1. 10 Mar, 2009 14 commits
    • Steven Rostedt's avatar
      tracing: remove funky whitespace in the trace code · ef18012b
      Steven Rostedt authored
      
      
      Impact: clean up
      
      There existed a lot of <space><tab>'s in the tracing code. This
      patch removes them.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      ef18012b
    • Steven Rostedt's avatar
      tracing: update comments to match event code macros · 0e3d0f05
      Steven Rostedt authored
      
      
      Impact: clean up / comments
      
      The comments that described the ftrace macros to manipulate the
      TRACE_EVENT and TRACE_FORMAT macros no longer match the code.
      This patch updates them.
      Reported-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      0e3d0f05
    • Steven Rostedt's avatar
      tracing: document TRACE_EVENT macro in tracepoint.h · 823f9124
      Steven Rostedt authored
      
      
      Impact: clean up / comments
      
      Kosaki Motohiro asked about an explanation to the TRACE_EVENT macro.
      Ingo Molnar replied with a nice description.
      
      This patch takes the description that Ingo wrote (with some slight
      modifications) and adds it to the tracepoint.h file.
      Reported-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      823f9124
    • Steven Rostedt's avatar
      tracing: flip the TP_printk and TP_fast_assign in the TRACE_EVENT macro · 30a8fecc
      Steven Rostedt authored
      
      
      Impact: clean up
      
      In trying to stay consistant with the C style format in the TRACE_EVENT
      macro, it makes more sense to do the printk after the assigning of
      the variables.
      Reported-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      30a8fecc
    • Steven Rostedt's avatar
      tracing: add back the available_events file · 2314c4ae
      Steven Rostedt authored
      
      
      The event directory files type and available_types were no longer
      needed with the new TRACE_EVENT_FORMAT macros, they were deleted.
      But by accident the available_events file was also removed.
      This patch brings it back.
      Reported-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      2314c4ae
    • Steven Rostedt's avatar
      tracing: do not allow modifying the ftrace events via the event files · 40e26815
      Steven Rostedt authored
      
      
      Impact: fix to prevent crash on calling NULL function pointer
      
      The ftrace internal records have their format exported via the event
      system under the ftrace subsystem. These are only for exporting the
      format to allow binary readers to be able to parse them in a binary
      output.
      
      The ftrace subsystem events can only be enabled via the ftrace tracers
      and do not have a registering function. The event files expect the
      event record to have registering function and will call it directly.
      Passing in a ftrace subsystem event will cause the kernel to crash
      because it will execute a NULL pointer.
      
      This patch prevents the ftrace subsystem from being viewable to the
      event enabling files.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      40e26815
    • Steven Rostedt's avatar
      tracing: fix printk format specifier · ce8eb2bf
      Steven Rostedt authored
      
      
      Impact: clean up
      
      The offsetof and sizeof are of type size_t, and instead of typecasting
      them to unsigned int for printk formatting, one could just use %zu.
      Reported-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      ce8eb2bf
    • Steven Rostedt's avatar
      tracing: remove obsolete TRACE_EVENT_FORMAT macro · 157587d7
      Steven Rostedt authored
      
      
      Impact: clean up
      
      The TRACE_EVENT_FORMAT macro is no longer used by trace points
      and only the DECLARE_TRACE, TRACE_FORMAT or TRACE_EVENT macros should
      be used by them. Although the TRACE_EVENT_FORMAT macro is still used
      by the internal tracing utility, it should not be used in core
      kernel code.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      157587d7
    • Steven Rostedt's avatar
      tracing: convert irq trace points to new macros · d6e2ca4c
      Steven Rostedt authored
      
      
      Impact: enhancement
      
      Converted the two irq trace point macros. The entry macro copies
      the name of the irq handler, thus it is better to simply use the
      TRACE_FORMAT macro which uses the trace_printk.
      
      The return of the handler does not need to record the name, thus
      the faster C style handler is more approriate.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      d6e2ca4c
    • Steven Rostedt's avatar
      tracing: convert the sched trace points to the TRACE_EVENT macros · 12b5fdb8
      Steven Rostedt authored
      
      
      Impact: enhancement
      
      This patch converts the rest of the sched trace points to use the new
      more powerful TRACE_EVENT macro.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      12b5fdb8
    • Steven Rostedt's avatar
      tracing: new format for specialized trace points · da4d0302
      Steven Rostedt authored
      
      
      Impact: clean up and enhancement
      
      The TRACE_EVENT_FORMAT macro looks quite ugly and is limited in its
      ability to save data as well as to print the record out. Working with
      Ingo Molnar, we came up with a new format that is much more pleasing to
      the eye of C developers. This new macro is more C style than the old
      macro, and is more obvious to what it does.
      
      Here's the example. The only updated macro in this patch is the
      sched_switch trace point.
      
      The old method looked like this:
      
       TRACE_EVENT_FORMAT(sched_switch,
              TP_PROTO(struct rq *rq, struct task_struct *prev,
                      struct task_struct *next),
              TP_ARGS(rq, prev, next),
              TP_FMT("task %s:%d ==> %s:%d",
                    prev->comm, prev->pid, next->comm, next->pid),
              TRACE_STRUCT(
                      TRACE_FIELD(pid_t, prev_pid, prev->pid)
                      TRACE_FIELD(int, prev_prio, prev->prio)
                      TRACE_FIELD_SPECIAL(char next_comm[TASK_COMM_LEN],
                                          next_comm,
                                          TP_CMD(memcpy(TRACE_ENTRY->next_comm,
                                                       next->comm,
                                                       TASK_COMM_LEN)))
                      TRACE_FIELD(pid_t, next_pid, next->pid)
                      TRACE_FIELD(int, next_prio, next->prio)
              ),
              TP_RAW_FMT("prev %d:%d ==> next %s:%d:%d")
              );
      
      The above method is hard to read and requires two format fields.
      
      The new method:
      
       /*
        * Tracepoint for task switches, performed by the scheduler:
        *
        * (NOTE: the 'rq' argument is not used by generic trace events,
        *        but used by the latency tracer plugin. )
        */
       TRACE_EVENT(sched_switch,
      
      	TP_PROTO(struct rq *rq, struct task_struct *prev,
      		 struct task_struct *next),
      
      	TP_ARGS(rq, prev, next),
      
      	TP_STRUCT__entry(
      		__array(	char,	prev_comm,	TASK_COMM_LEN	)
      		__field(	pid_t,	prev_pid			)
      		__field(	int,	prev_prio			)
      		__array(	char,	next_comm,	TASK_COMM_LEN	)
      		__field(	pid_t,	next_pid			)
      		__field(	int,	next_prio			)
      	),
      
      	TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
      		__entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
      		__entry->next_comm, __entry->next_pid, __entry->next_prio),
      
      	TP_fast_assign(
      		memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
      		__entry->prev_pid	= prev->pid;
      		__entry->prev_prio	= prev->prio;
      		memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
      		__entry->next_pid	= next->pid;
      		__entry->next_prio	= next->prio;
      	)
       );
      
      This macro is called TRACE_EVENT, it is broken up into 5 parts:
      
       TP_PROTO:        the proto type of the trace point
       TP_ARGS:         the arguments of the trace point
       TP_STRUCT_entry: the structure layout of the entry in the ring buffer
       TP_printk:       the printk format
       TP_fast_assign:  the method used to write the entry into the ring buffer
      
      The structure is the definition of how the event will be saved in the
      ring buffer. The printk is used by the internal tracing in case of
      an oops, and the kernel needs to print out the format of the record
      to the console. This the TP_printk gives a means to show the records
      in a human readable format. It is also used to print out the data
      from the trace file.
      
      The TP_fast_assign is executed directly. It is basically like a C function,
      where the __entry is the handle to the record.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      da4d0302
    • Steven Rostedt's avatar
      tracing: use generic __stringify · 9cc26a26
      Steven Rostedt authored
      
      
      Impact: clean up
      
      This removes the custom made STR(x) macros in the tracer and uses
      the generic __stringify macro instead.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      9cc26a26
    • Steven Rostedt's avatar
      tracing: replace TP<var> with TP_<var> · 2939b046
      Steven Rostedt authored
      
      
      Impact: clean up
      
      The macros TPPROTO, TPARGS, TPFMT, TPRAWFMT, and TPCMD all look a bit
      ugly. This patch adds an underscore to their names.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      2939b046
    • Steven Rostedt's avatar
      tracing: typecast sizeof and offsetof to unsigned int · 156b5f17
      Steven Rostedt authored
      
      
      Impact: fix compiler warnings
      
      On x86_64 sizeof and offsetof are treated as long, where as on x86_32
      they are int. This patch typecasts them to unsigned int to avoid
      one arch giving warnings while the other does not.
      Reported-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      156b5f17
  2. 09 Mar, 2009 2 commits
    • Ingo Molnar's avatar
      tracing: optimize trace_printk() · 7bffc23e
      Ingo Molnar authored
      
      
      Impact: micro-optimization
      
      trace_printk() does this unconditionally:
      
      	trace_printk_fmt = fmt;
      
      Where trace_printk_fmt is an entry into a global array. This is
      very SMP-unfriendly.
      
      So only write it once per bootup.
      
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      7bffc23e
    • Ingo Molnar's avatar
      tracing: trace_printk() fix, move format array to data section · 8a20d84d
      Ingo Molnar authored
      
      
      Impact: fix kernel crash when using trace_printk()
      
      trace_printk_fmt section is defined into the readonly section.
      But we do:
      
      	trace_printk_fmt = fmt;
      
      to fill in that table of format strings - which is not read-only.
      Under CONFIG_DEBUG_RODATA=y this crashes ...
      
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      8a20d84d
  3. 06 Mar, 2009 15 commits
    • Ingo Molnar's avatar
      tracing: trace_bprintk() cleanups · 9de36825
      Ingo Molnar authored
      
      
      Impact: cleanup
      
      Remove a few leftovers and clean up the code a bit.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      9de36825
    • 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: add trace_bprintk() · 1ba28e02
      Lai Jiangshan authored
      
      
      Impact: add a generic printk() for tracing, like trace_printk()
      
      trace_bprintk() uses the infrastructure to record events on ring_buffer.
      
      [ fweisbec@gmail.com: ported to latest -tip, made it work if
        !CONFIG_MODULES, never free the format strings from modules
        because we can't keep track of them and conditionnaly create
        the ftrace format strings section (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: <1236356510-8381-4-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      1ba28e02
    • 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
    • Ingo Molnar's avatar
      546e5354
    • Frederic Weisbecker's avatar
      vsprintf: unify the format decoding layer for its 3 users · fef20d9c
      Frederic Weisbecker authored
      
      
      An new optimization is making its way to ftrace. Its purpose is to
      make trace_printk() consuming less memory and be faster.
      
      Written by Lai Jiangshan, the approach is to delay the formatting
      job from tracing time to output time.
      
      Currently, a call to trace_printk() will format the whole string and
      insert it into the ring buffer. Then you can read it on /debug/tracing/trace
      file.
      
      The new implementation stores the address of the format string and
      the binary parameters into the ring buffer, making the packet more compact
      and faster to insert.
      Later, when the user exports the traces, the format string is retrieved
      with the binary parameters and the formatting job is eventually done.
      
      The new implementation rewrites a lot of format decoding bits from
      vsnprintf() function, making now 3 differents functions to maintain
      in their duplicated parts of printf format decoding bits.
      
      Suggested by Ingo Molnar, this patch tries to factorize the most
      possible common bits from these functions.
      The real common part between them is the format decoding. Although
      they do somewhat similar jobs, their way to export or import the parameters
      is very different. Thus, only the decoding layer is extracted, unless you see
      other parts that could be worth factorized.
      
      Changes in V2:
      
      - Address a suggestion from Linus to group the format_decode() parameters inside
        a structure.
      
      Changes in v3:
      
      - Address other cleanups suggested by Ingo and Linus such as passing the
        printf_spec struct to the format helpers: pointer()/number()/string()
        Note that this struct is passed by copy and not by address. This is to
        avoid side effects because these functions often change these values and the
        changes shoudn't be persistant when a callee helper returns.
        It would be too risky.
      
      - Various cleanups (code alignement, switch/case instead of if/else fountains).
      
      - Fix a bug that printed the first format specifier following a %p
      
      Changes in v4:
      
      - drop unapropriate const qualifier loss while casting fmt to a char *
        (thanks to Vegard Nossum for having pointed this out).
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1236356510-8381-6-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      fef20d9c
    • Lai Jiangshan's avatar
      vsprintf: add binary printf · 4370aa4a
      Lai Jiangshan authored
      
      
      Impact: add new APIs for binary trace printk infrastructure
      
      vbin_printf(): write args to binary buffer, string is copied
      when "%s" is occurred.
      
      bstr_printf(): read from binary buffer for args and format a string
      
      [fweisbec@gmail.com: rebase]
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      LKML-Reference: <1236356510-8381-2-git-send-email-fweisbec@gmail.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      4370aa4a
    • Ingo Molnar's avatar
      tracing, power-trace: make it build even if the power-tracer is turned off · af438c0f
      Ingo Molnar authored
      
      
      Impact: build fix
      
      The 'struct power_trace' definition is needed (for the event tracer) even if
      the power-tracer plugin is turned off in the .config.
      
      Cc: Steven Rostedt <srostedt@redhat.com>
      LKML-Reference: <20090306104106.GF31042@elte.hu>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      af438c0f
    • KOSAKI Motohiro's avatar
      tracing: fix deadlock when setting set_ftrace_pid · 10dd3ebe
      KOSAKI Motohiro authored
      Impact: fix deadlock while using set_ftrace_pid
      
      Reproducer:
      
      	# cd /sys/kernel/debug/tracing
      	# echo $$ > set_ftrace_pid
      
      	then, console becomes hung.
      
      Details:
      
      when writing set_ftracepid, kernel callstack is following
      
      	ftrace_pid_write()
      		mutex_lock(&ftrace_lock);
      		ftrace_update_pid_func()
      			mutex_lock(&ftrace_lock);
      			mutex_unlock(&ftrace_lock);
      		mutex_unlock(&ftrace_lock);
      
      then, system always deadlocks when ftrace_pid_write() is called.
      
      In past days, ftrace_pid_write() used ftrace_start_lock, but
      commit e6ea44e9
      
       consolidated
      ftrace_start_lock to ftrace_lock.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      Cc: Steven Rostedt <srostedt@redhat.com>
      LKML-Reference: <20090306151155.0778.A69D9226@jp.fujitsu.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      10dd3ebe
    • KOSAKI Motohiro's avatar
      tracing: current tip/master can't enable ftrace · 422d3c7a
      KOSAKI Motohiro authored
      After commit 40ada30f,
      "make menuconfig" doesn't display "Tracer" item.
      
      Following modification restores it.
      422d3c7a
    • Ingo Molnar's avatar
      Merge branch 'tip/tracing/ftrace' of... · bc722f50
      Ingo Molnar authored
      Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
      bc722f50
    • Ingo Molnar's avatar
    • Steven Rostedt's avatar
      tracing: add format files for ftrace default entries · 770cb243
      Steven Rostedt authored
      
      
      Impact: allow user apps to read binary format of basic ftrace entries
      
      Currently, only defined raw events export their formats so a binary
      reader can parse them. There's no reason that the default ftrace entries
      can't export their formats.
      
      This patch adds a subsystem called "ftrace" in the events directory
      that includes the ftrace entries for basic ftrace recorded items.
      
      These only have three files in the events directory:
      
       type             : printf
       available_types  : printf
       format           : format for the event entry
      
      For example:
      
       # cat /debug/tracing/events/ftrace/wakeup/format
      name: wakeup
      ID: 3
      format:
              field:unsigned char type;       offset:0;       size:1;
              field:unsigned char flags;      offset:1;       size:1;
              field:unsigned char preempt_count;      offset:2;       size:1;
              field:int pid;  offset:4;       size:4;
              field:int tgid; offset:8;       size:4;
      
              field:unsigned int prev_pid;    offset:12;      size:4;
              field:unsigned char prev_prio;  offset:16;      size:1;
              field:unsigned char prev_state; offset:17;      size:1;
              field:unsigned int next_pid;    offset:20;      size:4;
              field:unsigned char next_prio;  offset:24;      size:1;
              field:unsigned char next_state; offset:25;      size:1;
              field:unsigned int next_cpu;    offset:28;      size:4;
      
      print fmt: "%u:%u:%u  ==+ %u:%u:%u [%03u]"
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      770cb243
    • Steven Rostedt's avatar
      tracing: move print of event format to separate file · 33b0c229
      Steven Rostedt authored
      
      
      Impact: clean up
      
      Move the macro that creates the event format file to a separate header.
      This will allow the default ftrace events to use this same macro
      to create the formats to read those events.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      33b0c229
    • Steven Rostedt's avatar
      tracing: make all file_operations const · 5e2336a0
      Steven Rostedt authored
      
      
      Impact: cleanup
      
      All file_operations structures should be constant. No one is going to
      change them.
      Reported-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      5e2336a0
  4. 05 Mar, 2009 9 commits
    • Ingo Molnar's avatar
      tracing: clean up menu · 40ada30f
      Ingo Molnar authored
      
      
      Clean up menu structure, introduce TRACING_SUPPORT switch that signals
      whether an architecture supports various instrumentation mechanisms.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      40ada30f
    • Steven Rostedt's avatar
      tracing: add tracing_on/tracing_off to kernel.h · 2002c258
      Steven Rostedt authored
      
      
      Impact: cleanup
      
      The functions tracing_start/tracing_stop have been moved to kernel.h.
      These are not the functions a developer most likely wants to use
      when they want to insert a place to stop tracing and restart it from
      user space.
      
      tracing_start/tracing_stop was created to work with things like
      suspend to ram, where even calling smp_processor_id() can crash the
      system. The tracing_start/tracing_stop was used to stop the tracer from
      doing anything. These are still light weight functions, but add a bit
      more overhead to be able to stop the tracers. They also have no interface
      back to userland. That is, if the kernel calls tracing_stop, userland
      can not start tracing.
      
      What a developer most likely wants to use is tracing_on/tracing_off.
      These are very light weight functions (simply sets or clears a bit).
      These functions just stop recording into the ring buffer. The tracers
      don't even know that this happens except that they would receive NULL
      from the ring_buffer_lock_reserve function.
      
      Also, there's a way for the user land to enable or disable this bit.
      In debugfs/tracing/tracing_on, a user may echo "0" (same as tracing_off())
      or echo "1" (same as tracing_on()) into this file. This becomes handy when
      a kernel developer is debugging and wants tracing to turn off when it
      hits an anomaly. Then the developer can examine the trace, and restart
      tracing if they want to try again (echo 1 > tracing_on).
      
      This patch moves the prototypes for tracing_on/tracing_off to kernel.h
      and comments their use, so that a kernel developer will know how
      to use them.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      2002c258
    • Frederic Weisbecker's avatar
      tracing/function-graph-tracer: use the more lightweight local clock · 0012693a
      Frederic Weisbecker authored
      
      
      Impact: decrease hangs risks with the graph tracer on slow systems
      
      Since the function graph tracer can spend too much time on timer
      interrupts, it's better now to use the more lightweight local
      clock. Anyway, the function graph traces are more reliable on a
      per cpu trace.
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      LKML-Reference: <49af243d.06e9300a.53ad.ffff840c@mx.google.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0012693a
    • Ingo Molnar's avatar
      tracing: move utility functions from ftrace.h to kernel.h · 526211bc
      Ingo Molnar authored
      
      
      Make common utility functions such as trace_printk() and
      tracing_start()/tracing_stop() generally available to kernel
      code.
      
      Cc: Steven Rostedt <srostedt@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      526211bc
    • Ingo Molnar's avatar
      tracing: rename ftrace_printk() => trace_printk() · 5e1607a0
      Ingo Molnar authored
      
      
      Impact: cleanup
      
      Use a more generic name - this also allows the prototype to move
      to kernel.h and be generally available to kernel developers who
      want to do some quick tracing.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      5e1607a0
    • Ingo Molnar's avatar
      Merge branch 'tip/tracing/ftrace' of... · 53664738
      Ingo Molnar authored
      Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
      53664738
    • Ingo Molnar's avatar
      c4ef144a
    • Steven Rostedt's avatar
      tracing: have latency tracers set the latency format · e9d25fe6
      Steven Rostedt authored
      
      
      The latency tracers (irqsoff, preemptoff, preemptirqsoff, and wakeup)
      are pretty useless with the default output format. This patch makes them
      automatically enable the latency format when they are selected. They
      also record the state of the latency option, and if it was not enabled
      when selected, they disable it on reset.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      e9d25fe6
    • Steven Rostedt's avatar
      tracing: consolidate print_lat_fmt and print_trace_fmt · 27d48be8
      Steven Rostedt authored
      
      
      Impact: clean up
      
      Both print_lat_fmt and print_trace_fmt do pretty much the same thing
      except for one different function call. This patch consolidates the
      two functions and adds an if statement to perform the difference.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      27d48be8