- 02 6月, 2009 1 次提交
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由 Steven Rostedt 提交于
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: NSteven Rostedt <rostedt@goodmis.org>
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- 18 5月, 2009 1 次提交
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由 Ming Lei 提交于
return zero should be correct, so fix it. [ Impact: eliminate incorrect syslog message ] Signed-off-by: NMing Lei <tom.leiming@gmail.com> Acked-by: NFrederic Weisbecker <fweisbec@gmail.com> Acked-by: NLi Zefan <lizf@cn.fujitsu.com> Cc: rostedt@goodmis.org LKML-Reference: <1242545498-7285-1-git-send-email-tom.leiming@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 17 4月, 2009 1 次提交
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由 Steven Rostedt 提交于
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: NSteven Rostedt <rostedt@goodmis.org>
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- 15 4月, 2009 1 次提交
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由 Steven Rostedt 提交于
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: NSteven Rostedt <rostedt@goodmis.org>
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- 07 4月, 2009 2 次提交
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由 Steven Rostedt 提交于
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: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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由 Frederic Weisbecker 提交于
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: NIngo Molnar <mingo@elte.hu> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1238109938-11840-1-git-send-email-fweisbec@gmail.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 01 4月, 2009 1 次提交
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 30 3月, 2009 1 次提交
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由 Uwe Kleine-Koenig 提交于
Signed-off-by: NUwe Kleine-Koenig <ukleinek@strlen.de> Signed-off-by: NJiri Kosina <jkosina@suse.cz>
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- 26 3月, 2009 4 次提交
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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由 Zhaolei 提交于
"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: NZhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
Ingo Molnar suggested clean ups for the profiling code. This patch makes those updates. Reported-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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- 25 3月, 2009 5 次提交
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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- 24 3月, 2009 5 次提交
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由 Lai Jiangshan 提交于
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: NLai 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: NIngo Molnar <mingo@elte.hu>
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由 Lai Jiangshan 提交于
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: NLai 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: NIngo Molnar <mingo@elte.hu>
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
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: NSteven Rostedt <srostedt@redhat.com>
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- 17 3月, 2009 1 次提交
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由 Frederic Weisbecker 提交于
Impact: fix a dynamic tracing failure Recently, the function and function graph tracers failed to use dynamic tracing after the following commit: fa9d13cf (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: NFrederic Weisbecker <fweisbec@gmail.com> Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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- 13 3月, 2009 4 次提交
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由 Lai Jiangshan 提交于
Impact: save memory The struct dyn_ftrace table is very large, this patch will save about 50%. Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <49BA2C9F.8020009@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Lai Jiangshan 提交于
Impact: cleanup VFS layer has tested the file mode, we do not need test it. Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <49BA2BAB.6010608@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Zhaolei 提交于
Do __ftrace_replace_code for !FTRACE_FL_CONVERTED rec will always fail, we should ignore this rec. Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com> Cc: "Steven Rostedt ;" <rostedt@goodmis.org> LKML-Reference: <49BA2472.4060206@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Zhaolei 提交于
If dyn_ftrace is freed before ftrace_release(), ftrace_release() will free it again and make ftrace_free_records wrong. Signed-off-by: NZhao Lei <zhaolei@cn.fujitsu.com> Cc: "Steven Rostedt ;" <rostedt@goodmis.org> LKML-Reference: <49BA23D9.1050900@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 06 3月, 2009 2 次提交
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由 KOSAKI Motohiro 提交于
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: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: NLai Jiangshan <laijs@cn.fujitsu.com> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <20090306151155.0778.A69D9226@jp.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Steven Rostedt 提交于
Impact: cleanup All file_operations structures should be constant. No one is going to change them. Reported-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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- 21 2月, 2009 2 次提交
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由 Steven Rostedt 提交于
Impact: added precaution on failure detection Break out of the modifying loop as soon as a failure is detected. This is just an added precaution found by code review and was not found by any bug chasing. Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
This patch creates the weak functions: ftrace_arch_code_modify_prepare and ftrace_arch_code_modify_post_process that are called before and after the stop machine is called to modify the kernel text. If the arch needs to do pre or post processing, it only needs to define these functions. [ Update: Ingo Molnar suggested using the name ftrace_arch_code_modify_* over using ftrace_arch_modify_* ] Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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- 20 2月, 2009 1 次提交
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由 Frederic Weisbecker 提交于
Impact: trace only functions matching a pattern The set_graph_function file let one to trace only one or several chosen functions and follow all their code flow. Currently, only a constant function name is allowed so this patch allows the ftrace_regex functions: - matches all functions that end with "name": echo *name > set_graph_function - matches all functions that begin with "name": echo name* > set_graph_function - matches all functions that contains "name": echo *name* > set_graph_function Example: echo mutex* > set_graph_function 0) | mutex_lock_nested() { 0) 0.563 us | __might_sleep(); 0) 2.072 us | } 0) | mutex_unlock() { 0) 1.036 us | __mutex_unlock_slowpath(); 0) 2.433 us | } 0) | mutex_unlock() { 0) 0.691 us | __mutex_unlock_slowpath(); 0) 1.787 us | } 0) | mutex_lock_interruptible_nested() { 0) 0.548 us | __might_sleep(); 0) 1.945 us | } Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 18 2月, 2009 3 次提交
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由 Frederic Weisbecker 提交于
When the function graph tracer is activated, it iterates over the task_list to allocate a stack to store the return addresses. But the per cpu idle tasks are not iterated by using do_each_thread / while_each_thread. So we have to iterate on them manually. This fixes somes weirdness in the traces and many losses of traces. Examples on two cpus: 0) Xorg-4287 | 2.906 us | } 0) Xorg-4287 | 3.965 us | } 0) Xorg-4287 | 5.302 us | } ------------------------------------------ 0) Xorg-4287 => <idle>-0 ------------------------------------------ 0) <idle>-0 | 2.861 us | } 0) <idle>-0 | 0.526 us | set_normalized_timespec(); 0) <idle>-0 | 7.201 us | } 0) <idle>-0 | 8.214 us | } 0) <idle>-0 | | clockevents_program_event() { 0) <idle>-0 | | lapic_next_event() { 0) <idle>-0 | 0.510 us | native_apic_mem_write(); 0) <idle>-0 | 1.546 us | } 0) <idle>-0 | 2.583 us | } 0) <idle>-0 | + 12.435 us | } 0) <idle>-0 | + 13.470 us | } 0) <idle>-0 | 0.608 us | _spin_unlock_irqrestore(); 0) <idle>-0 | + 23.270 us | } 0) <idle>-0 | + 24.336 us | } 0) <idle>-0 | + 25.417 us | } 0) <idle>-0 | 0.593 us | _spin_unlock(); 0) <idle>-0 | + 41.869 us | } 0) <idle>-0 | + 42.906 us | } 0) <idle>-0 | + 95.035 us | } 0) <idle>-0 | 0.540 us | menu_reflect(); 0) <idle>-0 | ! 100.404 us | } 0) <idle>-0 | 0.564 us | mce_idle_callback(); 0) <idle>-0 | | enter_idle() { 0) <idle>-0 | 0.526 us | mce_idle_callback(); 0) <idle>-0 | 1.757 us | } 0) <idle>-0 | | cpuidle_idle_call() { 0) <idle>-0 | | menu_select() { 0) <idle>-0 | 0.525 us | pm_qos_requirement(); 0) <idle>-0 | 0.518 us | tick_nohz_get_sleep_length(); 0) <idle>-0 | 2.621 us | } [...] 1) <idle>-0 | 0.518 us | touch_softlockup_watchdog(); 1) <idle>-0 | + 14.355 us | } 1) <idle>-0 | + 22.840 us | } 1) <idle>-0 | + 25.949 us | } 1) <idle>-0 | | handle_irq() { 1) <idle>-0 | 0.511 us | irq_to_desc(); 1) <idle>-0 | | handle_edge_irq() { 1) <idle>-0 | 0.638 us | _spin_lock(); 1) <idle>-0 | | ack_apic_edge() { 1) <idle>-0 | 0.510 us | irq_to_desc(); 1) <idle>-0 | | move_native_irq() { 1) <idle>-0 | 0.510 us | irq_to_desc(); 1) <idle>-0 | 1.532 us | } 1) <idle>-0 | 0.511 us | native_apic_mem_write(); ------------------------------------------ 1) <idle>-0 => cat-5073 ------------------------------------------ 1) cat-5073 | 3.731 us | } 1) cat-5073 | | run_local_timers() { 1) cat-5073 | 0.533 us | hrtimer_run_queues(); 1) cat-5073 | | raise_softirq() { 1) cat-5073 | | __raise_softirq_irqoff() { 1) cat-5073 | | /* nr: 1 */ 1) cat-5073 | 2.718 us | } 1) cat-5073 | 3.814 us | } Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Steven Rostedt 提交于
Impact: clean up Ingo Molnar did not like the _hook naming convention used by the select function tracer. Luis Claudio R. Goncalves suggested using the "_probe" extension. This patch implements the change of calling the functions and variables "_hook" and replacing them with "_probe". Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
Ingo Molnar pointed out some coding style issues with the recent ftrace updates. This patch cleans them up. Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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- 17 2月, 2009 5 次提交
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由 Ingo Molnar 提交于
Impact: build fix Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Steven Rostedt 提交于
This patch adds a call back for the tracers that have hooks to selected functions. This allows the tracer to show better output in the set_ftrace_filter file. Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
This patch adds output to show what functions have tracer hooks attached to them. # echo 'sys_open:traceon:4' > /debug/tracing/set_ftrace_filter # cat set_ftrace_filter #### all functions enabled #### sys_open:ftrace_traceon:0000000000000004 # echo 'do_fork:traceoff:' > set_ftrace_filter # cat set_ftrace_filter #### all functions enabled #### sys_open:ftrace_traceon:0000000000000002 do_fork:ftrace_traceoff:ffffffffffffffff Note the 4 changed to a 2. This is because The code was executed twice since the traceoff was added. If a cat is done again: #### all functions enabled #### sys_open:ftrace_traceon do_fork:ftrace_traceoff:ffffffffffffffff The number disappears. That is because it will not print a NULL. Callbacks to allow the tracer to pretty print will be implemented soon. Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
Impact: new feature Currently, the function tracer only gives you an ability to hook a tracer to all functions being traced. The dynamic function trace allows you to pick and choose which of those functions will be traced, but all functions being traced will call all tracers that registered with the function tracer. This patch adds a new feature that allows a tracer to hook to specific functions, even when all functions are being traced. It allows for different functions to call different tracer hooks. The way this is accomplished is by a special function that will hook to the function tracer and will set up a hash table knowing which tracer hook to call with which function. This is the most general and easiest method to accomplish this. Later, an arch may choose to supply their own method in changing the mcount call of a function to call a different tracer. But that will be an exercise for the future. To register a function: struct ftrace_hook_ops { void (*func)(unsigned long ip, unsigned long parent_ip, void **data); int (*callback)(unsigned long ip, void **data); void (*free)(void **data); }; int register_ftrace_function_hook(char *glob, struct ftrace_hook_ops *ops, void *data); glob is a simple glob to search for the functions to hook. ops is a pointer to the operations (listed below) data is the default data to be passed to the hook functions when traced ops: func is the hook function to call when the functions are traced callback is a callback function that is called when setting up the hash. That is, if the tracer needs to do something special for each function, that is being traced, and wants to give each function its own data. The address of the entry data is passed to this callback, so that the callback may wish to update the entry to whatever it would like. free is a callback for when the entry is freed. In case the tracer allocated any data, it is give the chance to free it. To unregister we have three functions: void unregister_ftrace_function_hook(char *glob, struct ftrace_hook_ops *ops, void *data) This will unregister all hooks that match glob, point to ops, and have its data matching data. (note, if glob is NULL, blank or '*', all functions will be tested). void unregister_ftrace_function_hook_func(char *glob, struct ftrace_hook_ops *ops) This will unregister all functions matching glob that has an entry pointing to ops. void unregister_ftrace_function_hook_all(char *glob) This simply unregisters all funcs. Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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由 Steven Rostedt 提交于
Impact: clean up Now that ftrace_lock is a mutex, there is no reason to have three different mutexes protecting similar data. All the mutex paths are not in hot paths, so having a mutex to cover more data is not a problem. This patch removes the ftrace_sysctl_lock and ftrace_start_lock and uses the ftrace_lock to protect the locations that were protected by these locks. By doing so, this change also removes some of the lock nesting that was taking place. There are still more mutexes in ftrace.c that can probably be consolidated, but they can be dealt with later. We need to be careful about the way the locks are nested, and by consolidating, we can cause a recursive deadlock. Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
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