Messages in this thread | | | From | Masami Hiramatsu <> | Subject | [PATCH v2 0/3] perf probe: Introduce remote cross-arch probes | Date | Fri, 26 Aug 2016 01:24:10 +0900 |
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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@kernel.org>
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