[DTrace-devel] [PATCH 1/5] test: fbt return0: work on quiet systems

[Kris Van Hees]

On Mon, Oct 06, 2025 at 04:28:24PM +0100, Nick Alcock wrote:
> These two tests probe on sys_poll and just hope something calls it.
> On sufficiently quiet systems, nothing does.
> 
> Define a trivial trigger to do so.

Why not change the probe to be on hrtimer_nanosleep and use periodic_output
as trigger, rather than adding another trigger executable?

> Signed-off-by: Nick Alcock <nick.alcock at oracle.com>
> ---
>  test/triggers/Build                          |  2 +-
>  test/triggers/fbt-tst-poll.c                 | 23 ++++++++++++++++++++
>  test/unittest/fbtprovider/tst.return0.d      |  6 ++++-
>  test/unittest/providers/rawfbt/tst.return0.d |  6 ++++-
>  4 files changed, 34 insertions(+), 3 deletions(-)
>  create mode 100644 test/triggers/fbt-tst-poll.c
> 
> diff --git a/test/triggers/Build b/test/triggers/Build
> index 4ff5002a853ed..bd6b0510ba003 100644
> --- a/test/triggers/Build
> +++ b/test/triggers/Build
> @@ -4,7 +4,7 @@
>  # http://oss.oracle.com/licenses/upl.
>  
>  EXTERNAL_64BIT_TRIGGERS = testprobe readwholedir mmap bogus-ioctl open delaydie futex \
> -    periodic_output \
> +    periodic_output fbt-tst-poll \
>      pid-tst-args1 pid-tst-float pid-tst-fork pid-tst-gcc \
>      pid-tst-ret1 pid-tst-ret2 pid-tst-vfork pid-tst-weak1 pid-tst-weak2 \
>      proc-tst-sigwait proc-tst-omp proc-tst-pthread-exec profile-tst-ufuncsort \
> diff --git a/test/triggers/fbt-tst-poll.c b/test/triggers/fbt-tst-poll.c
> new file mode 100644
> index 0000000000000..8b1e72eddd258
> --- /dev/null
> +++ b/test/triggers/fbt-tst-poll.c
> @@ -0,0 +1,23 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * Simply loop, polling stdin for something that cannot happen until killed.
> + */
> +
> +#include <poll.h>
> +
> +int
> +main(int argc, char **argv)
> +{
> +	struct pollfd fd = {0};
> +
> +	fd.fd = 0;
> +	fd.events = POLLPRI;
> +	for (;;)
> +		poll(&fd, 1, 100);
> +}
> diff --git a/test/unittest/fbtprovider/tst.return0.d b/test/unittest/fbtprovider/tst.return0.d
> index 0b7091b320904..78a82ffde7473 100644
> --- a/test/unittest/fbtprovider/tst.return0.d
> +++ b/test/unittest/fbtprovider/tst.return0.d
> @@ -11,11 +11,15 @@
>   * SECTION: FBT Provider/Probe arguments
>   */
>  
> +/* @@trigger: fbt-tst-poll */
> +/* @@trigger-timing: before */
> +/* @@runtest-opts: $_pid */
> +
>  #pragma D option quiet
>  #pragma D option statusrate=10ms
>  
>  fbt::do_sys_poll:return
> -/arg1 == 0/
> +/pid == $1 && arg1 == 0/
>  {
>  	printf("%s %x returned 0", probefunc, arg0);
>  	exit(0);
> diff --git a/test/unittest/providers/rawfbt/tst.return0.d b/test/unittest/providers/rawfbt/tst.return0.d
> index 0146d684f1033..915830c800b70 100644
> --- a/test/unittest/providers/rawfbt/tst.return0.d
> +++ b/test/unittest/providers/rawfbt/tst.return0.d
> @@ -9,11 +9,15 @@
>   * ASSERTION: simple rawfbt provider arg0 and probefunc print test.
>   */
>  
> +/* @@trigger: fbt-tst-poll */
> +/* @@trigger-timing: before */
> +/* @@runtest-opts: $_pid */
> +
>  #pragma D option quiet
>  #pragma D option statusrate=10ms
>  
>  rawfbt::do_sys_poll:return
> -/arg1 == 0/
> +/pid == $1 && arg1 == 0/
>  {
>  	printf("%s %x returned 0", probefunc, arg0);
>  	exit(0);
> 
> base-commit: 877fcdeb25b370be182d51f27fb4bd8e4f739fb1
> -- 
> 2.51.0.284.g117bcb8de7
>