aha/kernel/trace
Jiri Olsa be1eca3931 tracing: Fix function graph trace_pipe to properly display failed entries
There is a case where the graph tracer might get confused and omits
displaying of a single record.  This applies mostly with the trace_pipe
since it is unlikely that the trace_seq buffer will overflow with the
trace file.

As the function_graph tracer goes through the trace entries keeping a
pointer to the current record:

current ->  func1 ENTRY
            func2 ENTRY
            func2 RETURN
            func1 RETURN

When an function ENTRY is encountered, it moves the pointer to the
next entry to check if the function is a nested or leaf function.

            func1 ENTRY
current ->  func2 ENTRY
            func2 RETURN
            func1 RETURN

If the rest of the writing of the function fills the trace_seq buffer,
then the trace_pipe read will ignore this entry. The next read will
Now start at the current location, but the first entry (func1) will
be discarded.

This patch keeps a copy of the current entry in the iterator private
storage and will keep track of when the trace_seq buffer fills. When
the trace_seq buffer fills, it will reuse the copy of the entry in the
next iteration.

[
  This patch has been largely modified by Steven Rostedt in order to
  clean it up and simplify it. The original idea and concept was from
  Jirka and for that, this patch will go under his name to give him
  the credit he deserves. But because this was modify by Steven Rostedt
  anything wrong with the patch should be blamed on Steven.
]

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1259067458-27143-1-git-send-email-jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-12-09 14:09:06 -05:00
..
blktrace.c Add a tracepoint for block request remapping 2009-10-01 21:19:34 +02:00
ftrace.c Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-05 09:53:36 -08:00
Kconfig Merge branch 'tracing/hw-breakpoints' into perf/core 2009-11-21 14:07:23 +01:00
kmemtrace.c kmemtrace: Fix up tracer registration 2009-10-01 11:53:44 +02:00
Makefile Merge branch 'tracing/hw-breakpoints' into perf/core 2009-11-21 14:07:23 +01:00
power-traces.c tracing, perf: Convert the power tracer into an event tracer 2009-09-19 11:42:12 +02:00
ring_buffer.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-05 15:30:21 -08:00
ring_buffer_benchmark.c ring-buffer-benchmark: Add parameters to set produce/consumer priorities 2009-11-25 14:14:15 -05:00
trace.c tracing: Buffer the output of seq_file in case of filled buffer 2009-12-09 13:55:26 -05:00
trace.h tracing: Add pipe_close interface 2009-12-07 12:01:35 -05:00
trace_boot.c tracing: add filter event logic to special, mmiotrace and boot tracers 2009-09-12 23:34:04 -04:00
trace_branch.c tracing: user local buffer variable for trace branch tracer 2009-10-07 21:53:41 -04:00
trace_clock.c tracing: do not disable interrupts for trace_clock_local 2009-11-11 23:38:33 -05:00
trace_entries.h hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events 2009-11-08 15:34:42 +01:00
trace_event_profile.c tracing: Use the perf recursion protection from trace event 2009-11-22 09:03:42 +01:00
trace_events.c Merge branch 'perf/core' into perf/probes 2009-10-23 08:23:20 +02:00
trace_events_filter.c tracing/filters: Fix to make system filter work 2009-10-29 08:53:20 +01:00
trace_export.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-05 15:30:21 -08:00
trace_functions.c tracing: switch function prints from %pf to %ps 2009-09-17 15:53:40 -04:00
trace_functions_graph.c tracing: Fix function graph trace_pipe to properly display failed entries 2009-12-09 14:09:06 -05:00
trace_hw_branches.c tracing: fix warning on kernel/trace/trace_branch.c andtrace_hw_branches.c 2009-10-07 21:52:03 -04:00
trace_irqsoff.c tracing: do not update tracing_max_latency when tracer is stopped 2009-09-12 21:45:17 -04:00
trace_kprobe.c trace_kprobes: Fix a memory leak bug and check kstrdup() return value 2009-12-01 08:19:59 +01:00
trace_ksym.c hw-breakpoints: Use struct perf_event_attr to define kernel breakpoints 2009-11-27 06:22:59 +01:00
trace_mmiotrace.c tracing: add filter event logic to special, mmiotrace and boot tracers 2009-09-12 23:34:04 -04:00
trace_nop.c tracing/ftrace: make nop-tracer use polling wait for events on pipe 2009-03-23 09:22:15 +01:00
trace_output.c tracing: Add full state to trace_seq 2009-12-09 14:05:49 -05:00
trace_output.h tracing: consolidate code between trace_output.c and trace_function_graph.c 2009-09-11 14:24:13 -04:00
trace_printk.c tracing: Remove markers 2009-09-18 21:22:08 +02:00
trace_sched_switch.c tracing: pass around ring buffer instead of tracer 2009-09-04 18:59:39 -04:00
trace_sched_wakeup.c tracing: do not update tracing_max_latency when tracer is stopped 2009-09-12 21:45:17 -04:00
trace_selftest.c ksym_tracer: Remove KSYM_SELFTEST_ENTRY 2009-11-08 16:21:01 +01:00
trace_selftest_dynamic.c
trace_stack.c sysctl: remove "struct file *" argument of ->proc_handler 2009-09-24 07:21:04 -07:00
trace_stat.c trace_stat: Fix missing entry in stat file 2009-08-17 11:25:09 +02:00
trace_stat.h tracing/stat: Add stat_release() callback 2009-07-10 12:14:05 +02:00
trace_syscalls.c trace_syscalls: Remove unused syscall_name_to_nr() 2009-12-01 17:33:31 +01:00
trace_sysprof.c Merge branch 'timers-for-linus-migration' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-15 10:06:19 -07:00
trace_workqueue.c tracing/workqueues: Add refcnt to struct cpu_workqueue_stats 2009-07-10 12:14:07 +02:00