perf_link creates a system-wide perf event pinned to CPU 0 (pid=-1, cpu=0)
and also pins the test thread to CPU 0. Under concurrent selftests this
can lead to cross-test interference and CPU 0 contention, making the test
flaky.
Create a per-task perf event instead (pid=0, cpu=-1) and drop CPU pinning
from burn_cpu(). Use barrier() to prevent the burn loop from being
optimized away. Drop the serial_ prefix so the test can run in parallel.
Also remove the stale TODO comment.
Tested:
./test_progs -t perf_link -vv
./test_progs -j$(nproc) -t perf_link -vv
for i in $(seq 1 50); do ./test_progs -j$(nproc) -t perf_link; done
Signed-off-by: Sun Jian <sun.jian.kdev@gmail.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260305084306.283983-1-sun.jian.kdev@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Use the new type-safe wrappers around bpf_obj_get_info_by_fd().
Fix a prog/map mixup in prog_holds_map().
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230214231221.249277-6-iii@linux.ibm.com
Linux kernel may automatically reduce kernel.perf_event_max_sample_rate
value when running tests in parallel on slow systems. Linux kernel checks
against this limit when opening perf event with freq=1 parameter set.
The lower bound is 1000. This patch reduces sample_freq value to 1000
in all BPF tests that use sample_freq to ensure they always can open
perf event.
Signed-off-by: Mykola Lysenko <mykolal@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220308200449.1757478-2-mykolal@fb.com
