Re: [RFC PATCH 0/2] libtraceevent/perf: Add support for trace-cmd plugins

[Steven Rostedt <rostedt@goodmis.org>]

[ I'm tired of getting error messages from sending to some stranger at
weisbec@gmail.com, I might as well send it to someone I know. Someone
with an 'f' ]


On Tue, 2012-06-19 at 10:40 +0900, Namhyung Kim wrote:
> On Mon, 18 Jun 2012 21:26:02 -0400, Steven Rostedt wrote:
> > On Tue, 2012-06-19 at 10:11 +0900, Namhyung Kim wrote:
> >
> >> > trace-cmd report -N
> >> > [...]
> >> >              kvm-6172  [000] 14669573.114126: kvm_entry:            vcpu 0
> >> >              kvm-6172  [000] 14669573.114127: kvm_exit:             [FAILED TO PARSE] exit_reason=30 guest_rip=0xffff357a isa=1 info1=217841672 info2=0
> >> >              kvm-6172  [000] 14669573.114130: kvm_emulate_insn:     [FAILED TO PARSE] rip=4294915450 csbase=0 len=1 insn=ì[ÃWVS<89>Ã<89>Öš^Gu^Q^O^E flags=5 failed=0
> >> >              kvm-6172  [000] 14669573.114130: kvm_pio:              pio_read at 0xcfc size 1 count 1
> >> >              kvm-6172  [000] 14669573.114131: kvm_userspace_exit:   reason KVM_EXIT_IO (2)
> >> >              kvm-6172  [000] 14669573.114134: kvm_entry:            vcpu 0
> >> >
> >> 

> Ok. Then how about using __print_hex() for __print_insn? AFAICS
> ftrace_print_hex_seq() looks almost same as __print_insn() and as it's a
> generic function we can add its handler in libtraceevnt.

We can be a bit better at the raw print, sure. Here's the format that's
there:

	field:__u64 rip;	offset:16;	size:8;	signed:0;
	field:__u32 csbase;	offset:24;	size:4;	signed:0;
	field:__u8 len;	offset:28;	size:1;	signed:0;
	field:__u8 insn[15];	offset:29;	size:15;	signed:0;
	field:__u8 flags;	offset:44;	size:1;	signed:0;
	field:__u8 failed;	offset:45;	size:1;	signed:0;

It treated __u* as decimal numbers, but it also saw that insn[15] was an
array, and with single bytes at that. So it thought it was a string, and
tried to print it out as such.

We can change the heuristics of this to make it more readable.

-- Steve