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2012-02-13ftrace: sched_switch plugin is deprecatedGeunsik Lim1-3/+3
Actually, sched_switch function tracer is merged into wakeup/wakeup_rt Update 'mini-HOWTO' for ftrace(Kernel function tracer). If we want to trace "sched:sched_switch" to trace sched_switch func, We may utilize event option.(e.g: trace-cmd list -e | grep sched) This patch is based on Linux-3.3.rc2-SMP-PREEMPT Link: http://lkml.kernel.org/r/1328695537-15081-1-git-send-email-geunsik.lim@gmail.com Cc: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Geunsik Lim <geunsik.lim@samsung.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-01-08Merge branch 'for-linus2' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs * 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (165 commits) reiserfs: Properly display mount options in /proc/mounts vfs: prevent remount read-only if pending removes vfs: count unlinked inodes vfs: protect remounting superblock read-only vfs: keep list of mounts for each superblock vfs: switch ->show_options() to struct dentry * vfs: switch ->show_path() to struct dentry * vfs: switch ->show_devname() to struct dentry * vfs: switch ->show_stats to struct dentry * switch security_path_chmod() to struct path * vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb vfs: trim includes a bit switch mnt_namespace ->root to struct mount vfs: take /proc/*/mounts and friends to fs/proc_namespace.c vfs: opencode mntget() mnt_set_mountpoint() vfs: spread struct mount - remaining argument of next_mnt() vfs: move fsnotify junk to struct mount vfs: move mnt_devname vfs: move mnt_list to struct mount vfs: switch pnode.h macros to struct mount * ...
2012-01-06Merge branch 'perf-core-for-linus' of ↵Linus Torvalds1-26/+79
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (106 commits) perf kvm: Fix copy & paste error in description perf script: Kill script_spec__delete perf top: Fix a memory leak perf stat: Introduce get_ratio_color() helper perf session: Remove impossible condition check perf tools: Fix feature-bits rework fallout, remove unused variable perf script: Add generic perl handler to process events perf tools: Use for_each_set_bit() to iterate over feature flags perf tools: Unify handling of features when writing feature section perf report: Accept fifos as input file perf tools: Moving code in some files perf tools: Fix out-of-bound access to struct perf_session perf tools: Continue processing header on unknown features perf tools: Improve macros for struct feature_ops perf: builtin-record: Document and check that mmap_pages must be a power of two. perf: builtin-record: Provide advice if mmap'ing fails with EPERM. perf tools: Fix truncated annotation perf script: look up thread using tid instead of pid perf tools: Look up thread names for system wide profiling perf tools: Fix comm for processes with named threads ...
2012-01-03switch debugfs to umode_tAl Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-12-11trace: Allow ftrace_dump() to be called from modulesPaul E. McKenney1-0/+1
Add an EXPORT_SYMBOL_GPL() so that rcutorture can dump the trace buffer upon detection of an RCU error. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-11-17tracing: Add entries in buffer and total entries to default output headerSteven Rostedt1-25/+47
Knowing the number of event entries in the ring buffer compared to the total number that were written is useful information. The latency format gives this information and there's no reason that the default format does not. This information is now added to the default header, along with the number of online CPUs: # tracer: nop # # entries-in-buffer/entries-written: 159836/64690869 #P:4 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <idle>-0 [000] ...2 49.442971: local_touch_nmi <-cpu_idle <idle>-0 [000] d..2 49.442973: enter_idle <-cpu_idle <idle>-0 [000] d..2 49.442974: atomic_notifier_call_chain <-enter_idle <idle>-0 [000] d..2 49.442976: __atomic_notifier_call_chain <-atomic_notifier The above shows that the trace contains 159836 entries, but 64690869 were written. One could figure out that there were 64531033 entries that were dropped. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-17tracing: Add irq, preempt-count and need resched info to default trace outputSteven Rostedt1-4/+20
People keep asking how to get the preempt count, irq, and need resched info and we keep telling them to enable the latency format. Some developers think that traces without this info is completely useless, and for a lot of tasks it is useless. The first option was to enable the latency trace as the default format, but the header for the latency format is pretty useless for most tracers and it also does the timestamp in straight microseconds from the time the trace started. This is sometimes more difficult to read as the default trace is seconds from the start of boot up. Latency format: # tracer: nop # # nop latency trace v1.1.5 on 3.2.0-rc1-test+ # -------------------------------------------------------------------- # latency: 0 us, #159771/64234230, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: -0 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / migratio-6 0...2 41778231us+: rcu_note_context_switch <-__schedule migratio-6 0...2 41778233us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778235us+: rcu_sched_qs <-rcu_note_context_switch migratio-6 0d..2 41778236us+: rcu_preempt_qs <-rcu_note_context_switch migratio-6 0...2 41778238us : trace_rcu_utilization <-rcu_note_context_switch migratio-6 0...2 41778239us+: debug_lockdep_rcu_enabled <-__schedule default format: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | migration/0-6 [000] 50.025810: rcu_note_context_switch <-__schedule migration/0-6 [000] 50.025812: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025813: rcu_sched_qs <-rcu_note_context_switch migration/0-6 [000] 50.025815: rcu_preempt_qs <-rcu_note_context_switch migration/0-6 [000] 50.025817: trace_rcu_utilization <-rcu_note_context_switch migration/0-6 [000] 50.025818: debug_lockdep_rcu_enabled <-__schedule migration/0-6 [000] 50.025820: debug_lockdep_rcu_enabled <-__schedule The latency format header has latency information that is pretty meaningless for most tracers. Although some of the header is useful, and we can add that later to the default format as well. What is really useful with the latency format is the irqs-off, need-resched hard/softirq context and the preempt count. This commit adds the option irq-info which is on by default that adds this information: # tracer: nop # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <idle>-0 [000] d..2 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] d..2 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] d..2 49.309309: need_resched <-mwait_idle <idle>-0 [000] d..2 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] d..2 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] d..2 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] d..2 49.309315: need_resched <-mwait_idle If a user wants the old format, they can disable the 'irq-info' option: # tracer: nop # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <idle>-0 [000] 49.309305: cpuidle_get_driver <-cpuidle_idle_call <idle>-0 [000] 49.309307: mwait_idle <-cpu_idle <idle>-0 [000] 49.309309: need_resched <-mwait_idle <idle>-0 [000] 49.309310: test_ti_thread_flag <-need_resched <idle>-0 [000] 49.309312: trace_power_start.constprop.13 <-mwait_idle <idle>-0 [000] 49.309313: trace_cpu_idle <-mwait_idle <idle>-0 [000] 49.309315: need_resched <-mwait_idle Requested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-11-11Merge branch 'tip/perf/core' of ↵Ingo Molnar1-0/+15
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core
2011-11-07tracing/latency: Fix header output for latency tracersJiri Olsa1-0/+15
In case the the graph tracer (CONFIG_FUNCTION_GRAPH_TRACER) or even the function tracer (CONFIG_FUNCTION_TRACER) are not set, the latency tracers do not display proper latency header. The involved/fixed latency tracers are: wakeup_rt wakeup preemptirqsoff preemptoff irqsoff The patch adds proper handling of tracer configuration options for latency tracers, and displaying correct header info accordingly. * The current output (for wakeup tracer) with both graph and function tracers disabled is: # tracer: wakeup # <idle>-0 0d.h5 1us+: 0:120:R + [000] 7: 0:R watchdog/0 <idle>-0 0d.h5 3us+: ttwu_do_activate.clone.1 <-try_to_wake_up ... * The fixed output is: # tracer: wakeup # # wakeup latency trace v1.1.5 on 3.1.0-tip+ # -------------------------------------------------------------------- # latency: 55 us, #4/4, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) # ----------------- # | task: migration/0-6 (uid:0 nice:0 policy:1 rt_prio:99) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / cat-1129 0d..4 1us : 1129:120:R + [000] 6: 0:R migration/0 cat-1129 0d..4 2us+: ttwu_do_activate.clone.1 <-try_to_wake_up * The current output (for wakeup tracer) with only function tracer enabled is: # tracer: wakeup # cat-1140 0d..4 1us+: 1140:120:R + [000] 6: 0:R migration/0 cat-1140 0d..4 2us : ttwu_do_activate.clone.1 <-try_to_wake_up * The fixed output is: # tracer: wakeup # # wakeup latency trace v1.1.5 on 3.1.0-tip+ # -------------------------------------------------------------------- # latency: 207 us, #109/109, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) # ----------------- # | task: watchdog/1-12 (uid:0 nice:0 policy:1 rt_prio:99) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / delay # cmd pid ||||| time | caller # \ / ||||| \ | / <idle>-0 1d.h5 1us+: 0:120:R + [001] 12: 0:R watchdog/1 <idle>-0 1d.h5 3us : ttwu_do_activate.clone.1 <-try_to_wake_up Link: http://lkml.kernel.org/r/20111107150849.GE1807@m.brq.redhat.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-10-26Merge branch 'perf-core-for-linus' of ↵Linus Torvalds1-32/+149
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (121 commits) perf symbols: Increase symbol KSYM_NAME_LEN size perf hists browser: Refuse 'a' hotkey on non symbolic views perf ui browser: Use libslang to read keys perf tools: Fix tracing info recording perf hists browser: Elide DSO column when it is set to just one DSO, ditto for threads perf hists: Don't consider filtered entries when calculating column widths perf hists: Don't decay total_period for filtered entries perf hists browser: Honour symbol_conf.show_{nr_samples,total_period} perf hists browser: Do not exit on tab key with single event perf annotate browser: Don't change selection line when returning from callq perf tools: handle endianness of feature bitmap perf tools: Add prelink suggestion to dso update message perf script: Fix unknown feature comment perf hists browser: Apply the dso and thread filters when merging new batches perf hists: Move the dso and thread filters from hist_browser perf ui browser: Honour the xterm colors perf top tui: Give color hints just on the percentage, like on --stdio perf ui browser: Make the colors configurable and change the defaults perf tui: Remove unneeded call to newtCls on startup perf hists: Don't format the percentage on hist_entry__snprintf ... Fix up conflicts in arch/x86/kernel/kprobes.c manually. Ingo's tree did the insane "add volatile to const array", which just doesn't make sense ("volatile const"?). But we could remove the const *and* make the array volatile to make doubly sure that gcc doesn't optimize it away.. Also fix up kernel/trace/ring_buffer.c non-data-conflicts manually: the reader_lock has been turned into a raw lock by the core locking merge, and there was a new user of it introduced in this perf core merge. Make sure that new use also uses the raw accessor functions.
2011-10-14tracing: Fix returning of duplicate data after EOF in trace_pipe_rawSteven Rostedt1-2/+2
The trace_pipe_raw handler holds a cached page from the time the file is opened to the time it is closed. The cached page is used to handle the case of the user space buffer being smaller than what was read from the ring buffer. The left over buffer is held in the cache so that the next read will continue where the data left off. After EOF is returned (no more data in the buffer), the index of the cached page is set to zero. If a user app reads the page again after EOF, the check in the buffer will see that the cached page is less than page size and will return the cached page again. This will cause reading the trace_pipe_raw again after EOF to return duplicate data, making the output look like the time went backwards but instead data is just repeated. The fix is to not reset the index right after all data is read from the cache, but to reset it after all data is read and more data exists in the ring buffer. Cc: stable <stable@kernel.org> Reported-by: Jeremy Eder <jeder@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-10-14ftrace: Fix README to state tracing_on to start/stop tracingGeunsik Lim1-2/+2
tracing_enabled option is deprecated. To start/stop tracing, write to /sys/kernel/debug/tracing/tracing_on without tracing_enabled. This patch is based on Linux 3.1.0-rc1 Signed-off-by: Geunsik Lim <geunsik.lim@samsung.com> Link: http://lkml.kernel.org/r/1313127022-23830-1-git-send-email-leemgs1@gmail.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-10-11tracing: Do not allocate buffer for trace_markerSteven Rostedt1-28/+83
When doing intense tracing, the kmalloc inside trace_marker can introduce side effects to what is being traced. As trace_marker() is used by userspace to inject data into the kernel ring buffer, it needs to do so with the least amount of intrusion to the operations of the kernel or the user space application. As the ring buffer is designed to write directly into the buffer without the need to make a temporary buffer, and userspace already went through the hassle of knowing how big the write will be, we can simply pin the userspace pages and write the data directly into the buffer. This improves the impact of tracing via trace_marker tremendously! Thanks to Peter Zijlstra and Thomas Gleixner for pointing out the use of get_user_pages_fast() and kmap_atomic(). Suggested-by: Thomas Gleixner <tglx@linutronix.de> Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-10-11tracing: Warn on output if the function tracer was found corruptedSteven Rostedt1-0/+15
As the function tracer is very intrusive, lots of self checks are performed on the tracer and if something is found to be strange it will shut itself down keeping it from corrupting the rest of the kernel. This shutdown may still allow functions to be traced, as the tracing only stops new modifications from happening. Trying to stop the function tracer itself can cause more harm as it requires code modification. Although a WARN_ON() is executed, a user may not notice it. To help the user see that something isn't right with the tracing of the system a big warning is added to the output of the tracer that lets the user know that their data may be incomplete. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-09-19tracing: Add a counter clock for those that do not trust clocksSteven Rostedt1-0/+1
When debugging tight race conditions, it can be helpful to have a synchronized tracing method. Although in most cases the global clock provides this functionality, if timings is not the issue, it is more comforting to know that the order of events really happened in a precise order. Instead of using a clock, add a "counter" that is simply an incrementing atomic 64bit counter that orders the events as they are perceived to happen. The trace_clock_counter() is added from the attempt by Peter Zijlstra trying to convert the trace_clock_global() to it. I took Peter's counter code and made trace_clock_counter() instead, and added it to the choice of clocks. Just echo counter > /debug/tracing/trace_clock to activate it. Requested-by: Thomas Gleixner <tglx@linutronix.de> Requested-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-By: Valdis Kletnieks <valdis.kletnieks@vt.edu> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-09-13locking, tracing: Annotate tracing locks as rawThomas Gleixner1-5/+5
The tracing locks can be taken in atomic context and therefore cannot be preempted on -rt - annotate it. In mainline this change documents the low level nature of the lock - otherwise there's no functional difference. Lockdep and Sparse checking will work as usual. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-08-30trace: Add ring buffer stats to measure rate of eventsVaibhav Nagarnaik1-0/+13
The stats file under per_cpu folder provides the number of entries, overruns and other statistics about the CPU ring buffer. However, the numbers do not provide any indication of how full the ring buffer is in bytes compared to the overall size in bytes. Also, it is helpful to know the rate at which the cpu buffer is filling up. This patch adds an entry "bytes: " in printed stats for per_cpu ring buffer which provides the actual bytes consumed in the ring buffer. This field includes the number of bytes used by recorded events and the padding bytes added when moving the tail pointer to next page. It also adds the following time stamps: "oldest event ts:" - the oldest timestamp in the ring buffer "now ts:" - the timestamp at the time of reading The field "now ts" provides a consistent time snapshot to the userspace when being read. This is read from the same trace clock used by tracing event timestamps. Together, these values provide the rate at which the buffer is filling up, from the formula: bytes / (now_ts - oldest_event_ts) Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: Michael Rubin <mrubin@google.com> Cc: David Sharp <dhsharp@google.com> Link: http://lkml.kernel.org/r/1313531179-9323-3-git-send-email-vnagarnaik@google.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-08-30trace: Add a new readonly entry to report total buffer sizeVaibhav Nagarnaik1-0/+33
The current file "buffer_size_kb" reports the size of per-cpu buffer and not the overall memory allocated which could be misleading. A new file "buffer_total_size_kb" adds up all the enabled CPU buffer sizes and reports it. This is only a readonly entry. Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: Michael Rubin <mrubin@google.com> Cc: David Sharp <dhsharp@google.com> Link: http://lkml.kernel.org/r/1313531179-9323-2-git-send-email-vnagarnaik@google.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-07-14tracing: Have dynamic size event stack tracesSteven Rostedt1-13/+79
Currently the stack trace per event in ftace is only 8 frames. This can be quite limiting and sometimes useless. Especially when the "ignore frames" is wrong and we also use up stack frames for the event processing itself. Change this to be dynamic by adding a percpu buffer that we can write a large stack frame into and then copy into the ring buffer. For interrupts and NMIs that come in while another event is being process, will only get to use the 8 frame stack. That should be enough as the task that it interrupted will have the full stack frame anyway. Requested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-14tracing/kprobes: Fix kprobe-tracer to support stack traceMasami Hiramatsu1-5/+29
Fix to support kernel stack trace correctly on kprobe-tracer. Since the execution path of kprobe-based dynamic events is different from other tracepoint-based events, normal ftrace_trace_stack() doesn't work correctly. To fix that, this introduces ftrace_trace_stack_regs() which traces stack via pt_regs instead of current stack register. e.g. # echo p schedule+4 > /sys/kernel/debug/tracing/kprobe_events # echo 1 > /sys/kernel/debug/tracing/options/stacktrace # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable # head -n 20 /sys/kernel/debug/tracing/trace bash-2968 [000] 10297.050245: p_schedule_4: (schedule+0x4/0x4ca) bash-2968 [000] 10297.050247: <stack trace> => schedule_timeout => n_tty_read => tty_read => vfs_read => sys_read => system_call_fastpath kworker/0:1-2940 [000] 10297.050265: p_schedule_4: (schedule+0x4/0x4ca) kworker/0:1-2940 [000] 10297.050266: <stack trace> => worker_thread => kthread => kernel_thread_helper sshd-1132 [000] 10297.050365: p_schedule_4: (schedule+0x4/0x4ca) sshd-1132 [000] 10297.050365: <stack trace> => sysret_careful Note: Even with this fix, the first entry will be skipped if the probe is put on the function entry area before the frame pointer is set up (usually, that is 4 bytes (push %bp; mov %sp %bp) on x86), because stack unwinder depends on the frame pointer. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Namhyung Kim <namhyung@gmail.com> Link: http://lkml.kernel.org/r/20110608070934.17777.17116.stgit@fedora15 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-14tracing: Convert to kstrtoul_from_userPeter Huewe1-55/+10
This patch replaces the code for getting an unsigned long from a userspace buffer by a simple call to kstroul_from_user. This makes it easier to read and less error prone. Signed-off-by: Peter Huewe <peterhuewe@gmx.de> Link: http://lkml.kernel.org/r/1307476707-14762-1-git-send-email-peterhuewe@gmx.de Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-14tracing, function: Fix trace header to follow context-info optionJiri Olsa1-0/+3
The header display of function tracer does not follow the context-info option, so field names are displayed even if this option is off. Added check for TRACE_ITER_CONTEXT_INFO trace_flags. With following commands: # echo function > ./current_tracer # echo 0 > options/context-info # cat trace This is what it looked like before: # tracer: function # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | add_preempt_count <-schedule rcu_note_context_switch <-schedule ... This is what it looks like now: # tracer: function # _raw_spin_unlock_irqrestore <-hrtimer_try_to_cancel ... Signed-off-by: Jiri Olsa <jolsa@redhat.com> Link: http://lkml.kernel.org/r/1307113131-10045-4-git-send-email-jolsa@redhat.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-14tracing: Add disable_on_free optionSteven Rostedt1-2/+4
Add a trace option to disable tracing on free. When this option is set, a write into the free_buffer file will not only shrink the ring buffer down to zero, but it will also disable tracing. Cc: Vaibhav Nagarnaik <vnagarnaik@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-14tracing: Add a proc file to stop tracing and free bufferVaibhav Nagarnaik1-35/+73
The proc file entry buffer_size_kb is used to set the size of tracing buffer. The memory to expand the buffer size is kernel memory. Consider a use case where tracing is handled by a user space utility, which acts as a gate keeper for tracing requests. In an OOM condition, tracing is considered a low priority task and if the utility gets killed the ring buffer memory cannot be released back to the kernel. This patch adds a proc file called "free_buffer" whose purpose is to stop tracing and free up the ring buffer when it is closed. The user space process can then set the desired size in buffer_size_kb file and open the fd to the "free_buffer" file. Under OOM condition, if the process gets killed, the kernel closes the file descriptor. The release handler stops the tracing and releases the kernel memory automatically. Cc: Ingo Molnar <mingo@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Michael Rubin <mrubin@google.com> Cc: David Sharp <dhsharp@google.com> Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Link: http://lkml.kernel.org/r/1308012717-11148-1-git-send-email-vnagarnaik@google.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-14tracing: Use NUMA allocation for per-cpu ring buffer pagesVaibhav Nagarnaik1-4/+3
The tracing ring buffer is a group of per-cpu ring buffers where allocation and logging is done on a per-cpu basis. The events that are generated on a particular CPU are logged in the corresponding buffer. This is to provide wait-free writes between CPUs and good NUMA node locality while accessing the ring buffer. However, the allocation routines consider NUMA locality only for buffer page metadata and not for the actual buffer page. This causes the pages to be allocated on the NUMA node local to the CPU where the allocation routine is running at the time. This patch fixes the problem by using a NUMA node specific allocation routine so that the pages are allocated from a NUMA node local to the logging CPU. I tested with the getuid_microbench from autotest. It is a simple binary that calls getuid() in a loop and measures the average time for the syscall to complete. The following command was used to test: $ getuid_microbench 1000000 Compared the numbers found on kernel with and without this patch and found that logging latency decreases by 30-50 ns/call. tracing with non-NUMA allocation - 569 ns/call tracing with NUMA allocation - 512 ns/call Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Rubin <mrubin@google.com> Cc: David Sharp <dhsharp@google.com> Link: http://lkml.kernel.org/r/1304470602-20366-1-git-send-email-vnagarnaik@google.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-06-14tracing: Schedule a delayed work to call wakeup()Vaibhav Nagarnaik1-11/+12
In using syscall tracing by concurrent processes, the wakeup() that is called in the event commit function causes contention on the spin lock of the waitqueue. I enabled sys_enter_getuid and sys_exit_getuid tracepoints, and by running getuid_microbench from autotest in parallel I found that the contention causes exponential latency increase in the tracing path. The autotest binary getuid_microbench calls getuid() in a tight loop for the given number of iterations and measures the average time required to complete a single invocation of syscall. The patch schedules a delayed work after 2 ms once an event commit calls to wake up the trace wait_queue. This removes the delay caused by contention on spin lock in wakeup() and amortizes the wakeup() calls scheduled over the 2 ms period. In the following example, the script enables the sys_enter_getuid and sys_exit_getuid tracepoints and runs the getuid_microbench in parallel with the given number of processes. The output clearly shows the latency increase caused by contentions. $ ~/getuid.sh 1 1000000 calls in 0.720974253 s (720.974253 ns/call) $ ~/getuid.sh 2 1000000 calls in 1.166457554 s (1166.457554 ns/call) 1000000 calls in 1.168933765 s (1168.933765 ns/call) $ ~/getuid.sh 3 1000000 calls in 1.783827516 s (1783.827516 ns/call) 1000000 calls in 1.795553270 s (1795.553270 ns/call) 1000000 calls in 1.796493376 s (1796.493376 ns/call) $ ~/getuid.sh 4 1000000 calls in 4.483041796 s (4483.041796 ns/call) 1000000 calls in 4.484165388 s (4484.165388 ns/call) 1000000 calls in 4.484850762 s (4484.850762 ns/call) 1000000 calls in 4.485643576 s (4485.643576 ns/call) $ ~/getuid.sh 5 1000000 calls in 6.497521653 s (6497.521653 ns/call) 1000000 calls in 6.502000236 s (6502.000236 ns/call) 1000000 calls in 6.501709115 s (6501.709115 ns/call) 1000000 calls in 6.502124100 s (6502.124100 ns/call) 1000000 calls in 6.502936358 s (6502.936358 ns/call) After the patch, the latencies scale better. 1000000 calls in 0.728720455 s (728.720455 ns/call) 1000000 calls in 0.842782857 s (842.782857 ns/call) 1000000 calls in 0.883803135 s (883.803135 ns/call) 1000000 calls in 0.902077764 s (902.077764 ns/call) 1000000 calls in 0.902838202 s (902.838202 ns/call) 1000000 calls in 0.908896885 s (908.896885 ns/call) 1000000 calls in 0.932523515 s (932.523515 ns/call) 1000000 calls in 0.958009672 s (958.009672 ns/call) 1000000 calls in 0.986188020 s (986.188020 ns/call) 1000000 calls in 0.989771102 s (989.771102 ns/call) 1000000 calls in 0.933518391 s (933.518391 ns/call) 1000000 calls in 0.958897947 s (958.897947 ns/call) 1000000 calls in 1.031038897 s (1031.038897 ns/call) 1000000 calls in 1.089516025 s (1089.516025 ns/call) 1000000 calls in 1.141998347 s (1141.998347 ns/call) Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Rubin <mrubin@google.com> Cc: David Sharp <dhsharp@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1305059241-7629-1-git-send-email-vnagarnaik@google.com Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-05-10Merge commit 'v2.6.39-rc7' into perf/coreIngo Molnar1-0/+1
Merge reason: pull in the latest fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-06Regression: partial revert "tracing: Remove lock_depth from event entry"Arjan van de Ven1-0/+1
This partially reverts commit e6e1e2593592a8f6f6380496655d8c6f67431266. That commit changed the structure layout of the trace structure, which in turn broke PowerTOP (1.9x generation) quite badly. I appreciate not wanting to expose the variable in question, and PowerTOP was not using it, so I've replaced the variable with just a padding field - that way if in the future a new field is needed it can just use this padding field. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-27Merge branch 'tip/perf/core' of ↵Ingo Molnar1-3/+12
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core Conflicts: include/linux/perf_event.h Merge reason: pick up the latest jump-label enhancements, they are cooked ready. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-04tracing: Avoid soft lockup in trace_pipeJiri Olsa1-3/+12
running following commands: # enable the binary option echo 1 > ./options/bin # disable context info option echo 0 > ./options/context-info # tracing only events echo 1 > ./events/enable cat trace_pipe plus forcing system to generate many tracing events, is causing lockup (in NON preemptive kernels) inside tracing_read_pipe function. The issue is also easily reproduced by running ltp stress test. (ftrace_stress_test.sh) The reasons are: - bin/hex/raw output functions for events are set to trace_nop_print function, which prints nothing and returns TRACE_TYPE_HANDLED value - LOST EVENT trace do not handle trace_seq overflow These reasons force the while loop in tracing_read_pipe function never to break. The attached patch fixies handling of lost event trace, and changes trace_nop_print to print minimal info, which is needed for the correct tracing_read_pipe processing. v2 changes: - omit the cond_resched changes by trace_nop_print changes - WARN changed to WARN_ONCE and added info to be able to find out the culprit v3 changes: - make more accurate patch comment Signed-off-by: Jiri Olsa <jolsa@redhat.com> LKML-Reference: <20110325110518.GC1922@jolsa.brq.redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-03-31Fix common misspellingsLucas De Marchi1-1/+1
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-10tracing: Fix irqoff selftest expanding max bufferSteven Rostedt1-0/+9
If the kernel command line declares a tracer "ftrace=sometracer" and that tracer is either not defined or is enabled after irqsoff, then the irqs off selftest will fail with the following error: Testing tracer irqsoff: ------------[ cut here ]------------ WARNING: at /home/rostedt/work/autotest/nobackup/linux-test.git/kernel/trace/tra ce.c:713 update_max_tr_single+0xfa/0x11b() Hardware name: Modules linked in: Pid: 1, comm: swapper Not tainted 2.6.38-rc8-test #1 Call Trace: [<c0441d9d>] ? warn_slowpath_common+0x65/0x7a [<c049adb2>] ? update_max_tr_single+0xfa/0x11b [<c0441dc1>] ? warn_slowpath_null+0xf/0x13 [<c049adb2>] ? update_max_tr_single+0xfa/0x11b [<c049e454>] ? stop_critical_timing+0x154/0x204 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1 [<c049e529>] ? time_hardirqs_on+0x25/0x28 [<c0468bca>] ? trace_hardirqs_on_caller+0x18/0x12f [<c0468cec>] ? trace_hardirqs_on+0xb/0xd [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1 [<c049b6b8>] ? register_tracer+0xf8/0x1a3 [<c14e93fe>] ? init_irqsoff_tracer+0xd/0x11 [<c040115e>] ? do_one_initcall+0x71/0x121 [<c14e93f1>] ? init_irqsoff_tracer+0x0/0x11 [<c14ce3a9>] ? kernel_init+0x13a/0x1b6 [<c14ce26f>] ? kernel_init+0x0/0x1b6 [<c0403842>] ? kernel_thread_helper+0x6/0x10 ---[ end trace e93713a9d40cd06c ]--- .. no entries found ..FAILED! What happens is the "ftrace=..." will expand the ring buffer to its default size (from its minimum size) but it will not expand the max ring buffer (the ring buffer to store maximum latencies). When the irqsoff test runs, it will call the ring buffer swap routine that checks if the max ring buffer is the same size as the normal ring buffer, and will fail if it is not. This causes the test to fail. The solution is to expand the max ring buffer before running the self test if the max ring buffer is used by that tracer and the normal ring buffer is expanded. The max ring buffer should be shrunk again after the test is done to save space. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-03-10tracing: Remove lock_depth from event entrySteven Rostedt1-5/+3
The lock_depth field in the event headers was added as a temporary data point for help in removing the BKL. Now that the BKL is pretty much been removed, we can remove this field. This in turn changes the header from 12 bytes to 8 bytes, removing the 4 byte buffer that gcc would insert if the first field in the data load was 8 bytes in size. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-03-09tracing: Add an 'overwrite' trace_option.David Sharp1-6/+11
Add an "overwrite" trace_option for ftrace to control whether the buffer should be overwritten on overflow or not. The default remains to overwrite old events when the buffer is full. This patch adds the option to instead discard newest events when the buffer is full. This is useful to get a snapshot of traces just after enabling traces. Dropping the current event is also a simpler code path. Signed-off-by: David Sharp <dhsharp@google.com> LKML-Reference: <1291844807-15481-1-git-send-email-dhsharp@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-02-08tracing: Deprecate tracing_enabled for tracing_onSteven Rostedt1-0/+4
tracing_enabled should not be used, it is heavy weight and does not do much in helping lower the overhead. tracing_on should be used instead. Warn users to use tracing_on when tracing_enabled is used as it will soon be removed from the tracing directory. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-01-07tracing: Fix preempt count leakLi Zefan1-4/+2
While running my ftrace stress test, this showed up: BUG: sleeping function called from invalid context at mm/mmap.c:233 ... note: cat[3293] exited with preempt_count 1 The bug was introduced by commit 91e86e560d0b3ce4c5fc64fd2bbb99f856a30a4e ("tracing: Fix recursive user stack trace") Cc: <stable@kernel.org> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4D0089AC.1020802@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-12-16Merge branch 'tip/perf/urgent' of ↵Ingo Molnar1-1/+9
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/urgent
2010-11-30tracing: Fix panic when lseek() called on "trace" opened for writingSlava Pestov1-1/+9
The file_ops struct for the "trace" special file defined llseek as seq_lseek(). However, if the file was opened for writing only, seq_open() was not called, and the seek would dereference a null pointer, file->private_data. This patch introduces a new wrapper for seq_lseek() which checks if the file descriptor is opened for reading first. If not, it does nothing. Cc: <stable@kernel.org> Signed-off-by: Slava Pestov <slavapestov@google.com> LKML-Reference: <1290640396-24179-1-git-send-email-slavapestov@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-11-27Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds1-0/+19
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf symbols: Remove incorrect open-coded container_of() perf record: Handle restrictive permissions in /proc/{kallsyms,modules} x86/kprobes: Prevent kprobes to probe on save_args() irq_work: Drop cmpxchg() result perf: Fix owner-list vs exit x86, hw_nmi: Move backtrace_mask declaration under ARCH_HAS_NMI_WATCHDOG tracing: Fix recursive user stack trace perf,hw_breakpoint: Initialize hardware api earlier x86: Ignore trap bits on single step exceptions tracing: Force arch_local_irq_* notrace for paravirt tracing: Fix module use of trace_bprintk()
2010-11-17BKL: remove extraneous #include <smp_lock.h>Arnd Bergmann1-1/+0
The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-12tracing: Fix recursive user stack traceSteven Rostedt1-0/+19
The user stack trace can fault when examining the trace. Which would call the do_page_fault handler, which would trace again, which would do the user stack trace, which would fault and call do_page_fault again ... Thus this is causing a recursive bug. We need to have a recursion detector here. [ Resubmitted by Jiri Olsa ] [ Eric Dumazet recommended using __this_cpu_* instead of __get_cpu_* ] Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> LKML-Reference: <1289390172-9730-3-git-send-email-jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-21tracing: Do not limit the size of the number of CPU buffersSteven Rostedt1-6/+2
The tracing per_cpu buffers were limited to 999 CPUs for a mear savings in stack space of a char array. Up the array to 30 characters which is more than enough to hold a 64 bit number. Reported-by: Robin Holt <holt@sgi.com> Suggested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-18tracing/trivial: Remove cast from void*matt mooney1-1/+1
Unnecessary cast from void* in assignment. Signed-off-by: matt mooney <mfm@muteddisk.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-16Merge branch 'tip/perf/urgent-3' of ↵Steven Rostedt1-3/+8
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into trace/tip/perf/urgent-4 Conflicts: kernel/trace/trace_events.c Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-13tracing: Sanitize value returned from write(trace_marker, "...", len)Marcin Slusarz1-3/+8
When userspace code writes non-new-line-terminated string to trace_marker file, write handler appends new-line and returns number of bytes written to trace buffer, so write(fd, "abc", 3) will return 4 That's unexpected and unfortunately it confuses glibc's fprintf function. Example: int main() { fprintf(stderr, "abc"); return 0; } $ gcc test.c -o test $ echo mmiotrace > /sys/kernel/debug/tracing/current_tracer $ ./test 2>/sys/kernel/debug/tracing/trace_marker results in infinite loop: write(fd, "abc", 3) = 4 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 (...) ...and kernel trace buffer full of empty markers. Fix it by sanitizing write return value. Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com> LKML-Reference: <20100727231801.GB2826@joi.lan> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-07Merge branch 'bkl/core' of ↵Linus Torvalds1-8/+0
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing * 'bkl/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing: do_coredump: Do not take BKL init: Remove the BKL from startup code
2010-08-06Merge branch 'perf-core-for-linus' of ↵Linus Torvalds1-72/+55
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (162 commits) tracing/kprobes: unregister_trace_probe needs to be called under mutex perf: expose event__process function perf events: Fix mmap offset determination perf, powerpc: fsl_emb: Restore setting perf_sample_data.period perf, powerpc: Convert the FSL driver to use local64_t perf tools: Don't keep unreferenced maps when unmaps are detected perf session: Invalidate last_match when removing threads from rb_tree perf session: Free the ref_reloc_sym memory at the right place x86,mmiotrace: Add support for tracing STOS instruction perf, sched migration: Librarize task states and event headers helpers perf, sched migration: Librarize the GUI class perf, sched migration: Make the GUI class client agnostic perf, sched migration: Make it vertically scrollable perf, sched migration: Parameterize cpu height and spacing perf, sched migration: Fix key bindings perf, sched migration: Ignore unhandled task states perf, sched migration: Handle ignored migrate out events perf: New migration tool overview tracing: Drop cpparg() macro perf: Use tracepoint_synchronize_unregister() to flush any pending tracepoint call ... Fix up trivial conflicts in Makefile and drivers/cpufreq/cpufreq.c
2010-08-05ftrace,kdb: Extend kdb to be able to dump the ftrace bufferJason Wessel1-21/+22
Add in a helper function to allow the kdb shell to dump the ftrace buffer. Modify trace.c to expose the capability to iterate over the ftrace buffer in a read only capacity. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> CC: Frederic Weisbecker <fweisbec@gmail.com>
2010-07-23Merge branch 'tip/perf/core' of ↵Ingo Molnar1-8/+38
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
2010-07-22trace: strlen() return doesn't account for the NULLDan Carpenter1-1/+1
We need to add one to the strlen() return because of the NULL character. The type->name here generally comes from the kernel and I don't think any of them come close to being MAX_TRACER_SIZE (100) characters long so this is basically a cleanup. Signed-off-by: Dan Carpenter <error27@gmail.com> LKML-Reference: <20100710100644.GV19184@bicker> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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