1. 06 Mar, 2009 14 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: 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
  2. 05 Mar, 2009 14 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
    • Steven Rostedt's avatar
      tracing: remove extra latency_trace method from trace structure · 5fd73f86
      Steven Rostedt authored
      
      
      Impact: clean up
      
      The trace and latency_trace function pointers are identical for
      every tracer but the function tracer. The differences in the function
      tracer are trivial (latency output puts paranthesis around parent).
      
      This patch removes the latency_trace pointer and all prints will
      now just use the trace output function pointer.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      5fd73f86
    • Steven Rostedt's avatar
      tracing: add latency output format option · c032ef64
      Steven Rostedt authored
      
      
      With the removal of the latency_trace file, we lost the ability
      to see some of the finer details in a trace. Like the state of
      interrupts enabled, the preempt count, need resched, and if we
      are in an interrupt handler, softirq handler or not.
      
      This patch simply creates an option to bring back the old format.
      This also removes the warning about an unused variable that held
      the latency_trace file operations.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      c032ef64
    • Steven Rostedt's avatar
      tracing: fix seq read from trace files · e74da523
      Steven Rostedt authored
      
      
      The buffer used by trace_seq was updated incorrectly. Instead
      of consuming what was actually read, it consumed the rest of the
      buffer on reads.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      e74da523
    • Steven Rostedt's avatar
      tracing: do not return EFAULT if read copied anything · 2dc5d12b
      Steven Rostedt authored
      
      
      Impact: fix trace read to conform to standards
      
      Andrew Morton, Theodore Tso and H. Peter Anvin brought to my attention
      that a userspace read should not return -EFAULT if it succeeded in
      copying anything. It should only return -EFAULT if it failed to copy
      at all.
      
      This patch modifies the check of copy_from_user and updates the return
      code appropriately.
      
      I also used H. Peter Anvin's short cut rule to just test ret == count.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      2dc5d12b
    • Steven Rostedt's avatar
      ring-buffer: fix timestamp in partial ring_buffer_page_read · 4f3640f8
      Steven Rostedt authored
      
      
      If a partial ring_buffer_page_read happens, then some of the
      incremental timestamps may be lost. This patch writes the
      recent timestamp into the page that is passed back to the caller.
      
      A partial ring_buffer_page_read is where the full page would not
      be written back to the user, and instead, just part of the page
      is copied to the user. A full page would be a page swap with the
      ring buffer and the timestamps would be correct.
      Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
      4f3640f8
  3. 04 Mar, 2009 12 commits