性能报告显示 CPU 寄存器的值

Question

我关注 this document 并使用 perf record 和 --intr-regs=ax,bx,r15，试图用 PEBS 记录记录额外的 CPU 注册信息。

但是我如何从 perf.data 查看这些信息？原来的command是perf report，只显示了overhead，command，shared object，symbol等几个字段

有什么方法可以显示 CPU regs 的值吗？

Answer 1

我想办法用perf report -D实现了，然后一条条记录找到你需要记录的寄存器名（不过这样好像效率很低..）

或者其他人可以提供更简化的方法？

Answer 2

使用 iregs 字段尝试 perf script 数据转储命令：perf script -F ip,sym,iregs。所有字段 -F 都记录在 tools/perf/builtin-script.c - struct output_option .. all_output_options, and iregs is still here (also OPT_CALLBACK('F', "fields" ... in same file). There is also perf-script.txt documentation - https://github.com/torvalds/linux/blob/master/tools/perf/Documentation/perf-script.txt#L115

的源代码中

-F::
--fields::
    Comma separated list of fields to print. Options are:
    comm, tid, pid, time, cpu, event, trace, ip, sym, dso, addr, symoff,
    srcline, period, iregs, brstack, brstacksym, flags, bpf-output, brstackinsn,
    callindent, insn, insnlen. Field list can be prepended with the type, trace, sw or hw,
    to indicate to which event type the field list applies.

有提交到 linux 内核 git，其中提到标志 --intr-regs。从选项实现开始：

https://github.com/torvalds/linux/search?utf8=%E2%9C%93&q=intr-regs&type=

tools/perf/builtin-record.c OPT_CALLBACK_OPTARG('I', "intr-regs", &record.opts.sample_intr_regs, NULL, "any register",

然后在提交中搜索'sample_intr_regs'：https://github.com/torvalds/linux/search?q=sample_intr_regs&type=Commits

几个提交是关于内核部分和 perf_attr 调试打印。但这有 intr-regs 印刷的例子（2015 年 9 月 1 日） https://github.com/torvalds/linux/commit/532026612455a4a6fd27c1b2e7111263f63218a2

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo: - Add ability to specify to select which registers to record, to reduce the size of perf.data files, and also allow printing the registers in 'perf script': (Stephane Eranian)
  # perf record --intr-regs=AX,SP usleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.016 MB perf.data (8 samples) ]
  # perf script -F ip,sym,iregs | tail -5
   ffffffff8105f42a native_write_msr_safe   AX:0xf    SP:0xffff8802629c3c00
   ffffffff8105f42a native_write_msr_safe   AX:0xf    SP:0xffff8802629c3c00
   ffffffff81761ac0 _raw_spin_lock   AX:0xffff8801bfcf8020    SP:0xffff8802629c3ce8
   ffffffff81202bf8 __vma_adjust_trans_huge   AX:0x7ffc75200000    SP:0xffff8802629c3b30
   ffffffff8122b089 dput   AX:0x101    SP:0xffff8802629c3c78
  #

性能报告显示 CPU 寄存器的值

perf-report show value of CPU register

linux

cpu

intel

linux-kernel

perf