linux/tools/perf/trace
Arnaldo Carvalho de Melo 728db19886 perf beauty: Introduce strtoul() for x86 MSRs
Continuing from the previous cset comment, now that filter expression
works:

  # perf trace -e msr:* --filter="msr!=FS_BASE && msr != IA32_TSC_DEADLINE && msr != 0x830 && msr != 0x83f && msr !=IA32_SPEC_CTRL" --filter-pids 3750
     0.000 Timer/5033 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
     0.009 Timer/5033 msr:write_msr(msr: LSTAR, val: -1398800368)
     0.010 Timer/5033 msr:write_msr(msr: TSC_AUX, val: 4)
     0.050 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
    45.661 gnome-terminal/12595 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
    45.672 gnome-terminal/12595 msr:write_msr(msr: LSTAR, val: -1398800368)
    45.675 gnome-terminal/12595 msr:write_msr(msr: TSC_AUX, val: 3)
    54.852 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   130.508 Timer/4050 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
   130.527 Timer/4050 msr:write_msr(msr: LSTAR, val: -1398800368)
   130.531 Timer/4050 msr:write_msr(msr: TSC_AUX, val: 3)
   140.924 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   164.738 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   603.578 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   620.809 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   690.115 JS Watchdog/4259 msr:write_msr(msr: SYSCALL_MASK, val: 292608)
   690.136 JS Watchdog/4259 msr:write_msr(msr: LSTAR, val: -1398800368)
   690.141 JS Watchdog/4259 msr:write_msr(msr: TSC_AUX, val: 3)
   690.186 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
   759.016 :0/0 msr:read_msr(msr: IA32_TSC_ADJUST)
^C[root@quaco ~]#

Or look at the first 3 write_msr events for that IA32_TSC_DEADLINE to learn why
it happens so often:

  # perf trace --max-events=3 --max-stack=8 -e msr:* --filter="msr==IA32_TSC_DEADLINE" --filter-pids 3750
     0.000 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 19296732550862)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       lapic_next_deadline ([kernel.kallsyms])
                                       clockevents_program_event ([kernel.kallsyms])
                                       hrtimer_interrupt ([kernel.kallsyms])
                                       smp_apic_timer_interrupt ([kernel.kallsyms])
                                       apic_timer_interrupt ([kernel.kallsyms])
                                       cpuidle_enter_state ([kernel.kallsyms])
    32.646 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 19296800134158)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       lapic_next_deadline ([kernel.kallsyms])
                                       clockevents_program_event ([kernel.kallsyms])
                                       hrtimer_start_range_ns ([kernel.kallsyms])
                                       tick_nohz_restart_sched_tick ([kernel.kallsyms])
                                       tick_nohz_idle_exit ([kernel.kallsyms])
                                       do_idle ([kernel.kallsyms])
    32.802 :0/0 msr:write_msr(msr: IA32_TSC_DEADLINE, val: 19297507436922)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       lapic_next_deadline ([kernel.kallsyms])
                                       clockevents_program_event ([kernel.kallsyms])
                                       hrtimer_try_to_cancel ([kernel.kallsyms])
                                       hrtimer_cancel ([kernel.kallsyms])
                                       tick_nohz_restart_sched_tick ([kernel.kallsyms])
                                       tick_nohz_idle_exit ([kernel.kallsyms])
  #

And if some of the strings can't be found:

  # trace -e msr:* --filter="msr!=SPECULATIVE_EXECUTION_PROBLEMS_SOLUTION && msr != IA32_TSC_DEADLINE && msr != 0x830 && msr != 0x83f && msr !=IA32_SPEC_CTRL" --filter-pids 3750
  "SPECULATIVE_EXECUTION_PROBLEMS_SOLUTION" not found for "msr" in "msr:read_msr", can't set filter "(msr!=SPECULATIVE_EXECUTION_PROBLEMS_SOLUTION && msr != IA32_TSC_DEADLINE && msr != 0x830 && msr != 0x83f && msr !=IA32_SPEC_CTRL) && (common_pid != 28131 && common_pid != 3750)"
  #

Next step is to automatically wire up the pre-existing strarrays, which there
are quite a few.

The strtoul() methods will be further enhanced to allow for looking at other
arguments in a syscall/tracepoint, just like going from integer to string
(scnprintf methods), so that those "val" lines for the msr tracepoints can be
properly formatted or even resolved into some string.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-4qaai5iqjgefd11k4ddm7qg8@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-10-09 16:25:02 -03:00
..
beauty perf beauty: Introduce strtoul() for x86 MSRs 2019-10-09 16:25:02 -03:00
strace/groups perf trace: Add 'string' event alias to select syscalls with string args 2019-04-01 14:49:24 -03:00