Re: [PATCH v2 0/3] perf probe: Introduce remote cross-arch probes

[Masami Hiramatsu]

ping?

On Fri, 26 Aug 2016 01:24:10 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> Hi,
> 
> Here is the 2nd version of remote cross-arch probe support on perf-probe.
> V1 is here:
>   https://lkml.org/lkml/2016/8/24/29
> 
> Currently perf-probe doesn't supoort cross/remote target. This means
> we have to cross-build the perf-tools including libraries (elfutils,
> libelf etc.), and to prepare vmlinux with debuginfo which can be 
> accessed from the target machine.
> This requires too much resource for a small embededd device.
> 
> If we can analyze the debuginfo by perf-probe on host machine,
> we do not need to cross-build perf-tools, nor copy vmlinux on the
> device. :)
> 
> For that purpose, this series adds --definition(-D) command for
> perf-probe, which shows trace event definition instead of adding
> it in running kernel, according to Arnaldo's comment.
> Using -D with --vmlinux(or -k)=OFFLINE-VMLINUX, perf-probe reads
> the vmlinux architecture and show definition with correct
> dwarf-registers.
> 
>   perf probe -k <cross-vmlinux> -D <probe-point> <arguments>
> 
> Here is an example:
>   -----
>   $ perf probe --vmlinux=./vmlinux-arm --definition 'do_sys_open $params'
>   p:probe/do_sys_open do_sys_open+0 dfd=%r5:s32 filename=%r1:u32 flags=%r6:s32 mode=%r3:u16
>   -----
> Here, we can get probe/do_sys_open event by "copy & paste" the
> definition to target-machine's debugfs/tracing/kprobe_events.
> 
> Note that it shows definition with direct symbol name instead of
> _text+offset. It is treated as an offline module.
> 
> Thanks,
> ---
> 
> Masami Hiramatsu (3):
>       perf-probe: Show trace event definition
>       perf-probe: Ignore vmlinux buildid if offline kernel is given
>       perf-probe: Support probing on offline cross-arch binary
> 
> 
>  tools/perf/Documentation/perf-probe.txt            |    9 +++
>  tools/perf/arch/arm/include/dwarf-regs-table.h     |    9 +++
>  tools/perf/arch/arm64/include/dwarf-regs-table.h   |   13 +++++
>  tools/perf/arch/powerpc/include/dwarf-regs-table.h |   27 ++++++++++
>  tools/perf/arch/s390/include/dwarf-regs-table.h    |    8 +++
>  tools/perf/arch/sh/include/dwarf-regs-table.h      |   25 +++++++++
>  tools/perf/arch/sparc/include/dwarf-regs-table.h   |   18 +++++++
>  tools/perf/arch/x86/include/dwarf-regs-table.h     |   14 +++++
>  tools/perf/arch/xtensa/include/dwarf-regs-table.h  |    8 +++
>  tools/perf/builtin-probe.c                         |   34 ++++++++++--
>  tools/perf/util/Build                              |    1 
>  tools/perf/util/dwarf-regs.c                       |   55 ++++++++++++++++++++
>  tools/perf/util/include/dwarf-regs.h               |    6 ++
>  tools/perf/util/probe-event.c                      |   50 ++++++++++++++++++
>  tools/perf/util/probe-event.h                      |    1 
>  tools/perf/util/probe-finder.c                     |   27 ++++++----
>  tools/perf/util/probe-finder.h                     |    1 
>  tools/perf/util/symbol-elf.c                       |    2 -
>  18 files changed, 289 insertions(+), 19 deletions(-)
>  create mode 100644 tools/perf/arch/arm/include/dwarf-regs-table.h
>  create mode 100644 tools/perf/arch/arm64/include/dwarf-regs-table.h
>  create mode 100644 tools/perf/arch/powerpc/include/dwarf-regs-table.h
>  create mode 100644 tools/perf/arch/s390/include/dwarf-regs-table.h
>  create mode 100644 tools/perf/arch/sh/include/dwarf-regs-table.h
>  create mode 100644 tools/perf/arch/sparc/include/dwarf-regs-table.h
>  create mode 100644 tools/perf/arch/x86/include/dwarf-regs-table.h
>  create mode 100644 tools/perf/arch/xtensa/include/dwarf-regs-table.h
>  create mode 100644 tools/perf/util/dwarf-regs.c
> 
> --
> Masami Hiramatsu (Linaro Ltd.) <mhiramat@xxxxxxxxxx>


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>