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Commit Graph

379 Commits

Author SHA1 Message Date
Török Edwin
8d7c6a9616 tracing/stack-tracer: fix style issues
Impact: cleanup

Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23 11:53:48 +01:00
Török Edwin
b54d3de9f3 tracing: identify which executable object the userspace address belongs to
Impact: modify+improve the userstacktrace tracing visualization feature

Store thread group leader id, and use it to lookup the address in the
process's map. We could have looked up the address on thread's map,
but the thread might not exist by the time we are called. The process
might not exist either, but if you are reading trace_pipe, that is
unlikely.

Example usage:

 mount -t debugfs nodev /sys/kernel/debug
 cd /sys/kernel/debug/tracing
 echo userstacktrace >iter_ctrl
 echo sym-userobj >iter_ctrl
 echo sched_switch >current_tracer
 echo 1 >tracing_enabled
 cat trace_pipe >/tmp/trace&
 .... run application ...
 echo 0 >tracing_enabled
 cat /tmp/trace

You'll see stack entries like:

   /lib/libpthread-2.7.so[+0xd370]

You can convert them to function/line using:

   addr2line -fie /lib/libpthread-2.7.so 0xd370

Or:

   addr2line -fie /usr/lib/debug/libpthread-2.7.so 0xd370

For non-PIC/PIE executables this won't work:

   a.out[+0x73b]

You need to run the following: addr2line -fie a.out 0x40073b
(where 0x400000 is the default load address of a.out)

Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23 09:45:42 +01:00
Török Edwin
02b67518e2 tracing: add support for userspace stacktraces in tracing/iter_ctrl
Impact: add new (default-off) tracing visualization feature

Usage example:

 mount -t debugfs nodev /sys/kernel/debug
 cd /sys/kernel/debug/tracing
 echo userstacktrace >iter_ctrl
 echo sched_switch >current_tracer
 echo 1 >tracing_enabled
 .... run application ...
 echo 0 >tracing_enabled

Then read one of 'trace','latency_trace','trace_pipe'.

To get the best output you can compile your userspace programs with
frame pointers (at least glibc + the app you are tracing).

Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23 09:25:15 +01:00
Ingo Molnar
a0a70c735e Merge branches 'tracing/profiling', 'tracing/options' and 'tracing/urgent' into tracing/core 2008-11-23 09:10:32 +01:00
Liming Wang
522a110b42 function tracing: fix wrong position computing of stack_trace
Impact: make output of stack_trace complete if buffer overruns

When read buffer overruns, the output of stack_trace isn't complete.

When printing records with seq_printf in t_show, if the read buffer
has overruned by the current record, then this record won't be
printed to user space through read buffer, it will just be dropped in
this printing.

When next printing, t_start should return the "*pos"th record, which
is the one dropped by previous printing, but it just returns
(m->private + *pos)th record.

Here we use a more sane method to implement seq_operations which can
be found in kernel code. Thus we needn't initialize m->private.

About testing, it's not easy to overrun read buffer, but we can use
seq_printf to print more padding bytes in t_show, then it's easy to
check whether or not records are lost.

This commit has been tested on both condition of overrun and non
overrun.

Signed-off-by: Liming Wang <liming.wang@windriver.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-21 08:49:52 +01:00
Ingo Molnar
9676e73a9e Merge branches 'tracing/ftrace' and 'tracing/urgent' into tracing/core
Conflicts:
	kernel/trace/ftrace.c

[ We conflicted here because we backported a few fixes to
  tracing/urgent - which has different internal APIs. ]
2008-11-19 10:04:25 +01:00
Ingo Molnar
86fa2f6067 ftrace: fix selftest locking
Impact: fix self-test boot crash

Self-test failure forgot to re-lock the BKL - crashing the next
initcall:

Testing tracer irqsoff: .. no entries found ..FAILED!
initcall init_irqsoff_tracer+0x0/0x11 returned 0 after 3906 usecs
calling  init_mmio_trace+0x0/0xf @ 1
------------[ cut here ]------------
Kernel BUG at c0c0a915 [verbose debug info unavailable]
invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
last sysfs file:

Pid: 1, comm: swapper Not tainted (2.6.28-rc5-tip #53704)
EIP: 0060:[<c0c0a915>] EFLAGS: 00010286 CPU: 1
EIP is at unlock_kernel+0x10/0x2b
EAX: ffffffff EBX: 00000000 ECX: 00000000 EDX: f7030000
ESI: c12da19c EDI: 00000000 EBP: f7039f54 ESP: f7039f54
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
Process swapper (pid: 1, ti=f7038000 task=f7030000 task.ti=f7038000)
Stack:
 f7039f6c c0164d30 c013fed8 a7d8d7b4 00000000 00000000 f7039f74 c12fb78a
 f7039fd0 c0101132 c12fb77d 00000000 6f727200 6f632072 2d206564 c1002031
 0000000f f7039fa2 f7039fb0 3531b171 00000000 00000000 0000002f c12ca480
Call Trace:
 [<c0164d30>] ? register_tracer+0x66/0x13f
 [<c013fed8>] ? ktime_get+0x19/0x1b
 [<c12fb78a>] ? init_mmio_trace+0xd/0xf
 [<c0101132>] ? do_one_initcall+0x4a/0x111
 [<c12fb77d>] ? init_mmio_trace+0x0/0xf
 [<c015c7e6>] ? init_irq_proc+0x46/0x59
 [<c12e851d>] ? kernel_init+0x104/0x152
 [<c12e8419>] ? kernel_init+0x0/0x152
 [<c01038b7>] ? kernel_thread_helper+0x7/0x10
Code: 58 14 43 75 0a b8 00 9b 2d c1 e8 51 43 7a ff 64 a1 00 a0 37 c1 89 58 14 5b 5d c3 55 64 8b 15 00 a0 37 c1 83 7a 14 00 89 e5 79 04 <0f> 0b eb fe 8b 42 14 48 85 c0 89 42 14 79 0a b8 00 9b 2d c1 e8
EIP: [<c0c0a915>] unlock_kernel+0x10/0x2b SS:ESP 0068:f7039f54
---[ end trace a7919e7f17c0a725 ]---
Kernel panic - not syncing: Attempted to kill init!

So clean up the flow a bit.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-19 10:00:15 +01:00
Ingo Molnar
6d5b43a67a Merge branch 'tip/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/urgent 2008-11-19 09:00:50 +01:00
Steven Rostedt
32464779a1 ftrace: fix dyn ftrace filter selection
Impact: clean up and fix for dyn ftrace filter selection

The previous logic of the dynamic ftrace selection of enabling
or disabling functions was complex and incorrect. This patch simplifies
the code and corrects the usage. This simplification also makes the
code more robust.

Here is the correct logic:

  Given a function that can be traced by dynamic ftrace:

  If the function is not to be traced, disable it if it was enabled.
  (this is if the function is in the set_ftrace_notrace file)

  (filter is on if there exists any functions in set_ftrace_filter file)

  If the filter is on, and we are enabling functions:
    If the function is in set_ftrace_filter, enable it if it is not
      already enabled.
    If the function is not in set_ftrace_filter, disable it if it is not
      already disabled.

  Otherwise, if the filter is off and we are enabling function tracing:
    Enable the function if it is not already enabled.

  Otherwise, if we are disabling function tracing:
    Disable the function if it is not already disabled.

This code now sets or clears the ENABLED flag in the record, and at the
end it will enable the function if the flag is set, or disable the function
if the flag is cleared.

The parameters for the function that does the above logic is also
simplified. Instead of passing in confusing "new" and "old" where
they might be swapped if the "enabled" flag is not set. The old logic
even had one of the above always NULL and had to be filled in. The new
logic simply passes in one parameter called "nop". A "call" is calculated
in the code, and at the end of the logic, when we know we need to either
disable or enable the function, we can then use the "nop" and "call"
properly.

This code is more robust than the previous version.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-19 00:19:47 -05:00
Steven Rostedt
8204327831 ftrace: make filtered functions effective on setting
Impact: fix filter selection to apply when set

It can be confusing when the set_filter_functions is set (or cleared)
and the functions being recorded by the dynamic tracer does not
match.

This patch causes the code to be updated if the function tracer is
enabled and the filter is changed.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-19 00:18:54 -05:00
Steven Rostedt
f10ed36ec1 ftrace: fix set_ftrace_filter
Impact: fix of output of set_ftrace_filter

The commit "ftrace: do not show freed records in
             available_filter_functions"

Removed a bit too much from the set_ftrace_filter code, where we now see
all functions in the set_ftrace_filter file even when we set a filter.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-19 00:17:45 -05:00
Heiko Carstens
a22506347d ftrace: preemptoff selftest not working
Impact: fix preemptoff and preemptirqsoff tracer self-tests

I was wondering why the preemptoff and preemptirqsoff tracer selftests
don't work on s390. After all its just that they get called from
non-preemptible context:

kernel_init() will execute all initcalls, however the first line in
kernel_init() is lock_kernel(), which causes the preempt_count to be
increased. Any later calls to add_preempt_count() (especially those
from the selftests) will therefore not result in a call to
trace_preempt_off() since the check below in add_preempt_count()
will be false:

        if (preempt_count() == val)
                trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));

Hence the trace buffer will be empty.

Fix this by releasing the BKL during the self-tests.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-18 21:54:50 +01:00
Vegard Nossum
641d2f63cf trace: introduce missing mutex_unlock()
Impact: fix tracing buffer mutex leak in case of allocation failure

This error was spotted by this semantic patch:

  http://www.emn.fr/x-info/coccinelle/mut.html

It looks correct as far as I can tell. Please review.

Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-18 21:37:15 +01:00
Julia Lawall
0bb943c7a2 tracing: kernel/trace/trace.c: introduce missing kfree()
Impact: fix memory leak

Error handling code following a kzalloc should free the allocated data.

The semantic match that finds the problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r exists@
local idexpression x;
statement S;
expression E;
identifier f,l;
position p1,p2;
expression *ptr != NULL;
@@

(
if ((x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...)) == NULL) S
|
x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
...
if (x == NULL) S
)
<... when != x
     when != if (...) { <+...x...+> }
x->f = E
...>
(
 return \(0\|<+...x...+>\|ptr\);
|
 return@p2 ...;
)

@script:python@
p1 << r.p1;
p2 << r.p2;
@@

print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-18 16:59:58 +01:00
Frederic Weisbecker
0231022cc3 tracing/function-return-tracer: add the overrun field
Impact: help to find the better depth of trace

We decided to arbitrary define the depth of function return trace as
"20". Perhaps this is not enough. To help finding an optimal depth, we
measure now the overrun: the number of functions that have been missed
for the current thread. By default this is not displayed, we have to
do set a particular flag on the return tracer: echo overrun >
/debug/tracing/trace_options And the overrun will be printed on the
right.

As the trace shows below, the current 20 depth is not enough.

update_wall_time+0x37f/0x8c0 -> update_xtime_cache (345 ns) (Overruns: 2838)
update_wall_time+0x384/0x8c0 -> clocksource_get_next (1141 ns) (Overruns: 2838)
do_timer+0x23/0x100 -> update_wall_time (3882 ns) (Overruns: 2838)
tick_do_update_jiffies64+0xbf/0x160 -> do_timer (5339 ns) (Overruns: 2838)
tick_sched_timer+0x6a/0xf0 -> tick_do_update_jiffies64 (7209 ns) (Overruns: 2838)
vgacon_set_cursor_size+0x98/0x120 -> native_io_delay (2613 ns) (Overruns: 274)
vgacon_cursor+0x16e/0x1d0 -> vgacon_set_cursor_size (33151 ns) (Overruns: 274)
set_cursor+0x5f/0x80 -> vgacon_cursor (36432 ns) (Overruns: 274)
con_flush_chars+0x34/0x40 -> set_cursor (38790 ns) (Overruns: 274)
release_console_sem+0x1ec/0x230 -> up (721 ns) (Overruns: 274)
release_console_sem+0x225/0x230 -> wake_up_klogd (316 ns) (Overruns: 274)
con_flush_chars+0x39/0x40 -> release_console_sem (2996 ns) (Overruns: 274)
con_write+0x22/0x30 -> con_flush_chars (46067 ns) (Overruns: 274)
n_tty_write+0x1cc/0x360 -> con_write (292670 ns) (Overruns: 274)
smp_apic_timer_interrupt+0x2a/0x90 -> native_apic_mem_write (330 ns) (Overruns: 274)
irq_enter+0x17/0x70 -> idle_cpu (413 ns) (Overruns: 274)
smp_apic_timer_interrupt+0x2f/0x90 -> irq_enter (1525 ns) (Overruns: 274)
ktime_get_ts+0x40/0x70 -> getnstimeofday (465 ns) (Overruns: 274)
ktime_get_ts+0x60/0x70 -> set_normalized_timespec (436 ns) (Overruns: 274)
ktime_get+0x16/0x30 -> ktime_get_ts (2501 ns) (Overruns: 274)
hrtimer_interrupt+0x77/0x1a0 -> ktime_get (3439 ns) (Overruns: 274)

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-18 11:11:00 +01:00
Frederic Weisbecker
0619faf657 tracing/ftrace: make nop tracer using tracer flags
Impact: give an example on how to use specific tracer flags

This patch propose to use the nop tracer to provide an
example for using the tracer's custom flags implementation.

V2: replace structures and defines just after the headers includes for
    cleanliness.
V3: replace defines by enum values.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Noonan <steven@uplinklabs.net>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-18 11:10:59 +01:00
Frederic Weisbecker
adf9f19574 tracing/ftrace: implement a set_flag callback for tracers
Impact: give a way to send specific messages to tracers

The current implementation of tracing uses some flags to control the
output of general tracers. But we have no way to implement custom
flags handling for a specific tracer. This patch proposes a new
callback for the struct tracer which called set_flag and a structure
that represents a 32 bits variable flag.

A tracer can implement a struct tracer_flags on which it puts the
initial value of the flag integer. Than it can place a range of flags
with their name and their flag mask on the flag integer. The structure
that implement a single flag is called struct tracer_opt.

These custom flags will be available through the trace_options file
like the general tracing flags. Changing their value is done like the
other general flags. For example if you have a flag that calls "foo",
you can activate it by writing "foo" or "nofoo" on trace_options.

Note that the set_flag callback is optional and is only needed if you
want the flags changing to be signaled to your tracer and let it to
accept or refuse their assignment.

V2: Some arrangements in coding style....

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-18 11:10:58 +01:00
Ingo Molnar
5a209c2d58 Merge branches 'tracing/branch-tracer' and 'tracing/urgent' into tracing/core 2008-11-18 08:52:13 +01:00
Aneesh Kumar K.V
0c726da983 tracing: branch tracer, fix writing to trace/trace_options
Impact: fix trace_options behavior

writing to trace/trace_options use the index of the array
to find the value of the flag. With branch tracer flag
defined conditionally, this breaks writing to trace_options
with branch tracer disabled.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-17 12:07:27 +01:00
Ingo Molnar
3f8e402f34 Merge branches 'tracing/branch-tracer', 'tracing/ftrace', 'tracing/function-return-tracer', 'tracing/tracepoints' and 'tracing/urgent' into tracing/core 2008-11-17 09:36:22 +01:00
walimis
5821e1b74f function tracing: fix wrong pos computing when read buffer has been fulfilled
Impact: make output of available_filter_functions complete

phenomenon:

The first value of dyn_ftrace_total_info is not equal with
`cat available_filter_functions | wc -l`, but they should be equal.

root cause:

When printing functions with seq_printf in t_show, if the read buffer
is just overflowed by current function record, then this function
won't be printed to user space through read buffer, it will
just be dropped. So we can't see this function printing.

So, every time the last function to fill the read buffer, if overflowed,
will be dropped.

This also applies to set_ftrace_filter if set_ftrace_filter has
more bytes than read buffer.

fix:

Through checking return value of seq_printf, if less than 0, we know
this function doesn't be printed. Then we decrease position to force
this function to be printed next time, in next read buffer.

Another little fix is to show correct allocating pages count.

Signed-off-by: walimis <walimisdev@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 08:32:05 +01:00
Frederic Weisbecker
e7d3737ea1 tracing/function-return-tracer: support for dynamic ftrace on function return tracer
This patch adds the support for dynamic tracing on the function return tracer.
The whole difference with normal dynamic function tracing is that we don't need
to hook on a particular callback. The only pro that we want is to nop or set
dynamically the calls to ftrace_caller (which is ftrace_return_caller here).

Some security checks ensure that we are not trying to launch dynamic tracing for
return tracing while normal function tracing is already running.

An example of trace with getnstimeofday set as a filter:

ktime_get_ts+0x22/0x50 -> getnstimeofday (2283 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1396 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1825 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1426 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1524 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1434 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1502 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1404 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1397 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1051 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1314 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1344 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1163 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1390 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1374 ns)

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:57:38 +01:00
Frederic Weisbecker
072b40a156 tracing/branch-tracer: fix a trace recursion on branch tracer
Impact: fix crash when enabling the branch-tracer

When the branch tracer inserts an event through
probe_likely_condition(), it calls local_irq_save() and then results
in a trace recursion.

local_irq_save() -> trace_hardirqs_off() -> trace_hardirqs_off_caller()
	-> unlikely()

The trace_branch.c file is protected by DISABLE_BRANCH_PROFILING but
that doesn't prevent from external call to functions that use
unlikely().

My box crashed each time I tried to set this tracer (sudden and hard
reboot).

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:55:59 +01:00
Frederic Weisbecker
1c80025a49 tracing/ftrace: change the type of the init() callback
Impact: extend the ->init() method with the ability to fail

This bring a way to know if the initialization of a tracer successed.
A tracer must return 0 on success and a traditional error (ie:
-ENOMEM) if it fails.

If a tracer fails to init, it is free to print a detailed warn. The
tracing api will not and switch to a new tracer will just return the
error from the init callback.

Note: this will be used for the return tracer.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:55:23 +01:00
Frederic Weisbecker
e6e7a65aab tracing/ftrace: fix unexpected -EINVAL when longest tracer name is set
Impact: fix confusing write() -EINVAL when changing the tracer

The following commit d9e540762f remade
alive the bug which made the set of a new tracer returning -EINVAL if
this is the longest name of tracer. This patch corrects it.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:53:39 +01:00
Steven Rostedt
ee02a2e5c8 ftrace: make filtered functions effective on setting
Impact: set filtered functions at time the filter is set

It can be confusing when the set_filter_functions is set (or cleared)
and the functions being recorded by the dynamic tracer does not
match.

This patch causes the code to be updated if the function tracer is
enabled and the filter is changed.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:37:46 +01:00
Steven Rostedt
982c350b9e ftrace: fix dyn ftrace filter
Impact: correct implementation of dyn ftrace filter

The old decisions made by the filter algorithm was complex and incorrect.
This lead to inconsistent enabling or disabling of functions when
the filter was used.

This patch simplifies that code and in doing so, corrects the usage
of the filters.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:37:17 +01:00
Steven Rostedt
20e5227e9f ftrace: allow NULL pointers in mcount_loc
Impact: make ftrace_convert_nops() more permissive

Due to the way different architecture linkers combine the data sections
of the mcount_loc (the section that lists all the locations that
call mcount), there may be zeros added in that section. This is usually
due to strange alignments that the linker performs, that pads in zeros.

This patch makes the conversion code to nops skip any pointer in
the mcount_loc section that is NULL.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:36:42 +01:00
Steven Rostedt
31e889098a ftrace: pass module struct to arch dynamic ftrace functions
Impact: allow archs more flexibility on dynamic ftrace implementations

Dynamic ftrace has largly been developed on x86. Since x86 does not
have the same limitations as other architectures, the ftrace interaction
between the generic code and the architecture specific code was not
flexible enough to handle some of the issues that other architectures
have.

Most notably, module trampolines. Due to the limited branch distance
that archs make in calling kernel core code from modules, the module
load code must create a trampoline to jump to what will make the
larger jump into core kernel code.

The problem arises when this happens to a call to mcount. Ftrace checks
all code before modifying it and makes sure the current code is what
it expects. Right now, there is not enough information to handle modifying
module trampolines.

This patch changes the API between generic dynamic ftrace code and
the arch dependent code. There is now two functions for modifying code:

  ftrace_make_nop(mod, rec, addr) - convert the code at rec->ip into
       a nop, where the original text is calling addr. (mod is the
       module struct if called by module init)

  ftrace_make_caller(rec, addr) - convert the code rec->ip that should
       be a nop into a caller to addr.

The record "rec" now has a new field called "arch" where the architecture
can add any special attributes to each call site record.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:36:02 +01:00
Steven Rostedt
d51ad7ac48 ftrace: replace raw_local_irq_save with local_irq_save
Impact: fix lockdep disabling itself when function tracing is enabled

The raw_local_irq_saves used in ftrace is causing problems with
lockdep. (it thinks the irq flags are out of sync and disables
itself with a warning)

The raw ops here are not needed, and the normal local_irq_save is fine.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:35:37 +01:00
Steven Rostedt
918c115410 ftrace: do not process freed records
Impact: keep from converting freed records

When the tracer is started or stopped, it converts all code pointed
to by the saved records into callers to ftrace or nops. When modules
are unloaded, their records are freed, but they still exist within
the record pages.

This patch changes the code to skip over freed records.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:30:17 +01:00
Steven Rostedt
b17e8a37a1 ftrace: disable ftrace on anomalies in trace start and stop
Impact: robust feature to disable ftrace on start or stop tracing on error

Currently only the initial conversion to nops will disable ftrace
on an anomaly. But if an anomaly happens on start or stopping of the
tracer, it will silently fail.

This patch adds a check there too, to disable ftrace and warn if the
conversion fails.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:30:07 +01:00
Steven Rostedt
f3c7ac40a9 ftrace: remove condition from ftrace_record_ip
Impact: let module functions be recorded when dyn ftrace not enabled

When dynamic ftrace had a daemon and a hash to record the locations
of mcount callers at run time, the recording needed to stop when
ftrace was disabled. But now that the recording is done at compile time
and the ftrace_record_ip is only called at boot up and when a module
is loaded, we no longer need to check if ftrace_enabled is set.
In fact, this breaks module load if it is not set because we skip
over module functions.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:29:53 +01:00
Ingo Molnar
c91add5fa6 Merge branches 'tracing/fastboot', 'tracing/ftrace' and 'tracing/urgent' into tracing/core 2008-11-16 07:28:46 +01:00
walimis
b3535c6390 ftrace: remove unnecessary if condition of __unregister_ftrace_function
Because it has goto out before ftrace_list == &ftrace_list_end,
that's to say, we never meet this condition.

Signed-off-by: walimis <walimisdev@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-13 19:36:30 +01:00
Ingo Molnar
ee51a1de7e tracing: fix mmiotrace resizing crash
Pekka reported a crash when resizing the mmiotrace tracer (if only
mmiotrace is enabled).

This happens because in that case we do not allocate the max buffer,
but we try to use it.

Make ring_buffer_resize() idempotent against NULL buffers.

Reported-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-13 14:58:31 +01:00
Steven Rostedt
12ef7d4486 ftrace: CPU buffer start annotation clean ups
Impact: better handling of CPU buffer start annotation

Because of the confusion with the per CPU buffers wrapping where
one CPU might be more active at the end of the trace than the other
CPUs causing that one CPU to have a shorter history. Kernel
developers were confused by the "missing" data of that one CPU
at the beginning of the trace output. An annotation was added to
the trace output to show that the buffer had started:

 # tracer: function
 #
 #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
 #              | |       |          |         |
 ##### CPU 3 buffer started ####
          <idle>-0     [003]   158.192959: smp_apic_timer_interrupt
 [...]
           <idle>-0     [003]   161.556520: default_idle
 ##### CPU 1 buffer started ####
           <idle>-0     [001]   161.592494: hrtimer_force_reprogram
 [etc]

But this annotation gets a bit messy when tracers do not fill the
buffers. This patch does a couple of things:

 One) it adds a flag to trace_options to disable these annotations

 Two) it does not annotate if the tracer did not overflow its buffer.

This makes the output much cleaner.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-13 09:49:24 +01:00
Steven Rostedt
ee6bce5227 ftrace: rename iter_ctrl to trace_options
Impact: rename file /debug/tracing/iter_ctrl to /debug/tracing/trace_options

The original ftrace had a file called "iter_ctrl" that would control
the way the output was iterated. But this file grew into a catch all
for different trace options. This patch renames the file from iter_ctrl
to trace_options to reflect this change.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-13 09:49:23 +01:00
Steven Rostedt
1696b2b0f4 ftrace: show buffer size in kilobytes
Impact: change the units of buffer_size_kb to kilobytes

This patch changes the units of the buffer_size_kb file to kilobytes.
Reading and writing to the file uses kilobytes as units. To help
users to know what units are used, the output of the file now
looks like:

  # cat /debug/tracing/buffer_size_kb
  1408

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-13 09:49:22 +01:00
Steven Rostedt
a94c80e78b ftrace: rename trace_entries to buffer_size_kb
Impact: rename of debugfs file trace_entries to buffer_size_kb

The original ftrace had fixed size entries, and the number of entries
was shown and modified via the file called trace_entries. By converting
to the unified trace buffer, we now allow for variable size entries
which makes the meaning of trace_entries pointless.

Since trace_size might be confused to the size of the trace, this patch
names it "buffer_size_kb" (thanks to Arjan van de Ven for this idea).

[ mingo@elte.hu: changed from buffer_size to buffer_size_kb ]

( Note, the units are still bytes - the next patch changes that,
  to keep the wide rename patch separate from the unit-change patch. )

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-13 09:49:21 +01:00
Ingo Molnar
24de38620d Merge branches 'tracing/branch-tracer', 'tracing/fastboot', 'tracing/function-return-tracer' and 'tracing/urgent' into tracing/core 2008-11-13 09:48:03 +01:00
Steven Rostedt
94b80ffd65 ftrace: rename trace_unlikely.c file
Impact: File name change of trace_unlikely.c

The "unlikely" name for the tracer is quite ugly. We renamed all the
parts of it to "branch" and now it is time to rename the file too.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12 22:28:40 +01:00
Steven Rostedt
80e5ea4506 ftrace: add tracer called branch
Impact: added new branch tracer

Currently the tracing of branch profiling (unlikelys and likelys hit)
is only activated by the iter_ctrl. This patch adds a tracer called
"branch" that will just trace the branch profiling. The advantage
of adding this tracer is that it can be added to the ftrace selftests
on startup.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12 22:28:25 +01:00
Steven Rostedt
9f029e83e9 ftrace: rename unlikely iter_ctrl to branch
Impact: rename of iter_ctrl unlikely to branch

The unlikely name is ugly. This patch converts the iter_ctrl command
"unlikely" and "nounlikely" to "branch" and "nobranch" respectively.

It also renames a lot of internal functions to use "branch" instead
of "unlikely".

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12 22:28:09 +01:00
Steven Rostedt
2ed84eeb88 trace: rename unlikely profiler to branch profiler
Impact: name change of unlikely tracer and profiler

Ingo Molnar suggested changing the config from UNLIKELY_PROFILE
to BRANCH_PROFILING. I never did like the "unlikely" name so I
went one step farther, and renamed all the unlikely configurations
to a "BRANCH" variant.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12 22:27:58 +01:00
Ingo Molnar
68d119f0a6 tracing: finetune branch-tracer output
Steve suggested the to change the output from this:

>  bash-3471  [003]   357.014755: [ MISS ] sched_info_dequeued:sched_stats.h:177
>  bash-3471  [003]   357.014756: [ .... ] update_curr:sched_fair.c:489
>  bash-3471  [003]   357.014758: [ .... ] calc_delta_fair:sched_fair.c:411

to this:

>  bash-3471  [003]   357.014755: [ MISS ] sched_info_dequeued:sched_stats.h:177
>  bash-3471  [003]   357.014756: [  ok  ] update_curr:sched_fair.c:489
>  bash-3471  [003]   357.014758: [  ok  ] calc_delta_fair:sched_fair.c:411

as it makes it clearer to the user what it means exactly.

Acked-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12 14:13:11 +01:00
Ingo Molnar
f88c4ae9f8 tracing: branch tracer, tweak output
Impact: modify the tracer output, to make it a bit easier to read

Change the output from:

>  bash-3471  [003]   357.014755: [INCORRECT] sched_info_dequeued:sched_stats.h:177
>  bash-3471  [003]   357.014756: [correct] update_curr:sched_fair.c:489
>  bash-3471  [003]   357.014758: [correct] calc_delta_fair:sched_fair.c:411

to:

>  bash-3471  [003]   357.014755: [ MISS ] sched_info_dequeued:sched_stats.h:177
>  bash-3471  [003]   357.014756: [ .... ] update_curr:sched_fair.c:489
>  bash-3471  [003]   357.014758: [ .... ] calc_delta_fair:sched_fair.c:411

it's good to have fields aligned vertically, and the only important
information is a prediction miss, so display only that information.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12 11:55:41 +01:00
Steven Rostedt
52f232cb72 tracing: likely/unlikely branch annotation tracer
Impact: new likely/unlikely branch tracer

This patch adds a way to record the instances of the likely() and unlikely()
branch condition annotations.

When "unlikely" is set in /debugfs/tracing/iter_ctrl the unlikely conditions
will be added to any of the ftrace tracers. The change takes effect when
a new tracer is passed into the current_tracer file.

For example:

 bash-3471  [003]   357.014755: [INCORRECT] sched_info_dequeued:sched_stats.h:177
 bash-3471  [003]   357.014756: [correct] update_curr:sched_fair.c:489
 bash-3471  [003]   357.014758: [correct] calc_delta_fair:sched_fair.c:411
 bash-3471  [003]   357.014759: [correct] account_group_exec_runtime:sched_stats.h:356
 bash-3471  [003]   357.014761: [correct] update_curr:sched_fair.c:489
 bash-3471  [003]   357.014763: [INCORRECT] calc_delta_fair:sched_fair.c:411
 bash-3471  [003]   357.014765: [correct] calc_delta_mine:sched.c:1279

Which shows the normal tracer heading, as well as whether the condition was
correct "[correct]" or was mistaken "[INCORRECT]", followed by the function,
file name and line number.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12 11:52:02 +01:00
Steven Rostedt
1f0d69a9fc tracing: profile likely and unlikely annotations
Impact: new unlikely/likely profiler

Andrew Morton recently suggested having an in-kernel way to profile
likely and unlikely macros. This patch achieves that goal.

When configured, every(*) likely and unlikely macro gets a counter attached
to it. When the condition is hit, the hit and misses of that condition
are recorded. These numbers can later be retrieved by:

  /debugfs/tracing/profile_likely    - All likely markers
  /debugfs/tracing/profile_unlikely  - All unlikely markers.

# cat /debug/tracing/profile_unlikely | head
 correct incorrect  %        Function                  File              Line
 ------- ---------  -        --------                  ----              ----
    2167        0   0 do_arch_prctl                  process_64.c         832
       0        0   0 do_arch_prctl                  process_64.c         804
    2670        0   0 IS_ERR                         err.h                34
   71230     5693   7 __switch_to                    process_64.c         673
   76919        0   0 __switch_to                    process_64.c         639
   43184    33743  43 __switch_to                    process_64.c         624
   12740    64181  83 __switch_to                    process_64.c         594
   12740    64174  83 __switch_to                    process_64.c         590

# cat /debug/tracing/profile_unlikely | \
  awk '{ if ($3 > 25) print $0; }' |head -20
   44963    35259  43 __switch_to                    process_64.c         624
   12762    67454  84 __switch_to                    process_64.c         594
   12762    67447  84 __switch_to                    process_64.c         590
    1478      595  28 syscall_get_error              syscall.h            51
       0     2821 100 syscall_trace_leave            ptrace.c             1567
       0        1 100 native_smp_prepare_cpus        smpboot.c            1237
   86338   265881  75 calc_delta_fair                sched_fair.c         408
  210410   108540  34 calc_delta_mine                sched.c              1267
       0    54550 100 sched_info_queued              sched_stats.h        222
   51899    66435  56 pick_next_task_fair            sched_fair.c         1422
       6       10  62 yield_task_fair                sched_fair.c         982
    7325     2692  26 rt_policy                      sched.c              144
       0     1270 100 pre_schedule_rt                sched_rt.c           1261
    1268    48073  97 pick_next_task_rt              sched_rt.c           884
       0    45181 100 sched_info_dequeued            sched_stats.h        177
       0       15 100 sched_move_task                sched.c              8700
       0       15 100 sched_move_task                sched.c              8690
   53167    33217  38 schedule                       sched.c              4457
       0    80208 100 sched_info_switch              sched_stats.h        270
   30585    49631  61 context_switch                 sched.c              2619

# cat /debug/tracing/profile_likely | awk '{ if ($3 > 25) print $0; }'
   39900    36577  47 pick_next_task                 sched.c              4397
   20824    15233  42 switch_mm                      mmu_context_64.h     18
       0        7 100 __cancel_work_timer            workqueue.c          560
     617    66484  99 clocksource_adjust             timekeeping.c        456
       0   346340 100 audit_syscall_exit             auditsc.c            1570
      38   347350  99 audit_get_context              auditsc.c            732
       0   345244 100 audit_syscall_entry            auditsc.c            1541
      38     1017  96 audit_free                     auditsc.c            1446
       0     1090 100 audit_alloc                    auditsc.c            862
    2618     1090  29 audit_alloc                    auditsc.c            858
       0        6 100 move_masked_irq                migration.c          9
       1      198  99 probe_sched_wakeup             trace_sched_switch.c 58
       2        2  50 probe_wakeup                   trace_sched_wakeup.c 227
       0        2 100 probe_wakeup_sched_switch      trace_sched_wakeup.c 144
    4514     2090  31 __grab_cache_page              filemap.c            2149
   12882   228786  94 mapping_unevictable            pagemap.h            50
       4       11  73 __flush_cpu_slab               slub.c               1466
  627757   330451  34 slab_free                      slub.c               1731
    2959    61245  95 dentry_lru_del_init            dcache.c             153
     946     1217  56 load_elf_binary                binfmt_elf.c         904
     102       82  44 disk_put_part                  genhd.h              206
       1        1  50 dst_gc_task                    dst.c                82
       0       19 100 tcp_mss_split_point            tcp_output.c         1126

As you can see by the above, there's a bit of work to do in rethinking
the use of some unlikelys and likelys. Note: the unlikely case had 71 hits
that were more than 25%.

Note:  After submitting my first version of this patch, Andrew Morton
  showed me a version written by Daniel Walker, where I picked up
  the following ideas from:

  1)  Using __builtin_constant_p to avoid profiling fixed values.
  2)  Using __FILE__ instead of instruction pointers.
  3)  Using the preprocessor to stop all profiling of likely
       annotations from vsyscall_64.c.

Thanks to Andrew Morton, Arjan van de Ven, Theodore Tso and Ingo Molnar
for their feed back on this patch.

(*) Not ever unlikely is recorded, those that are used by vsyscalls
 (a few of them) had to have profiling disabled.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-12 11:52:02 +01:00
Ingo Molnar
cb9382e5a9 Merge branches 'tracing/fastboot', 'tracing/function-return-tracer' and 'tracing/ring-buffer' into tracing/core 2008-11-12 11:50:51 +01:00