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[PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: Frederic Weisbecker <fweisbec at gmail dot com>, Steven Rostedt <rostedt at goodmis dot org>, Ingo Molnar <mingo at elte dot hu>, lkml<linux-kernel at vger dot kernel dot org>
- Cc: Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Andi Kleen <ak at linux dot intel dot com>, Christoph Hellwig <hch at infradead dot org>, "Frank Ch. Eigler" <fche at redhat dot com>, "H. Peter Anvin" <hpa at zytor dot com>, Jason Baron <jbaron at redhat dot com>, Jim Keniston <jkenisto at us dot ibm dot com>, "K.Prasad" <prasad at linux dot vnet dot ibm dot com>, Lai Jiangshan <laijs at cn dot fujitsu dot com>, Li Zefan <lizf at cn dot fujitsu dot com>, Peter Zijlstra <peterz at infradead dot org>, Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>, Tom Zanussi <tzanussi at gmail dot com>, systemtap<systemtap at sources dot redhat dot com>, DLE<dle-develop at lists dot sourceforge dot net>
- Date: Thu, 10 Sep 2009 19:52:58 -0400
- Subject: [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support
Hi Frederic,
This series fixes bugs and upgrades kprobe-based event tracer
as a dynamic event tracer on ftrace/perf tools. This also enhances
tracer output format to show each argument name and event name on
each entry.
With this series, users can add trace events dynamically on ftrace
and use those events with perf tools as below.
(Step.1) Define new events under new group
$ echo p:mygroup/myprobe do_sys_open dfd=a0 filename=a1 flags=a2 mode=a3 \
> /debug/tracing/kprobes_events
$ echo r:mygroup/myretprobe do_sys_open rv >> /debug/tracing/kprobes_events
$ cat /debug/tracing/kprobes_events
p:myprobe do_sys_open+0 dfd=a0 filename=a1 flags=a2 mode=a3
r:myretprobe do_sys_open+0 rv=rv
(You can see that each argument has its name.)
(Step.2) Perf shows new events
$ perf list
...
mygroup:myretprobe [Tracepoint event]
mygroup:myprobe [Tracepoint event]
...
(Step.3) Record events with perf
$ perf record -f -e mygroup:myprobe:record -F 1 -a ls
...
[ perf record: Captured and wrote 0.081 MB perf.data (~3544 samples) ]
(Step.4) Perf trace shows the result
$ perf trace
version = 0.5
perf-1405 [000] 0.000000: myprobe: (c04b0a5c) dfd=ffffff9c filename=810d3f7 flags=98800 mode=1
perf-1405 [000] 0.000000: myprobe: (c04b0a5c) dfd=ffffff9c filename=bff7650c flags=8000 mode=1b6
perf-1405 [000] 0.000000: myprobe: (c04b0a5c) dfd=ffffff9c filename=bff7650c flags=98800 mode=bff7450c
perf-1405 [000] 0.000000: myprobe: (c04b0a5c) dfd=ffffff9c filename=bff7650c flags=8000 mode=1b6
(Step.5) You can also use return probes.
$ perf record -f -e mygroup:myretprobe:record -F 1 -a ls
...
[ perf record: Captured and wrote 0.081 MB perf.data (~3544 samples) ]
$ perf trace
version = 0.5
perf-1408 [000] 0.000000: myretprobe: (c04b0a5c <- c04b0b7d) rv=b
perf-1408 [000] 0.000000: myretprobe: (c04b0a5c <- c04b0b7d) rv=c
perf-1408 [000] 0.000000: myretprobe: (c04b0a5c <- c04b0b7d) rv=d
perf-1408 [000] 0.000000: myretprobe: (c04b0a5c <- c04b0b7d) rv=c
TODO:
- Implement perf kprobe command to help defining new probes.
Thank you,
---
Masami Hiramatsu (7):
tracing/kprobes: Support custom subsystem for each kprobe event
tracing/kprobes: Show event name in trace output
tracing/kprobes: Add argument name support
tracing/kprobes: Add event profiling support
tracing/kprobes: Cleanup kprobe tracer code.
tracing/kprobes: Fix probe offset to be unsigned
x86/ptrace: Fix regs_get_argument_nth() to add correct offset
Documentation/trace/kprobetrace.txt | 65 +++---
arch/x86/kernel/ptrace.c | 2
kernel/trace/trace_kprobe.c | 369 +++++++++++++++++++++++------------
3 files changed, 274 insertions(+), 162 deletions(-)
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com