From: Tejun Heo <tj@kernel.org>
To: Michal Blaszczyk <michalblk@google.com>
Cc: David Vernet <void@manifault.com>,
Andrea Righi <arighi@nvidia.com>,
Changwoo Min <changwoo@igalia.com>,
sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] selftests/sched_ext: Fix flaky ddsp failure tests on busy systems
Date: Fri, 14 Aug 2026 12:34:54 -1000 [thread overview]
Message-ID: <9a87b991e47916a87c00c1277e00066d@kernel.org> (raw)
In-Reply-To: <20260811141358.2767765-1-michalblk@google.com>
On Tue, Aug 11, 2026 at 02:13:58PM +0000, Michal Blaszczyk wrote:
> The ddsp_vtimelocal_fail and ddsp_bogus_dsq_fail tests skip calling
> scx_bpf_dsq_insert_vtime() if scx_bpf_pick_idle_cpu() fails to find
> an idle CPU (returns -1). On loaded systems, this results in the tests
> skipping the very assertions they are meant to verify.
>
> Eliminate this flakiness by falling back to prev_cpu if no idle CPU is
> found, ensuring the illegal dispatch operations are unconditionally
> attempted and tested.
Applied to sched_ext/for-7.3 with the description updated to say that
scx_bpf_pick_idle_cpu() returns a negative error code on failure rather
than -1.
Thanks.
--
tejun
prev parent reply other threads:[~2026-08-14 22:34 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-11 14:13 [PATCH] selftests/sched_ext: Fix flaky ddsp failure tests on busy systems Michal Blaszczyk
2026-08-14 22:34 ` Tejun Heo [this message]
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