trace) {
        event = find_ftrace_event(trace)
      
      --Task B--
      
      trace_module_remove_events(mod) {
        list_trace_events_module(ev, mod) {
          unregister_ftrace_event(ev->event) {
            hlist_del(ev->event->node)
              list_del(....)
          }
        }
      }
      |--> module removed, the event has been dropped
      
      --Task A--
      
        event->print(trace); // Dereferencing freed memory
      
      If the event retrieved belongs to a module and this module
      is concurrently removed, we may end up dereferencing a data
      from a freed module.
      
      RCU could solve this, but it would add latency to the kernel and
      forbid tracers output callbacks to call any sleepable code.
      So this fix converts 'trace_event_mutex' to a read/write semaphore,
      and adds trace_event_read_lock() to protect ftrace_find_event().
      
      [ Impact: fix possible freed memory dereference in ftrace ]
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <4A114806.7090302@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      4f535968
  6. 14 Apr, 2009 2 commits
    • Steven Rostedt's avatar
      tracing/events: move declarations from trace directory to core include · 97f20251
      Steven Rostedt authored
      In preparation to allowing trace events to happen in modules, we need
      to move some of the local declarations in the kernel/trace directory
      into include/linux.
      
      This patch simply moves the declarations and performs no context changes.
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      97f20251
    • Steven Rostedt's avatar
      tracing: make trace_seq operations available for core kernel · 9504504c
      Steven Rostedt authored
      In the process to make TRACE_EVENT macro work for modules, the trace_seq
      operations must be available for core kernel code.
      
      These operations are quite useful and can be used for other implementations.
      
      The main idea is that we create a trace_seq handle that acts very much
      like the seq_file handle.
      
      	struct trace_seq *s = kmalloc(sizeof(*s, GFP_KERNEL);
      
      	trace_seq_init(s);
      	trace_seq_printf(s, "some data %d\n", variable);
      
      	printk("%s", s->buffer);
      
      The main use is to allow a top level function call several other functions
      that may store printf like data into the buffer. Then at the end, the top
      level function can process all the data with any method it would like to.
      It could be passed to userspace, output via printk or even use seq_file:
      
      	trace_seq_to_user(s, ubuf, cnt);
      	seq_puts(m, s->buffer);
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      9504504c
  7. 31 Mar, 2009 3 commits
  8. 25 Mar, 2009 1 commit
    • Steven Rostedt's avatar
      tracing: adding function timings to function profiler · 0706f1c4
      Steven Rostedt authored
      If the function graph trace is enabled, the function profiler will
      use it to take the timing of the functions.
      
       cat /debug/tracing/trace_stat/functions
      
        Function                               Hit    Time
        --------                               ---    ----
        mwait_idle                             127    183028.4 us
        schedule                                26    151997.7 us
        __schedule                              31    151975.1 us
        sys_wait4                                2    74080.53 us
        do_wait                                  2    74077.80 us
        sys_newlstat                           138    39929.16 us
        do_path_lookup                         179    39845.79 us
        vfs_lstat_fd                           138    39761.97 us
        user_path_at                           153    39469.58 us
        path_walk                              179    39435.76 us
        __link_path_walk                       189    39143.73 us
      [...]
      
      Note the times are skewed due to the function graph tracer not taking
      into account schedules.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      0706f1c4
  9. 19 Mar, 2009 1 commit
  10. 06 Mar, 2009 1 commit
    • Frederic Weisbecker's avatar
      tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk() · 769b0441
      Frederic Weisbecker authored
      Impact: faster and lighter tracing
      
      Now that we have trace_bprintk() which is faster and consume lesser
      memory than trace_printk() and has the same purpose, we can now drop
      the old implementation in favour of the binary one from trace_bprintk(),
      which means we move all the implementation of trace_bprintk() to
      trace_printk(), so the Api doesn't change except that we must now use
      trace_seq_bprintk() to print the TRACE_PRINT entries.
      
      Some changes result of this:
      
      - Previously, trace_bprintk depended of a single tracer and couldn't
        work without. This tracer has been dropped and the whole implementation
        of trace_printk() (like the module formats management) is now integrated
        in the tracing core (comes with CONFIG_TRACING), though we keep the file
        trace_printk (previously trace_bprintk.c) where we can find the module
        management. Thus we don't overflow trace.c
      
      - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries.
      
      - change a bit trace_printk/trace_vprintk macros to support non-builtin formats
        constants, and fix 'const' qualifiers warnings. But this is all transparent for
        developers.
      
      - etc...
      
      V2:
      
      - Rebase against last changes
      - Fix mispell on the changelog
      
      V3:
      
      - Rebase against last changes (moving trace_printk() to kernel.h)
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      769b0441
  11. 05 Mar, 2009 1 commit
  12. 04 Feb, 2009 1 commit
  13. 03 Feb, 2009 2 commits
    • Arnaldo Carvalho de Melo's avatar
      trace: Change struct trace_event callbacks parameter list · 2c9b238e
      Arnaldo Carvalho de Melo authored
      Impact: API change
      
      The trace_seq and trace_entry are in trace_iterator, where there are
      more fields that may be needed by tracers, so just pass the
      tracer_iterator as is already the case for struct tracer->print_line.
      Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      2c9b238e
    • Frederic Weisbecker's avatar
      trace: better manage the context info for events · c4a8e8be
      Frederic Weisbecker authored
      Impact: make trace_event more convenient for tracers
      
      All tracers (for the moment) that use the struct trace_event want to
      have the context info printed before their own output: the pid/cmdline,
      cpu, and timestamp.
      
      But some other tracers that want to implement their trace_event
      callbacks will not necessary need these information or they may want to
      format them as they want.
      
      This patch adds a new default-enabled trace option:
      TRACE_ITER_CONTEXT_INFO When disabled through:
      
      echo nocontext-info > /debugfs/tracing/trace_options
      
      The pid, cpu and timestamps headers will not be printed.
      
      IE with the sched_switch tracer with context-info (default):
      
           bash-2935 [001] 100.356561: 2935:120:S ==> [001]  0:140:R <idle>
         <idle>-0    [000] 100.412804:    0:140:R   + [000] 11:115:S events/0
         <idle>-0    [000] 100.412816:    0:140:R ==> [000] 11:115:R events/0
       events/0-11   [000] 100.412829:   11:115:S ==> [000]  0:140:R <idle>
      
      Without context-info:
      
       2935:120:S ==> [001]  0:140:R <idle>
          0:140:R   + [000] 11:115:S events/0
          0:140:R ==> [000] 11:115:R events/0
         11:115:S ==> [000]  0:140:R <idle>
      
      A tracer can disable it at runtime by clearing the bit
      TRACE_ITER_CONTEXT_INFO in trace_flags.
      
      The print routines were renamed to trace_print_context and
      trace_print_lat_context, so that they can be used by tracers if they
      want to use them for one of the trace_event callbacks.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      c4a8e8be
  14. 16 Jan, 2009 2 commits
  15. 29 Dec, 2008 2 commits
    • Steven Rostedt's avatar
      ftrace: change trace.c to use registered events · f633cef0
      Steven Rostedt authored
      Impact: rework trace.c to use new event register API
      
      Almost every ftrace event has to implement its output display in
      trace.c through a different function. Some events did not handle
      all the formats (trace, latency-trace, raw, hex, binary), and
      this method does not scale well.
      
      This patch converts the format functions to use the event API to
      find the event and and print its format. Currently, we have
      a print function for trace, latency_trace, raw, hex and binary.
      A trace_nop_print is available if the event wants to avoid output
      on a particular format.
      
      Perhaps other tracers could use this in the future (like mmiotrace and
      function_graph).
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      f633cef0
    • Steven Rostedt's avatar
      ftrace: set up trace event hash infrastructure · f0868d1e
      Steven Rostedt authored
      Impact: simplify/generalize/refactor trace.c
      
      The trace.c file is becoming more difficult to maintain due to the
      growing number of events. There is several formats that an event may
      be printed. This patch sets up the infrastructure of an event hash to
      allow for events to register how they should be printed.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      f0868d1e