1. 26 May, 2009 1 commit
    • Steven Rostedt's avatar
      tracing: add __print_flags for events · be74b73a
      Steven Rostedt authored
      
      
      Developers have been asking for the ability in the ftrace event tracer
      to display names of bits in a flags variable.
      
      Instead of printing out c2, it would be easier to read FOO|BAR|GOO,
      assuming that FOO is bit 1, BAR is bit 6 and GOO is bit 7.
      
      Some examples where this would be useful are the state flags in a context
      switch, kmalloc flags, and even permision flags in accessing files.
      
      [
        v2 changes include:
      
        Frederic Weisbecker's idea of using a mask instead of bits,
        thus we can output GFP_KERNEL instead of GPF_WAIT|GFP_IO|GFP_FS.
      
        Li Zefan's idea of allowing the caller of __print_flags to add their
        own delimiter (or no delimiter) where we can get for file permissions
        rwx instead of r|w|x.
      ]
      
      [
        v3 changes:
      
         Christoph Hellwig's idea of using an array instead of va_args.
      ]
      
      [ Impact: better displaying of flags in trace output ]
      
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      be74b73a
  2. 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
  3. 15 May, 2009 1 commit
  4. 06 May, 2009 1 commit
  5. 25 Apr, 2009 1 commit
    • Steven Rostedt's avatar
      tracing/events: reuse trace event ids after overflow · 060fa5c8
      Steven Rostedt authored
      
      
      With modules being able to add trace events, and the max trace event
      counter is 16 bits (65536) we can overflow the counter easily
      with a simple while loop adding and removing modules that contain
      trace events.
      
      This patch links together the registered trace events and on overflow
      searches for available trace event ids. It will still fail if
      over 65536 events are registered, but considering that a typical
      kernel only has 22000 functions, 65000 events should be sufficient.
      
      Reported-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      060fa5c8
  6. 24 Apr, 2009 1 commit
    • Steven Rostedt's avatar
      tracing: increase size of number of possible events · 89ec0dee
      Steven Rostedt authored
      
      
      With the new event tracing registration, we must increase the number
      of events that can be registered. Currently the type field is only
      one byte, which leaves us only 256 possible events.
      
      Since we do not save the CPU number in the tracer anymore (it is determined
      by the per cpu ring buffer that is used) we have an extra byte to use.
      
      This patch increases the size of type from 1 byte (256 events) to
      2 bytes (65,536 events).
      
      It also adds a WARN_ON_ONCE if we exceed that limit.
      
      [ Impact: allow more than 255 events ]
      
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      89ec0dee
  7. 14 Apr, 2009 1 commit
  8. 07 Apr, 2009 1 commit
    • Lai Jiangshan's avatar
      tracing: fix incorrect return type of ns2usecs() · cf8e3474
      Lai Jiangshan authored
      
      
      Impact: fix time output bug in 32bits system
      
      ns2usecs() returns 'long', it's incorrect.
      
      (In i386)
      ...
                <idle>-0     [000]   521.442100: _spin_lock <-tick_do_update_jiffies64
                <idle>-0     [000]   521.442101: do_timer <-tick_do_update_jiffies64
                <idle>-0     [000]   521.442102: update_wall_time <-do_timer
                <idle>-0     [000]   521.442102: update_xtime_cache <-update_wall_time
      ....
      (It always print the time less than 2200 seconds besides ...)
      Because 'long' is 32bits in i386. ( (1<<31) useconds is about 2200 seconds)
      
      ...
                <idle>-0     [001] 4154502640.134759: rcu_bh_qsctr_inc <-__do_softirq
                <idle>-0     [001] 4154502640.134760: _local_bh_enable <-__do_softirq
                <idle>-0     [001] 4154502640.134761: idle_cpu <-irq_exit
      ...
      (very large value)
      Because 'long' is a signed type and it is 32bits in i386.
      
      Changes in v2:
      return 'unsigned long long' instead of 'cycle_t'
      
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      LKML-Reference: <49D05D10.4030009@cn.fujitsu.com>
      Reported-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      cf8e3474
  9. 31 Mar, 2009 2 commits
  10. 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
  11. 20 Mar, 2009 1 commit
    • Peter Zijlstra's avatar
      ftrace: ensure every event gets an id · 28bea271
      Peter Zijlstra authored
      
      
      Impact: widen user-space visibe event IDs to all events
      
      Previously only TRACE_EVENT events got ids, because only they
      generated raw output which needs to be demuxed from the trace.
      
      In order to provide a unique ID for each event, register everybody,
      regardless.
      
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <20090319194233.464914218@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      28bea271
  12. 19 Mar, 2009 1 commit
  13. 17 Mar, 2009 1 commit
    • Steven Rostedt's avatar
      tracing: protect reader of cmdline output · 4ca53085
      Steven Rostedt authored
      
      
      Impact: fix to one cause of incorrect comm outputs in trace
      
      The spinlock only protected the creation of a comm <=> pid pair.
      But it was possible that a reader could look up a pid, and get the
      wrong comm because it had no locking.
      
      This also required changing trace_find_cmdline to copy the comm cache
      and not just send back a pointer to it.
      
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      4ca53085
  14. 13 Mar, 2009 1 commit
    • Frederic Weisbecker's avatar
      tracing/core: bring back raw trace_printk for dynamic formats strings · 48ead020
      Frederic Weisbecker authored
      
      
      Impact: fix callsites with dynamic format strings
      
      Since its new binary implementation, trace_printk() internally uses static
      containers for the format strings on each callsites. But the value is
      assigned once at build time, which means that it can't take dynamic
      formats.
      
      So this patch unearthes the raw trace_printk implementation for the callers
      that will need trace_printk to be able to carry these dynamic format
      strings. The trace_printk() macro will use the appropriate implementation
      for each callsite. Most of the time however, the binary implementation will
      still be used.
      
      The other impact of this patch is that mmiotrace_printk() will use the old
      implementation because it calls the low level trace_vprintk and we can't
      guess here whether the format passed in it is dynamic or not.
      
      Some parts of this patch have been written by Steven Rostedt (most notably
      the part that chooses the appropriate implementation for each callsites).
      
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      48ead020
  15. 10 Mar, 2009 1 commit
  16. 06 Mar, 2009 2 commits
    • 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
    • Lai Jiangshan's avatar
      tracing: infrastructure for supporting binary record · 1427cdf0
      Lai Jiangshan authored
      
      
      Impact: save on memory for tracing
      
      Current tracers are typically using a struct(like struct ftrace_entry,
      struct ctx_switch_entry, struct special_entr etc...)to record a binary
      event. These structs can only record a their own kind of events.
      A new kind of tracer need a new struct and a lot of code too handle it.
      
      So we need a generic binary record for events. This infrastructure
      is for this purpose.
      
      [fweisbec@gmail.com: rebase against latest -tip, make it safe while sched
      tracing as reported by Steven Rostedt]
      
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1236356510-8381-3-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      1427cdf0
  17. 05 Mar, 2009 1 commit
  18. 08 Feb, 2009 1 commit
    • Steven Rostedt's avatar
      trace: remove deprecated entry->cpu · 1830b52d
      Steven Rostedt authored
      
      
      Impact: fix to prevent developers from using entry->cpu
      
      With the new ring buffer infrastructure, the cpu for the entry is
      implicit with which CPU buffer it is on.
      
      The original code use to record the current cpu into the generic
      entry header, which can be retrieved by entry->cpu. When the
      ring buffer was introduced, the users were convert to use the
      the cpu number of which cpu ring buffer was in use (this was passed
      to the tracers by the iterator: iter->cpu).
      
      Unfortunately, the cpu item in the entry structure was never removed.
      This allowed for developers to use it instead of the proper iter->cpu,
      unknowingly, using an uninitialized variable. This was not the fault
      of the developers, since it would seem like the logical place to
      retrieve the cpu identifier.
      
      This patch removes the cpu item from the entry structure and fixes
      all the users that should have been using iter->cpu.
      
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      1830b52d
  19. 05 Feb, 2009 1 commit
  20. 04 Feb, 2009 2 commits
  21. 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
  22. 16 Jan, 2009 2 commits
  23. 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