Commit Graph

182 Commits

Author SHA1 Message Date
Ingo Molnar
ed011b22ce Merge commit 'v2.6.31-rc9' into tracing/core
Merge reason: move from -rc5 to -rc9.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-06 06:11:42 +02:00
Jiri Olsa
eda1e32855 tracing: handle broken names in ftrace filter
If one filter item (for set_ftrace_filter and set_ftrace_notrace) is being
setup by more than 1 consecutive writes (FTRACE_ITER_CONT flag), it won't
be handled corretly.

I used following program to test/verify:

[snip]
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>

int main(int argc, char **argv)
{
        int fd, i;
        char *file = argv[1];

        if (-1 == (fd = open(file, O_WRONLY))) {
                perror("open failed");
                return -1;
        }

        for(i = 0; i < (argc - 2); i++) {
                int len = strlen(argv[2+i]);
                int cnt, off = 0;

                while(len) {
                        cnt = write(fd, argv[2+i] + off, len);
                        len -= cnt;
                        off += cnt;
                }
        }

        close(fd);
        return 0;
}
[snip]

before change:
sh-4.0# echo > ./set_ftrace_filter
sh-4.0# /test ./set_ftrace_filter "sys" "_open "
sh-4.0# cat ./set_ftrace_filter
#### all functions enabled ####
sh-4.0#

after change:
sh-4.0# echo > ./set_ftrace_notrace
sh-4.0# test ./set_ftrace_notrace "sys" "_open "
sh-4.0# cat ./set_ftrace_notrace
sys_open
sh-4.0#

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <20090811152904.GA26065@jolsa.lab.eng.brq.redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-18 20:39:48 -04:00
Li Zefan
3be04b471b ftrace: Simplify seqfile code
Use seq_release_private().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A891AAB.8090701@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-17 11:25:10 +02:00
Ingo Molnar
89034bc2c7 Merge branch 'linus' into tracing/core
Conflicts:
	kernel/trace/trace_events_filter.c

We use the tracing/core version.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-11 14:19:09 +02:00
Steven Rostedt
8650ae32ef tracing: only truncate ftrace files when O_TRUNC is set
The current code will truncate the ftrace files contents if O_APPEND
is not set and the file is opened in write mode. This is incorrect.
It should only truncate the file if O_TRUNC is set. Otherwise
if one of these files is opened by a C program with fopen "r+",
it will incorrectly truncate the file.

Reported-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-07-23 10:07:18 -04:00
Li Zefan
87827111a5 function-graph: Fix seqfile memory leak
Every time we cat set_graph_function, we leak memory allocated
by seq_open().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A67D907.2010500@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-07-23 09:53:23 -04:00
jolsa@redhat.com
566b0aaf79 tracing: Remove unused fields/variables
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: rostedt@goodmis.org
LKML-Reference: <1247773468-11594-2-git-send-email-jolsa@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-18 12:21:16 +02:00
Ingo Molnar
45bceffc30 Merge branch 'linus' into tracing/core
Merge reason: tracing/core was on an older, pre-rc1 base.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-18 12:20:01 +02:00
Xiao Guangrong
6f2f3cf00e tracing/function: Cleanup for function tracer
We can directly use %pf input format instead of kallsyms_lookup()
and %s input format

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-07-17 01:45:51 -04:00
Xiao Guangrong
64fbcd1628 tracing/function: Simplify __ftrace_replace_code()
Rewrite the __ftrace_replace_code() function, simplify it, but don't
change the code's logic.

First, we get the state we want to set, if the record has the same
state, then do nothing, otherwise enable/disable it.

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-07-17 00:37:53 -04:00
Steven Rostedt
6ab5d668b1 tracing/function-profiler: do not free per cpu variable stat
The per cpu variable stat is freeded if we fail to allocate a name
on start up. This was due to stat at first being allocated in the
initial design. But since then, it has become a static per cpu variable
but the free on error was not removed.

Also added __init annotation to the function that this is in.

[ Impact: prevent possible memory corruption on low mem at boot up ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-13 11:01:10 +02:00
Li Zefan
a32c7765e2 tracing: Fix stack tracer sysctl handling
This made my machine completely frozen:

  # echo 1 > /proc/sys/kernel/stack_tracer_enabled
  # echo 2 > /proc/sys/kernel/stack_tracer_enabled

The cause is register_ftrace_function() was called twice.

Also fix ftrace_enabled sysctl, though seems nothing bad happened
as I tested it.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A448D17.9010305@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-26 20:48:39 +02:00
Li Zefan
0296e4254f ftrace: Fix the output of profile
The first entry of the ftrace profile was always skipped when
reading trace_stat/functionX.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A443D59.4080307@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-26 09:25:42 +02:00
Li Zefan
d82d62444f ftrace: Fix t_hash_start()
When the output of set_ftrace_filter is larger than PAGE_SIZE,
t_hash_start() will be called the 2nd time, and then we start
from the head of a hlist, which is wrong and causes some entries
to be outputed twice.

The worse is, if the hlist is large enough, reading set_ftrace_filter
won't stop but in a dead loop.

Reviewed-by: Liming Wang <liming.wang@windriver.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A41876E.2060407@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-24 11:02:53 +02:00
Li Zefan
694ce0a544 ftrace: Don't manipulate @pos in t_start()
It's rather confusing that in t_start(), in some cases @pos is
incremented, and in some cases it's decremented and then incremented.

This patch rewrites t_start() in a much more general way.

Thus we fix a bug that if ftrace_filtered == 1, functions have tracer
hooks won't be printed, because the branch is always unreachable:

static void *t_start(...)
{
	...
	if (!p)
		return t_hash_start(m, pos);
	return p;
}

Before:
  # echo 'sys_open' > /mnt/tracing/set_ftrace_filter
  # echo 'sys_write:traceon:4' >> /mnt/tracing/set_ftrace_filter
  sys_open

After:
  # echo 'sys_open' > /mnt/tracing/set_ftrace_filter
  # echo 'sys_write:traceon:4' >> /mnt/tracing/set_ftrace_filter
  sys_open
  sys_write:traceon:count=4

Reviewed-by: Liming Wang <liming.wang@windriver.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A41874B.4090507@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-24 11:02:53 +02:00
Li Zefan
85951842a1 ftrace: Don't increment @pos in g_start()
It's wrong to increment @pos in g_start(). It causes some entries
lost when reading set_graph_function, if the output of the file
is larger than PAGE_SIZE.

Reviewed-by: Liming Wang <liming.wang@windriver.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A418738.7090401@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-24 11:02:52 +02:00
Frederic Weisbecker
9ea1a153a4 tracing/urgent: warn in case of ftrace_start_up inbalance
Prevent from further ftrace_start_up inbalances so that we avoid
future nop patching omissions with dynamic ftrace.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
2009-06-20 06:52:21 +02:00
Linus Torvalds
991ec02cdc Merge branch 'tracing-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  function-graph: always initialize task ret_stack
  function-graph: move initialization of new tasks up in fork
  function-graph: add memory barriers for accessing task's ret_stack
  function-graph: enable the stack after initialization of other variables
  function-graph: only allocate init tasks if it was not already done

Manually fix trivial conflict in kernel/trace/ftrace.c
2009-06-10 19:58:10 -07:00
Steven Rostedt
84047e360a function-graph: always initialize task ret_stack
On creating a new task while running the function graph tracer, if
we fail to allocate the ret_stack, and then fail the fork, the
code will free the parent ret_stack. This is because the child
duplicated the parent and currently points to the parent's ret_stack.

This patch always initializes the task's ret_stack to NULL.

[ Impact: prevent crash of parent on low memory during fork ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-02 16:51:55 -04:00
Steven Rostedt
26c01624a2 function-graph: add memory barriers for accessing task's ret_stack
The code that handles the tasks ret_stack allocation for every task
assumes that only an interrupt can cause issues (even though interrupts
are disabled).

In reality, the code is allocating the ret_stack for tasks that may be
running on other CPUs and there are not efficient memory barriers to
handle this case.

[ Impact: prevent crash due to using of uninitialized ret_stack variables ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-02 14:42:17 -04:00
Steven Rostedt
82310a3272 function-graph: enable the stack after initialization of other variables
The function graph tracer checks if the task_struct has ret_stack defined
to know if it is OK or not to use it. The initialization is done for
all tasks by one process, but the idle tasks use the same initialization
used by new tasks.

If an interrupt happens on an idle task that just had the ret_stack
created, but before the rest of the initialization took place, then
we can corrupt the return address of the functions.

This patch moves the setting of the task_struct's ret_stack to after
the other variables have been initialized.

[ Impact: prevent kernel panic on idle task when starting function graph ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-02 14:41:50 -04:00
Steven Rostedt
179c498ae2 function-graph: only allocate init tasks if it was not already done
When the function graph tracer is enabled, it calls the initialization
needed for the init tasks that would be called on all created tasks.

The problem is that this is called every time the function graph tracer
is enabled, and the ret_stack is allocated for the idle tasks each time.
Thus, the old ret_stack is lost and a memory leak is created.

This is also dangerous because if an interrupt happened on another CPU
with the init task and the ret_stack is replaced, we then lose all the
return pointers for the interrupt, and a crash would take place.

[ Impact: fix memory leak and possible crash due to race ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-02 12:03:19 -04:00
Steven Rostedt
0f6ce3de4e ftrace: do not profile functions when disabled
A race was found that if one were to enable and disable the function
profiler repeatedly, then the system can panic. This was because a profiled
function may be preempted just before disabling interrupts. While
the profiler is disabled and then reenabled, the preempted function
could start again, and access the hash as it is being initialized.

This just adds a check in the irq disabled part to check if the profiler
is enabled, and if it is not then it will just exit.

When the system is disabled, the profile_enabled variable is cleared
before calling the unregistering of the function profiler. This
unregistering calls stop machine which also acts as a synchronize schedule.

[ Impact: fix panic in enabling/disabling function profiler ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-01 23:26:23 -04:00
Steven Rostedt
2af15d6a44 ftrace: add kernel command line function filtering
When using ftrace=function on the command line to trace functions
on boot up, one can not filter out functions that are commonly called.

This patch adds two new ftrace command line commands.

  ftrace_notrace=function-list
  ftrace_filter=function-list

Where function-list is a comma separated list of functions to filter.
The ftrace_notrace will make the functions listed not be included
in the function tracing, and ftrace_filter will only trace the functions
listed.

These two act the same as the debugfs/tracing/set_ftrace_notrace and
debugfs/tracing/set_ftrace_filter respectively.

The simple glob expressions that are allowed by the filter files can also
be used by the command line interface.

	ftrace_notrace=rcu*,*lock,*spin*

Will not trace any function that starts with rcu, ends with lock, or has
the word spin in it.

Note, if the self tests are enabled, they may interfere with the filtering
set by the command lines.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-01 23:23:10 -04:00
Ming Lei
24ed0c4bfc tracing: fix check for return value of register_module_notifier
return zero should be correct, so fix it.

[ Impact: eliminate incorrect syslog message ]

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: rostedt@goodmis.org
LKML-Reference: <1242545498-7285-1-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-18 10:24:13 +02:00
Steven Rostedt
93eb677d74 ftrace: use module notifier for function tracer
The hooks in the module code for the function tracer must be called
before any of that module code runs. The function tracer hooks
modify the module (replacing calls to mcount to nops). If the code
is executed while the change occurs, then the CPU can take a GPF.

To handle the above with a bit of paranoia, I originally implemented
the hooks as calls directly from the module code.

After examining the notifier calls, it looks as though the start up
notify is called before any of the module's code is executed. This makes
the use of the notify safe with ftrace.

Only the startup notify is required to be "safe". The shutdown simply
removes the entries from the ftrace function list, and does not modify
any code.

This change has another benefit. It removes a issue with a reverse dependency
in the mutexes of ftrace_lock and module_mutex.

[ Impact: fix lock dependency bug, cleanup ]

Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-17 16:59:15 +02:00
Steven Rostedt
ad8d75fff8 tracing/events: move trace point headers into include/trace/events
Impact: clean up

Create a sub directory in include/trace called events to keep the
trace point headers in their own separate directory. Only headers that
declare trace points should be defined in this directory.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-14 22:05:43 -04:00
Steven Rostedt
597af81537 function-graph: use int instead of atomic for ftrace_graph_active
Impact: cleanup

The variable ftrace_graph_active is only modified under the
ftrace_lock mutex, thus an atomic is not necessary for modification.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-07 14:43:08 +02:00
Frederic Weisbecker
5452af664f tracing/ftrace: factorize the tracing files creation
Impact: cleanup

Most of the tracing files creation follow the same pattern:

ret = debugfs_create_file(...)
if (!ret)
	pr_warning("Couldn't create ... entry\n")

Unify it!

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1238109938-11840-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-07 14:43:07 +02:00
Ingo Molnar
93776a8ec7 Merge branch 'linus' into tracing/core
Merge reason: update to upstream tracing facilities

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-07 13:47:45 +02:00
Steven Rostedt
2aad1b76e6 function-graph: allow unregistering twice
Impact: fix to permanent disabling of function graph tracer

There should be nothing to prevent a tracer from unregistering a
function graph callback more than once. This can simplify error paths.

But currently, the counter does not account for mulitple unregistering
of the function graph callback. If it happens, the function graph
tracer will be permanently disabled.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-01 14:47:42 +02:00
Steven Rostedt
34886c8bc5 tracing: add average time in function to function profiler
Show the average time in the function (Time / Hit)

  Function                               Hit    Time            Avg
  --------                               ---    ----            ---
  mwait_idle                              51    140326.6 us     2751.503 us
  smp_apic_timer_interrupt                47    3517.735 us     74.845 us
  schedule                                10    2738.754 us     273.875 us
  __schedule                              10    2732.857 us     273.285 us
  hrtimer_interrupt                       47    1896.104 us     40.342 us
  irq_exit                                56    1711.833 us     30.568 us
  __run_hrtimer                           47    1315.589 us     27.991 us
  tick_sched_timer                        47    1138.690 us     24.227 us
  do_softirq                              56    1116.829 us     19.943 us
  __do_softirq                            56    1066.932 us     19.052 us
  do_IRQ                                   9    926.153 us      102.905 us

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-25 21:03:36 -04:00
Steven Rostedt
318e0a73c9 tracing: remove on the fly allocator from function profiler
Impact: safer code

The on the fly allocator for the function profiler was to save
memory. But at the expense of stability. Although it survived several
tests, allocating from the function tracer is just too risky, just
to save space.

This patch removes the allocator and simply allocates enough entries
at start up.

Each function gets a profiling structure of 40 bytes. With an average
of 20K functions, and this is for each CPU, we have 800K per online
CPU. This is not too bad, at least for non-embedded.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-25 21:03:17 -04:00
Zhaolei
2a4efa4245 ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release()
"Because when we call ftrace_free_rec we change the rec->ip to point to the
  next record in the chain. Something is very wrong if rec->ip >= s &&
  rec->ip < e and the record is already free."

 "Note, use FTRACE_WARN_ON() macro. This way it shuts down ftrace if it is
  hit and helps to avoid further damage later."
                   -- Steven Rostedt <rostedt@goodmis.org>

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-25 17:45:36 -04:00
Steven Rostedt
fb9fb015e9 tracing: clean up tracing profiler
Ingo Molnar suggested clean ups for the profiling code. This patch
makes those updates.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-25 13:26:41 -04:00
Steven Rostedt
a2a16d6a31 function-graph: add option to calculate graph time or not
graph time is the time that a function is executing another function.
Thus if function A calls B, if graph-time is set, then the time for
A includes B. This is the default behavior. But if graph-time is off,
then the time spent executing B is subtracted from A.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-24 23:41:11 -04:00
Steven Rostedt
cafb168a1c tracing: make the function profiler per cpu
Impact: speed enhancement

By making the function profiler record in per cpu data we not only
get better readings, avoid races, we also do not have to take any
locks.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-24 23:41:10 -04:00
Steven Rostedt
0706f1c48c tracing: adding function timings to function profiler
If the function graph trace is enabled, the function profiler will
use it to take the timing of the functions.

 cat /debug/tracing/trace_stat/functions

  Function                               Hit    Time
  --------                               ---    ----
  mwait_idle                             127    183028.4 us
  schedule                                26    151997.7 us
  __schedule                              31    151975.1 us
  sys_wait4                                2    74080.53 us
  do_wait                                  2    74077.80 us
  sys_newlstat                           138    39929.16 us
  do_path_lookup                         179    39845.79 us
  vfs_lstat_fd                           138    39761.97 us
  user_path_at                           153    39469.58 us
  path_walk                              179    39435.76 us
  __link_path_walk                       189    39143.73 us
[...]

Note the times are skewed due to the function graph tracer not taking
into account schedules.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-24 23:41:09 -04:00
Steven Rostedt
493762fc53 tracing: move function profiler data out of function struct
Impact: reduce size of memory in function profiler

The function profiler originally introduces its counters into the
function records itself. There is 20 thousand different functions on
a normal system, and that is adding 20 thousand counters for profiling
event when not needed.

A normal run of the profiler yields only a couple of thousand functions
executed, depending on what is being profiled. This means we have around
18 thousand useless counters.

This patch rectifies this by moving the data out of the function
records used by dynamic ftrace. Data is preallocated to hold the functions
when the profiling begins. Checks are made during profiling to see if
more recorcds should be allocated, and they are allocated if it is safe
to do so.

This also removes the dependency from using dynamic ftrace, and also
removes the overhead by having it enabled.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-24 23:41:06 -04:00
Steven Rostedt
bac429f037 tracing: add function profiler
Impact: new profiling feature

This patch adds a function profiler. In debugfs/tracing/ two new
files are created.

  function_profile_enabled  - to enable or disable profiling

  trace_stat/functions   - the profiled functions.

For example:

  echo 1 > /debugfs/tracing/function_profile_enabled
  ./hackbench 50
  echo 0 > /debugfs/tracing/function_profile_enabled

yields:

  cat /debugfs/tracing/trace_stat/functions

  Function                               Hit
  --------                               ---
  _spin_lock                        10106442
  _spin_unlock                      10097492
  kfree                              6013704
  _spin_unlock_irqrestore            4423941
  _spin_lock_irqsave                 4406825
  __phys_addr                        4181686
  __slab_free                        4038222
  dput                               4030130
  path_put                           4023387
  unroll_tree_refs                   4019532
[...]

The most hit functions are listed first. Functions that are not
hit are not listed.

This feature depends on and uses dynamic function tracing. When the
function profiling is disabled, no overhead occurs. But it still
takes up around 300KB to hold the data, thus it is not recomended
to keep it enabled for systems low on memory.

When a '1' is echoed into the function_profile_enabled file, the
counters for is function is reset back to zero. Thus you can see what
functions are hit most by different programs.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-24 23:40:00 -04:00
Lai Jiangshan
ee000b7f9f tracing: use union for multi-usages field
Impact: cleanup

struct dyn_ftrace::ip has different usages in his lifecycle,
we use union for it. And also for struct dyn_ftrace::flags.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C871BE.3080405@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-24 16:43:12 +01:00
Lai Jiangshan
cc59c9e8d0 ftrace: show virtual PID
Impact: fix PID output under namespaces

When current namespace is not the global namespace,
pid read from set_ftrace_pid is no correct.

 # ~/newpid_namespace_run bash
 # echo $$
 1
 # echo 1 > set_ftrace_pid
 # cat set_ftrace_pid
 3756

Since we write virtual PID to set_ftrace_pid, we need get
virtual PID when we read it.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C84D65.9050606@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-24 16:42:49 +01:00
Steven Rostedt
be6f164a02 function-graph: add option for include sleep times
Impact: give user a choice to show times spent while sleeping

The user may want to see the time a function spent sleeping.
This patch adds the trace option "sleep-time" to allow that.
The "sleep-time" option is default on.

 echo sleep-time > /debug/tracing/trace_options

produces:

 ------------------------------------------
 2)  avahi-d-3428  =>    <idle>-0
 ------------------------------------------

 2)               |      finish_task_switch() {
 2)   0.621 us    |        _spin_unlock_irq();
 2)   2.202 us    |      }
 2) ! 1002.197 us |    }
 2) ! 1003.521 us |  }

where as,

 echo nosleep-time > /debug/tracing/trace_options

produces:

 0)    <idle>-0    =>  yum-upd-3416
 ------------------------------------------

 0)               |              finish_task_switch() {
 0)   0.643 us    |                _spin_unlock_irq();
 0)   2.342 us    |              }
 0) + 41.302 us   |            }
 0) + 42.453 us   |          }

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-24 11:06:24 -04:00
Steven Rostedt
8aef2d2856 function-graph: ignore times across schedule
Impact: more accurate timings

The current method of function graph tracing does not take into
account the time spent when a task is not running. This shows functions
that call schedule have increased costs:

 3) + 18.664 us   |      }
 ------------------------------------------
 3)    <idle>-0    =>  kblockd-123
 ------------------------------------------

 3)               |      finish_task_switch() {
 3)   1.441 us    |        _spin_unlock_irq();
 3)   3.966 us    |      }
 3) ! 2959.433 us |    }
 3) ! 2961.465 us |  }

This patch uses the tracepoint in the scheduling context switch to
account for time that has elapsed while a task is scheduled out.
Now we see:

 ------------------------------------------
 3)    <idle>-0    =>  edac-po-1067
 ------------------------------------------

 3)               |      finish_task_switch() {
 3)   0.685 us    |        _spin_unlock_irq();
 3)   2.331 us    |      }
 3) + 41.439 us   |    }
 3) + 42.663 us   |  }

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-24 09:33:30 -04:00
Steven Rostedt
05ce5818ad function-graph: prevent more than one tracer registering
Impact: prevent crash due to multiple function graph tracers

The function graph tracer can currently only handle a single tracer
being registered. If another tracer registers with the function
graph tracer it can crash the system.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-24 09:32:52 -04:00
Frederic Weisbecker
03303549b1 tracing/ftrace: fix the check on nopped sites
Impact: fix a dynamic tracing failure

Recently, the function and function graph tracers failed to use dynamic
tracing after the following commit:

fa9d13cf13
(ftrace: don't try to __ftrace_replace_code on !FTRACE_FL_CONVERTED rec)

The patch is right except a mistake on the check for the FTRACE_FL_CONVERTED
flag. The code patching is aborted in case of successfully nopped sites.
What we want is the opposite: ignore the callsites that haven't been nopped.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-16 22:15:36 -04:00
Lai Jiangshan
e94142a67f ftrace: remove struct list_head from struct dyn_ftrace
Impact: save memory

The struct dyn_ftrace table is very large, this patch will save
about 50%.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
LKML-Reference: <49BA2C9F.8020009@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-13 11:36:20 +01:00
Lai Jiangshan
850a80cfaa ftrace: use seq_read
Impact: cleanup

VFS layer has tested the file mode, we do not need test it.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
LKML-Reference: <49BA2BAB.6010608@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-13 11:35:31 +01:00
Zhaolei
fa9d13cf13 ftrace: don't try to __ftrace_replace_code on !FTRACE_FL_CONVERTED rec
Do __ftrace_replace_code for !FTRACE_FL_CONVERTED rec will always
fail, we should ignore this rec.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: "Steven Rostedt ;" <rostedt@goodmis.org>
LKML-Reference: <49BA2472.4060206@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-13 10:25:06 +01:00
Zhaolei
b00f0b6dc1 ftrace: avoid double-free of dyn_ftrace
If dyn_ftrace is freed before ftrace_release(), ftrace_release()
will free it again and make ftrace_free_records wrong.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: "Steven Rostedt ;" <rostedt@goodmis.org>
LKML-Reference: <49BA23D9.1050900@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-13 10:25:06 +01:00