Commit Graph

16 Commits

Author SHA1 Message Date
Frederic Weisbecker
61c1917f47 perf events, x86/stacktrace: Make stack walking optional
The current print_context_stack helper that does the stack
walking job is good for usual stacktraces as it walks through
all the stack and reports even addresses that look unreliable,
which is nice when we don't have frame pointers for example.

But we have users like perf that only require reliable
stacktraces, and those may want a more adapted stack walker, so
lets make this function a callback in stacktrace_ops that users
can tune for their needs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1261024834-5336-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-17 09:56:19 +01:00
Vegard Nossum
acc6be5405 x86: add save_stack_trace_bp() for tracing from a specific stack frame
This will help kmemcheck (and possibly other debugging tools) since we
can now simply pass regs->bp to the stack tracer instead of specifying
the number of stack frames to skip, which is unreliable if gcc decides
to inline functions, etc.

Note that this makes the API incomplete for other architectures, but I
expect that those can be updated lazily, e.g. when they need it.

Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
2009-06-12 23:01:05 +02:00
Steven Rostedt
29a679754b x86/stacktrace: return 0 instead of -1 for stack ops
If we return -1 in the ops->stack for the stacktrace saving, we end up
breaking out of the loop if the stack we are tracing is in the exception
stack. This causes traces like:

          <idle>-0     [002] 34263.745825: raise_softirq_irqoff <-__blk_complete_request
          <idle>-0     [002] 34263.745826:
 <= 0
 <= 0
 <= 0
 <= 0
 <= 0
 <= 0
 <= 0

By returning "0" instead, the irq stack is saved as well, and we see:

          <idle>-0     [003]   883.280992: raise_softirq_irqoff <-__hrtimer_star
t_range_ns
          <idle>-0     [003]   883.280992:
 <= hrtimer_start_range_ns
 <= tick_nohz_restart_sched_tick
 <= cpu_idle
 <= start_secondary
 <=
 <= 0
 <= 0

[ Impact: record stacks from interrupts ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-05-14 23:19:09 -04:00
Ingo Molnar
8f47e16348 x86: update copyrights
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-31 04:21:18 +01:00
Török Edwin
8d7c6a9616 tracing/stack-tracer: fix style issues
Impact: cleanup

Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23 11:53:48 +01:00
Török Edwin
02b67518e2 tracing: add support for userspace stacktraces in tracing/iter_ctrl
Impact: add new (default-off) tracing visualization feature

Usage example:

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

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

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

Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23 09:25:15 +01:00
Ingo Molnar
8594698ebd stacktrace: fix modular build, export print_stack_trace and save_stack_trace
fix:

ERROR: "print_stack_trace" [kernel/backtracetest.ko] undefined!
ERROR: "save_stack_trace" [kernel/backtracetest.ko] undefined!

Signed-off-by: Ingo Molnar <mingo@elte.hu>

and fix:

  Building modules, stage 2.
  MODPOST 376 modules
ERROR: "print_stack_trace" [kernel/backtracetest.ko] undefined!
make[1]: *** [__modpost] Error 1

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-30 09:20:55 +02:00
Vegard Nossum
1650743cdc x86: don't save unreliable stack trace entries
Currently, there is no way for print_stack_trace() to determine whether
a given stack trace entry was deemed reliable or not, simply because
save_stack_trace() does not record this information. (Perhaps needless
to say, this makes the saved stack traces A LOT harder to read, and
probably with no other benefits, since debugging features that use
save_stack_trace() most likely also require frame pointers, etc.)

This patch reverts to the old behaviour of only recording the reliable trace
entries for saved stack traces.

Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-02-26 12:55:58 +01:00
Jan Engelhardt
ade1af7712 x86: remove unneded casts
x86: remove unneeded casts

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:23 +01:00
Arjan van de Ven
5bc27dc2f5 x86: pull bp calculation earlier into the backtrace path
Right now, we take the stack pointer early during the backtrace path, but
only calculate bp several functions deep later, making it hard to reconcile
the stack and bp backtraces (as well as showing several internal backtrace
functions on the stack with bp based backtracing).

This patch moves the bp taking to the same place we take the stack pointer;
sadly this ripples through several layers of the back tracing stack,
but it's not all that bad in the end I hope.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:07 +01:00
Arjan van de Ven
bc850d6b37 x86: add the capability to print fuzzy backtraces
For enhancing the 32 bit EBP based backtracer, I need the capability
for the backtracer to tell it's customer that an entry is either
reliable or unreliable, and the backtrace printing code then needs to
print the unreliable ones slightly different.

This patch adds the basic capability, the next patch will add a user
of this capability.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:07 +01:00
Thomas Gleixner
3abf024d2a x86: nuke a ton of unused exports
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-30 13:30:28 +01:00
Arjan van de Ven
9745512ce7 sched: latencytop support
LatencyTOP kernel infrastructure; it measures latencies in the
scheduler and tracks it system wide and per process.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-25 21:08:34 +01:00
Jan Beulich
9689ba8ad0 x86: constify stacktrace_ops
.. as they're never written to.

[ tglx: arch/x86 adaptation ]

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-17 20:16:11 +02:00
Dave Jones
835c34a168 Delete filenames in comments.
Since the x86 merge, lots of files that referenced their own filenames
are no longer correct.  Rather than keep them up to date, just delete
them, as they add no real value.

Additionally:
- fix up comment formatting in scx200_32.c
- Remove a credit from myself in setup_64.c from a time when we had no SCM
- remove longwinded history from tsc_32.c which can be figured out from
  git.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-13 10:01:23 -07:00
Thomas Gleixner
250c22777f x86_64: move kernel
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-11 11:17:24 +02:00