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* tracing: Fix ftrace_dump()Steven Rostedt (Red Hat)2013-05-111-30/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 7fe70b579c9e3daba71635e31b6189394e7b79d3 upstream. ftrace_dump() had a lot of issues. What ftrace_dump() does, is when ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it will dump out the ftrace buffers to the console when either a oops, panic, or a sysrq-z occurs. This was written a long time ago when ftrace was fragile to recursion. But it wasn't written well even for that. There's a possible deadlock that can occur if a ftrace_dump() is happening and an NMI triggers another dump. This is because it grabs a lock before checking if the dump ran. It also totally disables ftrace, and tracing for no good reasons. As the ring_buffer now checks if it is read via a oops or NMI, where there's a chance that the buffer gets corrupted, it will disable itself. No need to have ftrace_dump() do the same. ftrace_dump() is now cleaned up where it uses an atomic counter to make sure only one dump happens at a time. A simple atomic_inc_return() is enough that is needed for both other CPUs and NMIs. No need for a spinlock, as if one CPU is running the dump, no other CPU needs to do it too. The tracing_on variable is turned off and not turned on. The original code did this, but it wasn't pretty. By just disabling this variable we get the result of not seeing traces that happen between crashes. For sysrq-z, it doesn't get turned on, but the user can always write a '1' to the tracing_on file. If they are using sysrq-z, then they should know about tracing_on. The new code is much easier to read and less error prone. No more deadlock possibility when an NMI triggers here. Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Check return value of tracing_init_dentry()Namhyung Kim2013-05-071-0/+2
| | | | | | | | | | | | | | | commit ed6f1c996bfe4b6e520cf7a74b51cd6988d84420 upstream. Check return value and bail out if it's NULL. Link: http://lkml.kernel.org/r/1365553093-10180-2-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Prevent buffer overwrite disabled for latency tracersSteven Rostedt (Red Hat)2013-04-051-6/+29
| | | | | | | | | | | | | | | | | | | | | | commit 613f04a0f51e6e68ac6fe571ab79da3c0a5eb4da upstream. The latency tracers require the buffers to be in overwrite mode, otherwise they get screwed up. Force the buffers to stay in overwrite mode when latency tracers are enabled. Added a flag_changed() method to the tracer structure to allow the tracers to see what flags are being changed, and also be able to prevent the change from happing. [Backported for 3.4-stable. Re-added current_trace NULL checks; removed allocated_snapshot field; adapted to tracing_trace_options_write without trace_set_options.] Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Lingzhu Xiang <lxiang@redhat.com> Reviewed-by: CAI Qian <caiqian@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Protect tracer flags with trace_types_lockSteven Rostedt (Red Hat)2013-04-051-7/+12
| | | | | | | | | | | | | | | | | | | | commit 69d34da2984c95b33ea21518227e1f9470f11d95 upstream. Seems that the tracer flags have never been protected from synchronous writes. Luckily, admins don't usually modify the tracing flags via two different tasks. But if scripts were to be used to modify them, then they could get corrupted. Move the trace_types_lock that protects against tracers changing to also protect the flags being set. [Backported for 3.4, 3.0-stable. Moved return to after unlock.] Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Lingzhu Xiang <lxiang@redhat.com> Reviewed-by: CAI Qian <caiqian@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Fix race in snapshot swappingSteven Rostedt (Red Hat)2013-03-281-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | commit 2721e72dd10f71a3ba90f59781becf02638aa0d9 upstream. Although the swap is wrapped with a spin_lock, the assignment of the temp buffer used to swap is not within that lock. It needs to be moved into that lock, otherwise two swaps happening on two different CPUs, can end up using the wrong temp buffer to assign in the swap. Luckily, all current callers of the swap function appear to have their own locks. But in case something is added that allows two different callers to call the swap, then there's a chance that this race can trigger and corrupt the buffers. New code is coming soon that will allow for this race to trigger. I've Cc'd stable, so this bug will not show up if someone backports one of the changes that can trigger this bug. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: change CPU ring buffer state from tracing_cpumaskVaibhav Nagarnaik2012-07-161-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 71babb2705e2203a64c27ede13ae3508a0d2c16c upstream. According to Documentation/trace/ftrace.txt: tracing_cpumask: This is a mask that lets the user only trace on specified CPUS. The format is a hex string representing the CPUS. The tracing_cpumask currently doesn't affect the tracing state of per-CPU ring buffers. This patch enables/disables CPU recording as its corresponding bit in tracing_cpumask is set/unset. Link: http://lkml.kernel.org/r/1336096792-25373-3-git-send-email-vnagarnaik@google.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Laurent Chavey <chavey@google.com> Cc: Justin Teravest <teravest@google.com> Cc: David Sharp <dhsharp@google.com> Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tracing: Fix returning of duplicate data after EOF in trace_pipe_rawSteven Rostedt2011-11-111-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | commit 436fc280261dcfce5af38f08b89287750dc91cd2 upstream. 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. Reported-by: Jeremy Eder <jeder@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Merge commit 'v2.6.39-rc7' into perf/coreIngo Molnar2011-05-101-0/+1
|\ | | | | | | | | | | Merge reason: pull in the latest fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Regression: partial revert "tracing: Remove lock_depth from event entry"Arjan van de Ven2011-05-061-0/+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>
* | Merge branch 'tip/perf/core' of ↵Ingo Molnar2011-04-271-3/+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>
| * tracing: Avoid soft lockup in trace_pipeJiri Olsa2011-04-041-3/+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>
* | Fix common misspellingsLucas De Marchi2011-03-311-1/+1
|/ | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* tracing: Fix irqoff selftest expanding max bufferSteven Rostedt2011-03-101-0/+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>
* tracing: Remove lock_depth from event entrySteven Rostedt2011-03-101-5/+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>
* tracing: Add an 'overwrite' trace_option.David Sharp2011-03-091-6/+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>
* tracing: Deprecate tracing_enabled for tracing_onSteven Rostedt2011-02-081-0/+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>
* tracing: Fix preempt count leakLi Zefan2011-01-071-4/+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>
* Merge branch 'tip/perf/urgent' of ↵Ingo Molnar2010-12-161-1/+9
|\ | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/urgent
| * tracing: Fix panic when lseek() called on "trace" opened for writingSlava Pestov2010-11-301-1/+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>
* | Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds2010-11-271-0/+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()
| * tracing: Fix recursive user stack traceSteven Rostedt2010-11-121-0/+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>
* | BKL: remove extraneous #include <smp_lock.h>Arnd Bergmann2010-11-171-1/+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>
* tracing: Do not limit the size of the number of CPU buffersSteven Rostedt2010-10-211-6/+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>
* tracing/trivial: Remove cast from void*matt mooney2010-10-181-1/+1
| | | | | | | Unnecessary cast from void* in assignment. Signed-off-by: matt mooney <mfm@muteddisk.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* Merge branch 'tip/perf/urgent-3' of ↵Steven Rostedt2010-08-161-3/+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>
| * tracing: Sanitize value returned from write(trace_marker, "...", len)Marcin Slusarz2010-08-131-3/+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>
* | Merge branch 'bkl/core' of ↵Linus Torvalds2010-08-071-8/+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
| * | init: Remove the BKL from startup codeArnd Bergmann2010-07-091-8/+0
| |/ | | | | | | | | | | | | | | | | | | | | I have shown by code review that no driver takes the BKL at init time any more, so whatever the init code was locking against is no longer there and it is now safe to remove the BKL there. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Steven Rostedt <rostedt@goodmis> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | Merge branch 'perf-core-for-linus' of ↵Linus Torvalds2010-08-061-72/+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
| * \ Merge branch 'tip/perf/core' of ↵Ingo Molnar2010-07-231-8/+38
| |\ \ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
| | * | trace: strlen() return doesn't account for the NULLDan Carpenter2010-07-221-1/+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>
| | * | tracing: Shrink max latency ringbuffer if unnecessaryKOSAKI Motohiro2010-07-211-6/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Documentation/trace/ftrace.txt says buffer_size_kb: This sets or displays the number of kilobytes each CPU buffer can hold. The tracer buffers are the same size for each CPU. The displayed number is the size of the CPU buffer and not total size of all buffers. The trace buffers are allocated in pages (blocks of memory that the kernel uses for allocation, usually 4 KB in size). If the last page allocated has room for more bytes than requested, the rest of the page will be used, making the actual allocation bigger than requested. ( Note, the size may not be a multiple of the page size due to buffer management overhead. ) This can only be updated when the current_tracer is set to "nop". But it's incorrect. currently total memory consumption is 'buffer_size_kb x CPUs x 2'. Why two times difference is there? because ftrace implicitly allocate the buffer for max latency too. That makes sad result when admin want to use large buffer. (If admin want full logging and makes detail analysis). example, If admin have 24 CPUs machine and write 200MB to buffer_size_kb, the system consume ~10GB memory (200MB x 24 x 2). umm.. 5GB memory waste is usually unacceptable. Fortunatelly, almost all users don't use max latency feature. The max latency buffer can be disabled easily. This patch shrink buffer size of the max latency buffer if unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> LKML-Reference: <20100701104554.DA2D.A69D9226@jp.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| | * | tracing: Allow to disable cmdline recordingLi Zefan2010-07-201-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We found that even enabling a single trace event that will rarely be triggered can add big overhead to context switch. (lmbench context switch test) ------------------------------------------------- 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/64K ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw ------ ------ ------ ------ ------ ------- ------- 2.19 2.3 2.21 2.56 2.13 2.54 2.07 2.39 2.51 2.35 2.75 2.27 2.81 2.24 The overhead is 6% ~ 11%. It's because when a trace event is enabled 3 tracepoints (sched_switch, sched_wakeup, sched_wakeup_new) will be activated to map pid to cmdname. We'd like to avoid this overhead, so add a trace option '(no)record-cmd' to allow to disable cmdline recording. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4C2D57F4.2050204@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | tracing: Use generic_file_llseek for debugfsArnd Bergmann2010-07-201-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The default for llseek will change to no_llseek, so the tracing debugfs files need to add explicit .llseek assignments. Since we're dealing with regular files from a VFS perspective, use generic_file_llseek. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: John Kacur <jkacur@redhat.com> Cc: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <1278538820-1392-10-git-send-email-arnd@arndb.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| * | | tracing: Remove special tracesFrederic Weisbecker2010-07-201-55/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Special traces type was only used by sysprof. Lets remove it now that sysprof ftrace plugin has been dropped. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Soeren Sandmann <sandmann@daimi.au.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Li Zefan <lizf@cn.fujitsu.com>
| * | | tracing: Remove sysprof ftrace pluginFrederic Weisbecker2010-07-201-3/+0
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sysprof ftrace plugin doesn't seem to be seriously used somewhere. There is a branch in the sysprof tree that makes an interface to it, but the real sysprof tool uses either its own module or perf events. Drop the sysprof ftrace plugin then, as it's mostly useless. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Soeren Sandmann <sandmann@daimi.au.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Li Zefan <lizf@cn.fujitsu.com>
| * | Merge branch 'perf/core' of ↵Ingo Molnar2010-06-091-3/+0
| |\ \ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core
| | * | tracing: Remove boot tracerAmérico Wang2010-06-081-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The boot tracer is useless. It simply logs the initcalls but in fact these initcalls are also logged through printk while using the initcall_debug kernel parameter. Nobody seem to be using it so far. Then just remove it. Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Chase Douglas <chase.douglas@canonical.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <20100526105753.GA5677@cr0.nay.redhat.com> [ remove the hooks in main.c, and the headers ] Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| * | | Merge branch 'tip/perf/core-3' of ↵Ingo Molnar2010-06-081-3/+2
| |\ \ \ | | |_|/ | |/| | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
| | * | tracing: Remove ftrace_preempt_disable/enableSteven Rostedt2010-06-031-3/+2
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ftrace_preempt_disable/enable functions were to address a recursive race caused by the function tracer. The function tracer traces all functions which makes it easily susceptible to recursion. One area was preempt_enable(). This would call the scheduler and the schedulre would call the function tracer and loop. (So was it thought). The ftrace_preempt_disable/enable was made to protect against recursion inside the scheduler by storing the NEED_RESCHED flag. If it was set before the ftrace_preempt_disable() it would not call schedule on ftrace_preempt_enable(), thinking that if it was set before then it would have already scheduled unless it was already in the scheduler. This worked fine except in the case of SMP, where another task would set the NEED_RESCHED flag for a task on another CPU, and then kick off an IPI to trigger it. This could cause the NEED_RESCHED to be saved at ftrace_preempt_disable() but the IPI to arrive in the the preempt disabled section. The ftrace_preempt_enable() would not call the scheduler because the flag was already set before entring the section. This bug would cause a missed preemption check and cause lower latencies. Investigating further, I found that the recusion caused by the function tracer was not due to schedule(), but due to preempt_schedule(). Now that preempt_schedule is completely annotated with notrace, the recusion no longer is an issue. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | ftrace,kdb: Extend kdb to be able to dump the ftrace bufferJason Wessel2010-08-051-21/+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>
* | Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds2010-05-301-6/+0
|\ \ | |/ |/| | | | | | | | | | | | | | | | | 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 tui: Fix last use_browser problem related to .perfconfig perf symbols: Add the build id cache to the vmlinux path perf tui: Reset use_browser if stdout is not a tty ring-buffer: Move zeroing out excess in page to ring buffer code ring-buffer: Reset "real_end" when page is filled
| * ring-buffer: Move zeroing out excess in page to ring buffer codeSteven Rostedt2010-05-251-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the trace splice code zeros out the excess bytes in the page before sending it off to userspace. This is to make sure userspace is not getting anything it should not be when reading the pages, because the excess data was never initialized to zero before writing (for perfomance reasons). But the splice code has no business in doing this work, it should be done by the ring buffer. With the latest changes for recording lost events, the splice code gets it wrong anyway. Move the zeroing out of excess bytes into the ring buffer code. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | Merge branch 'perf-core-for-linus' of ↵Linus Torvalds2010-05-271-4/+5
|\ \ | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: (61 commits) tracing: Add __used annotation to event variable perf, trace: Fix !x86 build bug perf report: Support multiple events on the TUI perf annotate: Fix up usage of the build id cache x86/mmiotrace: Remove redundant instruction prefix checks perf annotate: Add TUI interface perf tui: Remove annotate from popup menu after failure perf report: Don't start the TUI if -D is used perf: Fix getline undeclared perf: Optimize perf_tp_event_match() perf: Remove more code from the fastpath perf: Optimize the !vmalloc backed buffer perf: Optimize perf_output_copy() perf: Fix wakeup storm for RO mmap()s perf-record: Share per-cpu buffers perf-record: Remove -M perf: Ensure that IOC_OUTPUT isn't used to create multi-writer buffers perf, trace: Optimize tracepoints by using per-tracepoint-per-cpu hlist to track events perf, trace: Optimize tracepoints by removing IRQ-disable from perf/tracepoint interaction perf tui: Allow disabling the TUI on a per command basis in ~/.perfconfig ...
| * tracing: Allow events to share their print functionsSteven Rostedt2010-05-141-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Multiple events may use the same method to print their data. Instead of having all events have a pointer to their print funtions, the trace_event structure now points to a trace_event_functions structure that will hold the way to print ouf the event. The event itself is now passed to the print function to let the print function know what kind of event it should print. This opens the door to consolidating the way several events print their output. text data bss dec hex filename 4913961 1088356 861512 6863829 68bbd5 vmlinux.orig 4900382 1048964 861512 6810858 67ecea vmlinux.init 4900446 1049028 861512 6810986 67ed6a vmlinux.preprint This change slightly increases the size but is needed for the next change. v3: Fix the branch tracer events to handle this change. v2: Fix the new function graph tracer event calls to handle this change. Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | Merge branch 'master' into for-2.6.35Jens Axboe2010-05-211-36/+91
|\ \ | |/ | | | | | | | | | | Conflicts: fs/ext3/fsync.c Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * ring-buffer: Make non-consuming read less expensive with lots of cpus.David Miller2010-04-271-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When performing a non-consuming read, a synchronize_sched() is performed once for every cpu which is actively tracing. This is very expensive, and can make it take several seconds to open up the 'trace' file with lots of cpus. Only one synchronize_sched() call is actually necessary. What is desired is for all cpus to see the disabling state change. So we transform the existing sequence: for_each_cpu() { ring_buffer_read_start(); } where each ring_buffer_start() call performs a synchronize_sched(), into the following: for_each_cpu() { ring_buffer_read_prepare(); } ring_buffer_read_prepare_sync(); for_each_cpu() { ring_buffer_read_start(); } wherein only the single ring_buffer_read_prepare_sync() call needs to do the synchronize_sched(). The first phase, via ring_buffer_read_prepare(), allocates the 'iter' memory and increments ->record_disabled. In the second phase, ring_buffer_read_prepare_sync() makes sure this ->record_disabled state is visible fully to all cpus. And in the final third phase, the ring_buffer_read_start() calls reset the 'iter' objects allocated in the first phase since we now know that none of the cpus are adding trace entries any more. This makes openning the 'trace' file nearly instantaneous on a sparc64 Niagara2 box with 128 cpus tracing. Signed-off-by: David S. Miller <davem@davemloft.net> LKML-Reference: <20100420.154711.11246950.davem@davemloft.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Add graph output support for irqsoff tracerJiri Olsa2010-04-271-13/+22
| | | | | | | | | | | | | | | | | | | | Add function graph output to irqsoff tracer. The graph output is enabled by setting new 'display-graph' trace option. Signed-off-by: Jiri Olsa <jolsa@redhat.com> LKML-Reference: <1270227683-14631-4-git-send-email-jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Dump either the oops's cpu source or all cpus buffersFrederic Weisbecker2010-04-211-12/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ftrace_dump_on_oops kernel parameter, sysctl and sysrq let one dump every cpu buffers when an oops or panic happens. It's nice when you have few cpus but it may take ages if have many, plus you miss the real origin of the problem in all the cpu traces. Sometimes, all you need is to dump the cpu buffer that triggered the opps, most of the time it is our main interest. This patch modifies ftrace_dump_on_oops to handle this choice. The ftrace_dump_on_oops kernel parameter, when it comes alone, has the same behaviour than before. But ftrace_dump_on_oops=orig_cpu will only dump the buffer of the cpu that oops'ed. Similarly, sysctl kernel.ftrace_dump_on_oops=1 and echo 1 > /proc/sys/kernel/ftrace_dump_on_oops keep their previous behaviour. But setting 2 jumps into cpu origin dump mode. v2: Fix double setup v3: Fix spelling issues reported by Randy Dunlap v4: Also update __ftrace_dump in the selftests Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
| * Merge branch 'tip/tracing/core' of ↵Ingo Molnar2010-04-141-1/+1
| |\ | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/core
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