Re: [PATCH v2 0/6] fix test failures on larger core systems

Bruce Richardson
2026-01-21T16:31:27Z

On Mon, Jan 19, 2026 at 05:55:03PM -0800, Stephen Hemminger wrote:
> This series addresses several test failures that occur sporadically on
> systems with many cores (32+), particularly on AMD Zen architectures.
> I think Ferruh may have addressed similar problems in earlier
> releases.
>
> The root causes fall into three categories:
>
> 1. Missing rte_pause() in synchronization spinloops (patch 1)
> Tight spinloops without pause cause SMT thread starvation and
> unpredictable timing behavior.
>
> 2. Fixed iteration counts that don't scale (patch 2)
> The atomic test performs 1M iterations per worker regardless of
> core count. With 32+ cores, contention causes timeout failures.
>
Testing on a 96-core part, I still see timeouts (with -t2, so 20-second
allowed) in mcslock, stack, stack_lf and timer tests. Limiting core counts
for those makes the failures go away, so it's likely the same issue as you
solved here.

/Bruce