On Wed, 4 Feb 2026 22:52:11 +0800
Donglin Peng <[email protected]> wrote:
> > > I have trace-cmd reading BTF now (just haven't officially released it) and
> > > doing an extract and reading the trace.dat file is much faster than
> > > reading
> > > the trace file with arguments. I'll need to implement the enum logic too
> > > in
> > > libtraceevent.
> >
> > If you mean to do pretty printing of the trace in user space then +1 from
> > me.
> >
> > I don't like sorting enums either in resolve_btfid, pahole or kernel.
> > Sorted BTF by name was ok, since it doesn't change original semantics.
> > While sorting enums by value gets us to the grey zone where
> > the sequence of enum names in vmlinux.h becomes different than in dwarf.
>
> Thanks, I agreed.
BTW, I just officially released trace-cmd v3.4 (where you can see whats
new in that release here[1]).
The biggest change is that it saves the BTF file in the trace.dat file
and parses it on the report (it requires libtraceevent v1.9):
~# trace-cmd record -p function_graph -O funcgraph-args -g do_sys_openat2
[..]
~# trace-cmd report
trace-cmd-50935 [002] ...1. 3490.518138: funcgraph_entry:
| do_sys_openat2(dfd=4294967196, filename=0x557bb9e3ee10,
how=0xffff88815220fea8) {
trace-cmd-50935 [002] ...1. 3490.518141: funcgraph_entry:
| getname_flags(filename=0x557bb9e3ee10, flags=0) {
trace-cmd-50935 [002] ...1. 3490.518142: funcgraph_entry:
| getname_flags.part.0(filename=0x557bb9e3ee10, flags=0) {
trace-cmd-50935 [002] ...1. 3490.518143: funcgraph_entry:
| kmem_cache_alloc_noprof(s=0xffff888106c7e000, gfpflags=0xcc0) {
trace-cmd-50935 [002] ...1. 3490.518145: funcgraph_entry:
| stack_trace_save(store=0xffff88815220fac8, size=0x40,
skipnr=0x0) {
trace-cmd-50935 [002] ...1. 3490.518147: funcgraph_entry:
| arch_stack_walk(consume_entry=0xffffffff94d9dfe0,
cookie=0xffff88815220fa58, task=0xffff88812d4c3580, regs=0x0) {
trace-cmd-50935 [002] ...1. 3490.518148: funcgraph_entry:
| __unwind_start(state=0xffff88815220f988,
task=0xffff88812d4c3580, regs=0x0, first_frame=0xffff88815220fa28) {
trace-cmd-50935 [002] ...1. 3490.518149: funcgraph_entry: 1.518
us | get_stack_info(stack=0xffff88815220f938,
task=0xffff88812d4c3580, info=0xffff88815220f988,
visit_mask=0xffff88815220f9a8); (ret=0x0)
trace-cmd-50935 [002] ...1. 3490.518152: funcgraph_entry:
| unwind_next_frame(state=0xffff88815220f988) {
trace-cmd-50935 [002] ...1. 3490.518153: funcgraph_entry: 0.951
us | __rcu_read_lock(); (ret=0xffff88812d4c3580)
-- Steve
[1]
https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/tag/?h=trace-cmd-v3.4
