On 3/6/26 16:10, Juri Lelli wrote: > Add a comprehensive utility library for SCHED_DEADLINE scheduler tests. > This library provides reusable helper functions that simplify test > implementation and reduce code duplication across the test suite. > > The utility library provides scheduling operations that wrap the > sched_setattr and sched_getattr syscalls for setting and querying > SCHED_DEADLINE parameters. These include dl_set_sched_attr() for > configuring deadline parameters, dl_get_sched_attr() for querying > scheduling attributes, dl_get_policy() for reading the policy from > /proc, and dl_is_deadline_task() for checking if a task is using > SCHED_DEADLINE. The library uses system headers for struct sched_attr > to avoid redefinition conflicts and provides full control over > SCHED_DEADLINE parameters. > > Bandwidth management helpers allow tests to work within system > constraints. The dl_get_rt_bandwidth() function reads RT bandwidth > settings from /proc, while dl_calc_max_bandwidth_percent() calculates > the available bandwidth for deadline tasks based on current system > configuration. > > Process management functions simplify creating and managing test > workloads. The dl_create_cpuhog() function forks and schedules a cpuhog > process by creating a child process, executing the cpuhog binary, and > setting SCHED_DEADLINE policy on the child PID after fork. It waits for > the child to start before configuring the scheduling policy. Supporting > functions include dl_cleanup_cpuhog() for terminating processes, > dl_find_cpuhogs() for locating running instances, and dl_wait_for_pid() > for synchronizing with process startup. > > CPU topology helpers enable tests that manipulate CPU hotplug state. > These include dl_get_online_cpus() for counting available CPUs, > dl_get_hotpluggable_cpus() for identifying which CPUs can be > hotplugged, dl_cpu_online() and dl_cpu_offline() for controlling > hotplug state, and dl_is_cpu_online() for checking current status. > > Time conversion utilities provide convenient transformations between > different time units. These include dl_ms_to_ns() and dl_us_to_ns() > for converting to nanoseconds, and dl_ns_to_ms() and dl_ns_to_us() for > converting from nanoseconds. > > The library also includes the cpuhog helper program, which performs > busy looping to consume CPU cycles. This provides a controllable > workload for testing scheduler behavior under various deadline > configurations. > > Assisted-by: Claude Code: claude-sonnet-4-5@20250929 > Signed-off-by: Juri Lelli <[email protected]> > --- > tools/testing/selftests/sched/deadline/Makefile | 14 +- > tools/testing/selftests/sched/deadline/cpuhog.c | 107 ++++++++ > tools/testing/selftests/sched/deadline/dl_util.c | 335 > +++++++++++++++++++++++ > tools/testing/selftests/sched/deadline/dl_util.h | 227 +++++++++++++++ > 4 files changed, 680 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/sched/deadline/Makefile > b/tools/testing/selftests/sched/deadline/Makefile > index fd57794f1a543..ea3fdfbef459e 100644 > --- a/tools/testing/selftests/sched/deadline/Makefile > +++ b/tools/testing/selftests/sched/deadline/Makefile > @@ -1,6 +1,6 @@ > # SPDX-License-Identifier: GPL-2.0 > > -TEST_GEN_PROGS := runner > +TEST_GEN_PROGS := runner cpuhog >
This runs cpuhog as a test as well which prints misleading timeouts.
