Messages in this thread |  | | | From | Masami Hiramatsu <> | | Subject | [RFC PATCH tracing/kprobes 0/5] tracing/kprobes, perf: perf kprobe support | | Date | Fri, 25 Sep 2009 12:14:30 -0700 |
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Hi,
These patches introduce perf kprobe command and update kprobe-tracer. perf kprobe command allows you to add new probe points by C line number and local variable names.
Usage ----- perf kprobe [<options>] -P PROBEDEF [-P PROBEDEF ...] -k, --vmlinux <file> vmlinux/module pathname -r, --release <rel> kernel release -P, --probe <p|r:[GRP/]NAME,FUNC[+OFFS][@SRC]|@SRC:LINE,ARG[,ARG,...]> probe point definition, where p: kprobe probe r: kretprobe probe GRP: Group name (optional) NAME: Event name FUNC: Function name OFFS: Offset from function entry (in byte) SRC: Source code path LINE: Line number ARG: Probe argument (local variable name or kprobe-tracer argument format is supported.) Examples -------- 1) Add a new kprobe probe on a line of C source code. ./perf kprobe -P 'p:myprobe,@fs/bio.c:162,bv,idx' Adding new event: p:myprobe bvec_free_bs+17 bv=%bx idx=%cx 2) Add a new kretprobe probe on a function return. ./perf kprobe -P 'r:myretprobe,vfs_read,$rv' Adding new event: r:myretprobe vfs_read+0 $rv
3) Check it in the perf list. ./perf list ... rNNN [raw hardware event descriptor]
kprobes:myprobe [Tracepoint event] kprobes:myretprobe [Tracepoint event] skb:kfree_skb [Tracepoint event] ...
4) Check its format
$ cat /sys/kernel/debug/tracing/events/kprobes/myprobe/format name: myprobe ID: 687 format: field:unsigned short common_type; offset:0; size:2; field:unsigned char common_flags; offset:2; size:1; field:unsigned char common_preempt_count; offset:3; size:1; field:int common_pid; offset:4; size:4; field:int common_lock_depth; offset:8; size:4;
field: unsigned long __probe_ip; offset:12; size:4; field: int __probe_nargs; offset:16; size:4; field: unsigned long bv; offset:20; size:4; field: unsigned long idx; offset:24; size:4;
print fmt: "(%lx) bv=%lx idx=%lx", REC->__probe_ip, REC->bv, REC->idx
Syntax Issue ------------ This version picks '-P event-definition' syntax, but I think '-p event -a arg' is also possible. I'd like to ask you which you like or support both?
TODO ---- There are still many enhancements required for catching up 'tracing side' of systemtap. I think it should be done one by one. I hope that systemtap developers cooperate with us on this development. - Support sys_perf_counter_open (non-root) - Type support - Non-auto static variable - Fields of data structure (var->field) - Bit fields - Array (var[N]) - Dynamic array indexing (var[var2]) - String/dynamic arrays (var:string, var[N..M]) - Force Type casting ((type)var) - Non-inline search - libdw, libdwfl
Thank you,
--- Masami Hiramatsu (5): perf: kprobe command supports without libdwarf perf: Support perf kprobe command for kprobe-event setup helper tracing/kprobes: Rename fixed field name tracing/kprobes: Avoid field name confliction tracing/kprobes: Rename special variables syntax
Documentation/trace/kprobetrace.txt | 10 - kernel/trace/trace_kprobe.c | 124 +++++- tools/perf/Makefile | 10 + tools/perf/builtin-kprobe.c | 340 +++++++++++++++++ tools/perf/builtin.h | 1 tools/perf/perf.c | 1 tools/perf/util/probe-finder.c | 684 +++++++++++++++++++++++++++++++++++ tools/perf/util/probe-finder.h | 70 ++++ 8 files changed, 1200 insertions(+), 40 deletions(-) create mode 100644 tools/perf/builtin-kprobe.c create mode 100644 tools/perf/util/probe-finder.c create mode 100644 tools/perf/util/probe-finder.h -- Masami Hiramatsu
Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division
e-mail: mhiramat@redhat.com
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