kernel/tools/testing/selftests/sched_ext, branch master

sched_ext/selftests: Fix format specifier and buffer length in file_write_long()

2026-03-04T22:07:43Z

Use %ld (not %lu) for signed long, and pass the actual string length returned by sprintf() to write_text() instead of sizeof(buf). Signed-off-by: Cheng-Yang Chou Signed-off-by: Tejun Heo

selftests/sched_ext: Fix peek_dsq.bpf.c compile error for clang 17

2026-03-03T08:00:34Z

When compiling sched_ext selftests using clang 17.0.6, it raised compiler crash and build error: Error at line 68: Unsupport signed division for DAG: 0x55b2f9a60240: i64 = sdiv 0x55b2f9a609b0, Constant:i64<100>, peek_dsq.bpf.c:68:25 @[ peek_dsq.bpf.c:95:4 @[ peek_dsq.bpf.c:169:8 @[ peek _dsq.bpf.c:140:6 ] ] ]Please convert to unsigned div/mod After digging, it's not a compiler error, clang supported Signed division only when using -mcpu=v4, while we use -mcpu=v3 currently, the better way is to use unsigned div, see [1] for details. [1] https://github.com/llvm/llvm-project/issues/70433 Signed-off-by: Zhao Mengmeng Reviewed-by: Andrea Righi Signed-off-by: Tejun Heo

selftests/sched_ext: Add -fms-extensions to bpf build flags

2026-03-03T08:00:31Z

Similar to commit 835a50753579 ("selftests/bpf: Add -fms-extensions to bpf build flags") and commit 639f58a0f480 ("bpftool: Fix build warnings due to MS extensions") Fix "declaration does not declare anything" warning by using -fms-extensions and -Wno-microsoft-anon-tag flags to build bpf programs that #include "vmlinux.h" Signed-off-by: Zhao Mengmeng Reviewed-by: Andrea Righi Signed-off-by: Tejun Heo

selftests/sched_ext: Remove duplicated unistd.h include in rt_stall.c

2026-02-23T17:45:39Z

The header is included twice in rt_stall.c. Remove the redundant inclusion to clean up the code. Signed-off-by: Cheng-Yang Chou Signed-off-by: Tejun Heo

selftests/sched_ext: Fix unused-result warning for read()

2026-02-23T17:45:10Z

The read() call in run_test() triggers a warn_unused_result compiler warning, which breaks the build under -Werror. Check the return value of read() and exit the child process on failure to satisfy the compiler and handle pipe read errors. Reviewed-by: Andrea Righi Signed-off-by: Cheng-Yang Chou Signed-off-by: Tejun Heo

selftests/sched_ext: Abort test loop on signal

2026-02-23T17:19:13Z

The runner sets exit_req on SIGINT/SIGTERM but ignores it during the main loop. This prevents users from cleanly interrupting a test run. Check exit_req each iteration to safely break out on exit signals. Signed-off-by: Cheng-Yang Chou Acked-by: Andrea Righi Signed-off-by: Tejun Heo

selftests/sched_ext: Fix rt_stall flaky failure

2026-02-13T19:09:39Z

The rt_stall test measures the runtime ratio between an EXT and an RT task pinned to the same CPU, verifying that the deadline server prevents RT tasks from starving SCHED_EXT tasks. It expects the EXT task to get at least 4% of CPU time. The test is flaky because sched_stress_test() calls sleep(RUN_TIME) immediately after fork(), without waiting for the RT child to complete its setup (set_affinity + set_sched). If the RT child experiences scheduling latency before completing setup, that delay eats into the measurement window: the RT child runs for less than RUN_TIME seconds, and the EXT task's measured ratio drops below the 4% threshold. For example, in the failing CI run [1]: EXT=0.140s RT=4.750s total=4.890s (expected ~5.0s) ratio=2.86% < 4% → FAIL The 110ms gap (5.0 - 4.89) corresponds to the RT child's setup time being counted inside the measurement window, during which fewer deadline server ticks fire for the EXT task. Fix by using pipes to synchronize: each child signals the parent after completing its setup, and the parent waits for both signals before starting sleep(RUN_TIME). This ensures the measurement window only counts time when both tasks are fully configured and competing. [1] https://github.com/kernel-patches/bpf/actions/runs/21961895809/job/63442490449 Fixes: be621a76341c ("selftests/sched_ext: Add test for sched_ext dl_server") Assisted-by: claude-opus-4-6-v1 Signed-off-by: Ihor Solodrai Reviewed-by: Andrea Righi Signed-off-by: Tejun Heo

Merge tag 'sched_ext-for-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext

2026-02-11T21:35:24Z

Pull sched_ext updates from Tejun Heo: - Move C example schedulers back from the external scx repo to tools/sched_ext as the authoritative source. scx_userland and scx_pair are returning while scx_sdt (BPF arena-based task data management) is new. These schedulers will be dropped from the external repo. - Improve error reporting by adding scx_bpf_error() calls when DSQ creation fails across all in-tree schedulers - Avoid redundant irq_work_queue() calls in destroy_dsq() by only queueing when llist_add() indicates an empty list - Fix flaky init_enable_count selftest by properly synchronizing pre-forked children using a pipe instead of sleep() * tag 'sched_ext-for-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: selftests/sched_ext: Fix init_enable_count flakiness tools/sched_ext: Fix data header access during free in scx_sdt tools/sched_ext: Add error logging for dsq creation failures in remaining schedulers tools/sched_ext: add arena based scheduler tools/sched_ext: add scx_pair scheduler tools/sched_ext: add scx_userland scheduler sched_ext: Add error logging for dsq creation failures sched_ext: Avoid multiple irq_work_queue() calls in destroy_dsq()

selftests/sched_ext: Add test for DL server total_bw consistency

2026-02-03T11:04:18Z

Add a new kselftest to verify that the total_bw value in /sys/kernel/debug/sched/debug remains consistent across all CPUs under different sched_ext BPF program states: 1. Before a BPF scheduler is loaded 2. While a BPF scheduler is loaded and active 3. After a BPF scheduler is unloaded The test runs CPU stress threads to ensure DL server bandwidth values stabilize before checking consistency. This helps catch potential issues with DL server bandwidth accounting during sched_ext transitions. Co-developed-by: Andrea Righi Signed-off-by: Andrea Righi Signed-off-by: Joel Fernandes Signed-off-by: Peter Zijlstra (Intel) Tested-by: Christian Loehle Link: https://patch.msgid.link/20260126100050.3854740-8-arighi@nvidia.com

selftests/sched_ext: Add test for sched_ext dl_server

2026-02-03T11:04:18Z

Add a selftest to validate the correct behavior of the deadline server for the ext_sched_class. Co-developed-by: Joel Fernandes Signed-off-by: Joel Fernandes Signed-off-by: Andrea Righi Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Emil Tsalapatis Tested-by: Christian Loehle Link: https://patch.msgid.link/20260126100050.3854740-7-arighi@nvidia.com