Re: [PATCHv3 bpf-next 5/5] selftests/bpf: Add usdt trigger bench

[Jiri Olsa]

On Wed, Feb 11, 2026 at 01:45:15PM -0800, Andrii Nakryiko wrote:
> On Wed, Feb 11, 2026 at 12:49 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> >
> > Adding usdt trigger bench for usdt:
> >  trig-usdt_nop - usdt on top of nop1 instruction
> >  trig-usdt_nop_combo - usdt on top of nop1/nop5 combo
> >
> > Adding it to benchs/run_bench_uprobes.sh script.
> >
> > Example run on x86_64 kernel with uprobe syscall:
> >
> >   # ./benchs/run_bench_uprobes.sh
> >   usermode-count :  152.507 ± 0.098M/s
> >   syscall-count  :   14.309 ± 0.093M/s
> >   uprobe-nop     :    3.190 ± 0.012M/s
> >   uprobe-push    :    3.057 ± 0.004M/s
> >   uprobe-ret     :    1.095 ± 0.009M/s
> >   uprobe-nop5    :    7.305 ± 0.034M/s
> >   uretprobe-nop  :    2.175 ± 0.005M/s
> >   uretprobe-push :    2.109 ± 0.003M/s
> >   uretprobe-ret  :    0.945 ± 0.002M/s
> >   uretprobe-nop5 :    3.530 ± 0.006M/s
> >   usdt_nop       :    3.235 ± 0.008M/s   <-- added
> >   usdt_nop_combo :    7.511 ± 0.045M/s   <-- added
> 
> consistency, usdt-nop. And for nop_combo I'd use usdt-nop5, that combo
> doesn't matter for performance beyond the fact that we have nop5 there

ok

SNIP

> > +static void usdt_setup(const char *name)
> > +{
> > +       struct bpf_link *link;
> > +       int err;
> > +
> > +       setup_libbpf();
> > +
> > +       ctx.skel = trigger_bench__open();
> > +       if (!ctx.skel) {
> > +               fprintf(stderr, "failed to open skeleton\n");
> > +               exit(1);
> > +       }
> > +
> > +       bpf_program__set_autoload(ctx.skel->progs.bench_trigger_usdt, true);
> > +
> > +       err = trigger_bench__load(ctx.skel);
> > +       if (err) {
> > +               fprintf(stderr, "failed to load skeleton\n");
> > +               exit(1);
> > +       }
> > +
> > +       link = bpf_program__attach_usdt(ctx.skel->progs.bench_trigger_usdt,
> > +                                       0 /*self*/, "/proc/self/exe",
> > +                                       "optimized_attach", name, NULL);
> > +       if (libbpf_get_error(link)) {
> > +               fprintf(stderr, "failed to attach optimized_attach:%s usdt probe\n", name);
> > +               exit(1);
> > +       }
> > +       ctx.skel->links.bench_trigger_usdt = link;
> > +}
> > +
> > +static void usdt_nop_setup(void)
> > +{
> > +       usdt_setup("usdt_1");
> > +}
> > +
> > +static void usdt_nop_combo_setup(void)
> > +{
> > +       usdt_setup("usdt_2");
> > +}
> >  #endif
> >
> >  const struct bench bench_trig_syscall_count = {
> > @@ -609,4 +667,6 @@ BENCH_TRIG_USERMODE(uprobe_nop5, nop5, "uprobe-nop5");
> >  BENCH_TRIG_USERMODE(uretprobe_nop5, nop5, "uretprobe-nop5");
> >  BENCH_TRIG_USERMODE(uprobe_multi_nop5, nop5, "uprobe-multi-nop5");
> >  BENCH_TRIG_USERMODE(uretprobe_multi_nop5, nop5, "uretprobe-multi-nop5");
> > +BENCH_TRIG_USERMODE(usdt_nop, usdt_nop, "usdt_nop");
> > +BENCH_TRIG_USERMODE(usdt_nop_combo, usdt_nop_combo, "usdt_nop_combo");
> >  #endif
> > diff --git a/tools/testing/selftests/bpf/benchs/run_bench_uprobes.sh b/tools/testing/selftests/bpf/benchs/run_bench_uprobes.sh
> > index 03f55405484b..3656676d99d2 100755
> > --- a/tools/testing/selftests/bpf/benchs/run_bench_uprobes.sh
> > +++ b/tools/testing/selftests/bpf/benchs/run_bench_uprobes.sh
> > @@ -2,7 +2,7 @@
> >
> >  set -eufo pipefail
> >
> > -for i in usermode-count syscall-count {uprobe,uretprobe}-{nop,push,ret,nop5}
> > +for i in usermode-count syscall-count {uprobe,uretprobe}-{nop,push,ret,nop5} usdt_nop usdt_nop_combo
> 
> usdt_{nop,nop5}, consistency ;)

ook, will change

thanks,
jirka