Commit Graph

65 Commits

Author SHA1 Message Date
Linus Torvalds
4aed2fd8e3 Merge branch 'perf-core-for-linus' of 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
2010-08-06 09:30:52 -07:00
Jason Wessel
955b61e597 ftrace,kdb: Extend kdb to be able to dump the ftrace buffer
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>
2010-08-05 09:22:23 -05:00
Frederic Weisbecker
f376bf5ffb tracing: Remove sysprof ftrace plugin
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>
2010-07-20 14:29:46 +02:00
Frederic Weisbecker
5d550467b9 tracing: Remove ksym tracer
The ksym (breakpoint) ftrace plugin has been superseded by perf
tools that are much more poweful to use the cpu breakpoints.
This tracer doesn't bring more feature. It has been deprecated
for a while now, lets remove it.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
2010-07-15 23:59:33 +02:00
Li Zefan
039ca4e74a tracing: Remove kmemtrace ftrace plugin
We have been resisting new ftrace plugins and removing existing
ones, and kmemtrace has been superseded by kmem trace events
and perf-kmem, so we remove it.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
[ remove kmemtrace from the makefile, handle slob too ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2010-06-09 17:31:22 +02:00
Américo Wang
30dbb20e68 tracing: Remove boot tracer
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>
2010-06-08 23:31:28 +02:00
Peter Zijlstra
faa4602e47 x86, perf, bts, mm: Delete the never used BTS-ptrace code
Support for the PMU's BTS features has been upstreamed in
v2.6.32, but we still have the old and disabled ptrace-BTS,
as Linus noticed it not so long ago.

It's buggy: TIF_DEBUGCTLMSR is trampling all over that MSR without
regard for other uses (perf) and doesn't provide the flexibility
needed for perf either.

Its users are ptrace-block-step and ptrace-bts, since ptrace-bts
was never used and ptrace-block-step can be implemented using a
much simpler approach.

So axe all 3000 lines of it. That includes the *locked_memory*()
APIs in mm/mlock.c as well.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Markus Metzger <markus.t.metzger@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20100325135413.938004390@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-26 11:33:55 +01:00
Frederic Weisbecker
97d5a22005 perf: Drop the obsolete profile naming for trace events
Drop the obsolete "profile" naming used by perf for trace events.
Perf can now do more than simple events counting, so generalize
the API naming.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
2010-03-10 14:47:18 +01:00
Li Zefan
07b139c8c8 perf events: Remove CONFIG_EVENT_PROFILE
Quoted from Ingo:

| This reminds me - i think we should eliminate CONFIG_EVENT_PROFILE -
| it's an unnecessary Kconfig complication. If both PERF_EVENTS and
| EVENT_TRACING is enabled we should expose generic tracepoints.
|
| Nor is it limited to event 'profiling', so it has become a misnomer as
| well.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <4B2F1557.2050705@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-28 10:33:06 +01:00
Ingo Molnar
96200591a3 Merge branch 'tracing/hw-breakpoints' into perf/core
Conflicts:
	arch/x86/kernel/kprobes.c
	kernel/trace/Makefile

Merge reason: hw-breakpoints perf integration is looking
              good in testing and in reviews, plus conflicts
              are mounting up - so merge & resolve.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21 14:07:23 +01:00
Masami Hiramatsu
77b44d1b7c tracing/kprobes: Rename Kprobe-tracer to kprobe-event
Rename Kprobes-based event tracer to kprobes-based tracing event
(kprobe-event), since it is not a tracer but an extensible
tracing event interface.

This also changes CONFIG_KPROBE_TRACER to CONFIG_KPROBE_EVENT
and sets it y by default.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
LKML-Reference: <20091104001247.3454.14131.stgit@harusame>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-04 13:02:48 +01:00
Frederic Weisbecker
0f8f86c7bd Merge commit 'perf/core' into perf/hw-breakpoint
Conflicts:
	kernel/Makefile
	kernel/trace/Makefile
	kernel/trace/trace.h
	samples/Makefile

Merge reason: We need to be uptodate with the perf events development
branch because we plan to rewrite the breakpoints API on top of
perf events.
2009-10-18 01:12:33 +02:00
Frederic Weisbecker
d7a4b414ee Merge commit 'linus/master' into tracing/kprobes
Conflicts:
	kernel/trace/Makefile
	kernel/trace/trace.h
	kernel/trace/trace_event_types.h
	kernel/trace/trace_export.c

Merge reason:
	Sync with latest significant tracing core changes.
2009-09-23 23:08:43 +02:00
Arjan van de Ven
6161352142 tracing, perf: Convert the power tracer into an event tracer
This patch converts the existing power tracer into an event tracer,
so that power events (C states and frequency changes) can be
tracked via "perf".

This also removes the perl script that was used to demo the tracer;
its functionality is being replaced entirely with timechart.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090912130542.6d314860@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-19 11:42:12 +02:00
Masami Hiramatsu
413d37d1eb tracing: Add kprobe-based event tracer
Add kprobes-based event tracer on ftrace.

This tracer is similar to the events tracer which is based on Tracepoint
infrastructure. Instead of Tracepoint, this tracer is based on kprobes
(kprobe and kretprobe). It probes anywhere where kprobes can probe(this
 means, all functions body except for __kprobes functions).

Similar to the events tracer, this tracer doesn't need to be activated
via current_tracer, instead of that, just set probe points via
/sys/kernel/debug/tracing/kprobe_events. And you can set filters on each
probe events via /sys/kernel/debug/tracing/events/kprobes/<EVENT>/filter.

This tracer supports following probe arguments for each probe.

  %REG  : Fetch register REG
  sN    : Fetch Nth entry of stack (N >= 0)
  sa    : Fetch stack address.
  @ADDR : Fetch memory at ADDR (ADDR should be in kernel)
  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
  aN    : Fetch function argument. (N >= 0)
  rv    : Fetch return value.
  ra    : Fetch return address.
  +|-offs(FETCHARG) : fetch memory at FETCHARG +|- offs address.

See Documentation/trace/kprobetrace.txt in the next patch for details.

Changes from v13:
 - Support 'sa' for stack address.
 - Use call->data instead of container_of() macro.

[fweisbec@gmail.com: Fixed conflict against latest tracing/core]

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203510.31965.29123.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-27 02:31:54 +02:00
Ingo Molnar
eadb8a091b Merge branch 'linus' into tracing/hw-breakpoints
Conflicts:
	arch/x86/Kconfig
	arch/x86/kernel/traps.c
	arch/x86/power/cpu.c
	arch/x86/power/cpu_32.c
	kernel/Makefile

Semantic conflict:
	arch/x86/kernel/hw_breakpoint.c

Merge reason: Resolve the conflicts, move from put_cpu_no_sched() to
              put_cpu() in arch/x86/kernel/hw_breakpoint.c.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17 12:56:49 +02:00
Li Zefan
55782138e4 tracing/events: convert block trace points to TRACE_EVENT()
TRACE_EVENT is a more generic way to define tracepoints. Doing so adds
these new capabilities to this tracepoint:

  - zero-copy and per-cpu splice() tracing
  - binary tracing without printf overhead
  - structured logging records exposed under /debug/tracing/events
  - trace events embedded in function tracer output and other plugins
  - user-defined, per tracepoint filter expressions
  ...

Cons:

  - no dev_t info for the output of plug, unplug_timer and unplug_io events.
    no dev_t info for getrq and sleeprq events if bio == NULL.
    no dev_t info for rq_abort,...,rq_requeue events if rq->rq_disk == NULL.

    This is mainly because we can't get the deivce from a request queue.
    But this may change in the future.

  - A packet command is converted to a string in TP_assign, not TP_print.
    While blktrace do the convertion just before output.

    Since pc requests should be rather rare, this is not a big issue.

  - In blktrace, an event can have 2 different print formats, but a TRACE_EVENT
    has a unique format, which means we have some unused data in a trace entry.

    The overhead is minimized by using __dynamic_array() instead of __array().

I've benchmarked the ioctl blktrace vs the splice based TRACE_EVENT tracing:

      dd                   dd + ioctl blktrace       dd + TRACE_EVENT (splice)
1     7.36s, 42.7 MB/s     7.50s, 42.0 MB/s          7.41s, 42.5 MB/s
2     7.43s, 42.3 MB/s     7.48s, 42.1 MB/s          7.43s, 42.4 MB/s
3     7.38s, 42.6 MB/s     7.45s, 42.2 MB/s          7.41s, 42.5 MB/s

So the overhead of tracing is very small, and no regression when using
those trace events vs blktrace.

And the binary output of TRACE_EVENT is much smaller than blktrace:

 # ls -l -h
 -rw-r--r-- 1 root root 8.8M 06-09 13:24 sda.blktrace.0
 -rw-r--r-- 1 root root 195K 06-09 13:24 sda.blktrace.1
 -rw-r--r-- 1 root root 2.7M 06-09 13:25 trace_splice.out

Following are some comparisons between TRACE_EVENT and blktrace:

plug:
  kjournald-480   [000]   303.084981: block_plug: [kjournald]
  kjournald-480   [000]   303.084981:   8,0    P   N [kjournald]

unplug_io:
  kblockd/0-118   [000]   300.052973: block_unplug_io: [kblockd/0] 1
  kblockd/0-118   [000]   300.052974:   8,0    U   N [kblockd/0] 1

remap:
  kjournald-480   [000]   303.085042: block_remap: 8,0 W 102736992 + 8 <- (8,8) 33384
  kjournald-480   [000]   303.085043:   8,0    A   W 102736992 + 8 <- (8,8) 33384

bio_backmerge:
  kjournald-480   [000]   303.085086: block_bio_backmerge: 8,0 W 102737032 + 8 [kjournald]
  kjournald-480   [000]   303.085086:   8,0    M   W 102737032 + 8 [kjournald]

getrq:
  kjournald-480   [000]   303.084974: block_getrq: 8,0 W 102736984 + 8 [kjournald]
  kjournald-480   [000]   303.084975:   8,0    G   W 102736984 + 8 [kjournald]

  bash-2066  [001]  1072.953770:   8,0    G   N [bash]
  bash-2066  [001]  1072.953773: block_getrq: 0,0 N 0 + 0 [bash]

rq_complete:
  konsole-2065  [001]   300.053184: block_rq_complete: 8,0 W () 103669040 + 16 [0]
  konsole-2065  [001]   300.053191:   8,0    C   W 103669040 + 16 [0]

  ksoftirqd/1-7   [001]  1072.953811:   8,0    C   N (5a 00 08 00 00 00 00 00 24 00) [0]
  ksoftirqd/1-7   [001]  1072.953813: block_rq_complete: 0,0 N (5a 00 08 00 00 00 00 00 24 00) 0 + 0 [0]

rq_insert:
  kjournald-480   [000]   303.084985: block_rq_insert: 8,0 W 0 () 102736984 + 8 [kjournald]
  kjournald-480   [000]   303.084986:   8,0    I   W 102736984 + 8 [kjournald]

Changelog from v2 -> v3:

- use the newly introduced __dynamic_array().

Changelog from v1 -> v2:

- use __string() instead of __array() to minimize the memory required
  to store hex dump of rq->cmd().

- support large pc requests.

- add missing blk_fill_rwbs_rq() in block_rq_requeue TRACE_EVENT.

- some cleanups.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A2DF669.5070905@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-09 12:34:23 -04:00
K.Prasad
0722db015c hw-breakpoints: ftrace plugin for kernel symbol tracing using HW Breakpoint interfaces
This patch adds an ftrace plugin to detect and profile memory access over kernel
variables. It uses HW Breakpoint interfaces to 'watch memory addresses.

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-06-02 22:47:00 +02:00
Ingo Molnar
0ad5d703c6 Merge branch 'tracing/hw-branch-tracing' into tracing/core
Merge reason: this topic is ready for upstream now. It passed
              Oleg's review and Andrew had no further mm/*
              objections/observations either.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-07 13:36:22 +02:00
Steven Rostedt
5092dbc96f ring-buffer: add benchmark and tester
This patch adds code that can benchmark the ring buffer as well as
test it. This code can be compiled into the kernel (not recommended)
or as a module.

A separate ring buffer is used to not interfer with other users, like
ftrace. It creates a producer and a consumer (option to disable creation
of the consumer) and will run for 10 seconds, then sleep for 10 seconds
and then repeat.

While running, the producer will write 10 byte loads into the ring
buffer with just putting in the current CPU number. The reader will
continually try to read the buffer. The reader will alternate from reading
the buffer via event by event, or by full pages.

The output is a pr_info, thus it will fill up the syslogs.

  Starting ring buffer hammer
  End ring buffer hammer
  Time:     9000349 (usecs)
  Overruns: 12578640
  Read:     5358440  (by events)
  Entries:  0
  Total:    17937080
  Missed:   0
  Hit:      17937080
  Entries per millisec: 1993
  501 ns per entry
  Sleeping for 10 secs
  Starting ring buffer hammer
  End ring buffer hammer
  Time:     9936350 (usecs)
  Overruns: 0
  Read:     28146644  (by pages)
  Entries:  74
  Total:    28146718
  Missed:   0
  Hit:      28146718
  Entries per millisec: 2832
  353 ns per entry
  Sleeping for 10 secs

Time:      is the time the test ran
Overruns:  the number of events that were overwritten and not read
Read:      the number of events read (either by pages or events)
Entries:   the number of entries left in the buffer
                 (the by pages will only read full pages)
Total:     Entries + Read + Overruns
Missed:    the number of entries that failed to write
Hit:       the number of entries that were written

The above example shows that it takes ~353 nanosecs per entry when
there is a reader, reading by pages (and no overruns)

The event by event reader slowed the producer down to 501 nanosecs.

[ Impact: see how changes to the ring buffer affect stability and performance ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-05-06 00:08:50 -04:00
Steven Rostedt
f42c85e74f tracing/events: move the ftrace event tracing code to core
This patch moves the ftrace creation into include/trace/ftrace.h and
simplifies the work of developers in adding new tracepoints.
Just the act of creating the trace points in include/trace and including
define_trace.h will create the events in the debugfs/tracing/events
directory.

This patch removes the need of include/trace/trace_events.h

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-14 12:57:59 -04:00
Ingo Molnar
56449f437a tracing: make the trace clocks available generally
Jeremy Fitzhardinge reported this build failure:

 LD	 .tmp_vmlinux1
 arch/x86/kernel/built-in.o: In function `ds_take_timestamp':
 git/linux/arch/x86/kernel/ds.c:1380: undefined reference to `trace_clock_global'
 git/linux/arch/x86/kernel/ds.c:1380: undefined reference to `trace_clock_global'

Which is due to !CONFIG_TRACING && CONFIG_X86_DS=y.

Expose the trace clock code to CONFIG_X86_DS as well.

[ Unfortunately librarizing doesnt work well - ancient architectures
  with no raw_local_irq_save() primitive break the build. ]

Reported-by: Jeremy Fitzhardinge <jeremy@goop.org>
LKML-Reference: <49E4413F.7070700@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-14 18:35:13 +02:00
Tom Zanussi
5f77a88b3f tracing/infrastructure: separate event tracer from event support
Add a new config option, CONFIG_EVENT_TRACING that gets selected
when CONFIG_TRACING is selected and adds everything needed by the stuff
in trace_export - basically all the event tracing support needed by e.g.
bprint, minus the actual events, which are only included if
CONFIG_EVENT_TRACER is selected.

So CONFIG_EVENT_TRACER can be used to turn on or off the generated events
(what I think of as the 'event tracer'), while CONFIG_EVENT_TRACING turns
on or off the base event tracing support used by both the event tracer and
the other things such as bprint that can't be configured out.

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1239178441.10295.34.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-14 00:00:55 +02:00
Tom Zanussi
7ce7e42499 tracing: add per-event filtering
This patch adds per-event filtering to the event tracing subsystem.

It adds a 'filter' debugfs file to each event directory.  This file can
be written to to set filters; reading from it will display the current
set of filters set for that event.

Basically, any field listed in the 'format' file for an event can be
filtered on (including strings, but not yet other array types) using
either matching ('==') or non-matching ('!=') 'predicates'.  A
'predicate' can be either a single expression:

 # echo pid != 0 > filter

 # cat filter
 pid != 0

or a compound expression of up to 8 sub-expressions combined using '&&'
or '||':

 # echo comm == Xorg > filter
 # echo "&& sig != 29" > filter

 # cat filter
 comm == Xorg
 && sig != 29

Only events having field values matching an expression will be available
in the trace output; non-matching events are discarded.

Note that a compound expression is built up by echoing each
sub-expression separately - it's not the most efficient way to do
things, but it keeps the parser simple and assumes that compound
expressions will be relatively uncommon.  In any case, a subsequent
patch introducing a way to set filters for entire subsystems should
mitigate any need to do this for lots of events.

Setting a filter without an '&&' or '||' clears the previous filter
completely and sets the filter to the new expression:

 # cat filter
 comm == Xorg
 && sig != 29

 # echo comm != Xorg

 # cat filter
 comm != Xorg

To clear a filter, echo 0 to the filter file:

 # echo 0 > filter
 # cat filter
 none

The limit of 8 predicates for a compound expression is arbitrary - for
efficiency, it's implemented as an array of pointers to predicates, and
8 seemed more than enough for any filter...

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237710665.7703.48.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-22 18:38:46 +01:00
Peter Zijlstra
ac199db018 ftrace: event profile hooks
Impact: new tracing infrastructure feature

Provide infrastructure to generate software perf counter events
from tracepoints.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20090319194233.557364871@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-20 10:17:07 +01:00