linux/kernel/trace
Vaibhav Nagarnaik c64e148a3b trace: Add ring buffer stats to measure rate of events
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>
2011-08-30 12:27:45 -04:00
..
blktrace.c block: make unplug timer trace event correspond to the schedule() unplug 2011-04-16 13:51:05 +02:00
ftrace.c Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core 2011-07-21 09:32:40 +02:00
Kconfig ftrace: Build without frame pointers on Microblaze 2011-04-21 09:06:24 -04:00
Makefile tracing/filter: Add startup tests for events filter 2011-08-19 14:35:59 -04:00
power-traces.c perf: Clean up power events by introducing new, more generic ones 2011-01-04 08:16:54 +01:00
ring_buffer_benchmark.c tracing: Use NUMA allocation for per-cpu ring buffer pages 2011-06-14 22:04:39 -04:00
ring_buffer.c trace: Add ring buffer stats to measure rate of events 2011-08-30 12:27:45 -04:00
trace_branch.c tracing: Allow events to share their print functions 2010-05-14 14:20:32 -04:00
trace_clock.c Fix common misspellings 2011-03-31 11:26:23 -03:00
trace_entries.h tracing: Have dynamic size event stack traces 2011-07-14 16:36:53 -04:00
trace_event_perf.c tracing: New flag to allow non privileged users to use a trace event 2010-11-18 14:37:40 +01:00
trace_events_filter_test.h tracing/filter: Add startup tests for events filter 2011-08-19 14:35:59 -04:00
trace_events_filter.c tracing: Add preempt disable for filter self test 2011-08-30 12:27:07 -04:00
trace_events.c Merge branch 'perf/urgent' into perf/core 2011-07-21 09:29:21 +02:00
trace_export.c tracing: Replace trace_event struct array with pointer array 2011-02-02 21:37:13 -05:00
trace_functions_graph.c tracing: Still trace filtered irq functions when irq trace is disabled 2011-07-07 22:26:27 -04:00
trace_functions.c ftrace: Fix regression of :mod:module function enabling 2011-07-07 11:30:08 -04:00
trace_irqsoff.c tracing, function_graph: Remove dependency of abstime and duration fields on latency 2011-06-14 22:48:47 -04:00
trace_kdb.c kdb,ftdump: Remove reference to internal kdb include 2010-10-22 15:34:11 -05:00
trace_kprobe.c tracing/kprobe: Update symbol reference when loading module 2011-07-15 15:45:32 -04:00
trace_mmiotrace.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
trace_nop.c
trace_output.c tracing: Have dynamic size event stack traces 2011-07-14 16:36:53 -04:00
trace_output.h tracing: Allow events to share their print functions 2010-05-14 14:20:32 -04:00
trace_printk.c tracing: Clean up tb_fmt to not give faulty compile warning 2011-08-10 20:36:32 -04:00
trace_sched_switch.c tracing: Remove obsolete sched_switch tracer 2011-02-08 17:14:56 -05:00
trace_sched_wakeup.c tracing, function_graph: Remove dependency of abstime and duration fields on latency 2011-06-14 22:48:47 -04:00
trace_selftest_dynamic.c ftrace: Add self-tests for multiple function trace users 2011-05-18 19:24:51 -04:00
trace_selftest.c ftrace: Add self-tests for multiple function trace users 2011-05-18 19:24:51 -04:00
trace_stack.c tracing: Convert to kstrtoul_from_user 2011-06-14 22:48:50 -04:00
trace_stat.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
trace_stat.h
trace_syscalls.c tracing/syscalls: Early terminate search for sys_ni_syscall 2011-02-07 21:30:14 -05:00
trace_workqueue.c jump label: Initialize workqueue tracepoints *before* they are registered 2010-09-22 16:30:03 -04:00
trace.c trace: Add ring buffer stats to measure rate of events 2011-08-30 12:27:45 -04:00
trace.h tracing/filter: Add startup tests for events filter 2011-08-19 14:35:59 -04:00