Hi Shinichiro,
---- On Wed, 25 Jun 2025 20:20:50 +0800 Shinichiro Kawasaki <shinichiro.kawasaki@xxxxxxx> wrote ---
> Cc+: Johaness,
>
> On Jun 24, 2025 / 20:10, Li Chen wrote:
> > From: Li Chen <chenl311@xxxxxxxxxxxxxxx>
> >
> > The current hard-coded timeout for block/005 and 008 is 900 s. On large systems
> > (e.g. 256 C) the test spawns one fio job per CPU and therefore
> > issues 1 GiB of random I/O per job. Total workload scales linearly with
> > the CPU-count, so the original 900 s window is often insufficient for
> > high-core machines and causes false failures:
> >
> > fio did not finish after 900 seconds!
> >
> > To keep the logic simple while avoiding unnecessary test flakiness, bump
> > the timeout to 1800 s whenever the system has more than 128 online CPUs.
> > Smaller systems continue to use the original 900 s limit.
>
> Hello Li, thank you for the patch, and pointing out the problem. Your idea to
> extend the timeout can be a solution. But I wonder we may need to extend the
> timeout value again when we have more CPUs in the future.
>
> On the other hand, I can think of another idea. How about to cap the number of
> jobs with a specific number? According to the blktests commit 8fc7ca8300cd
> ("tests: use nproc to get number of CPUs for fio jobs"), the fio option
> --numjobs="${nproc}" in _run_fio_rand_io() was introduced for the workloads
> which "just want some IO". So, I think it is allowed to cap the numjobs with
> some number, such as 128. Based on this idea, I created the patch below. Could
> you try out if this approach avoids the problem on your system?
>
>
> diff --git a/common/fio b/common/fio
> index 91f4b23..f4965db 100644
> --- a/common/fio
> +++ b/common/fio
> @@ -204,10 +204,12 @@ _fio_opts_to_min_io() {
> # Wrapper around _run_fio used if you need some I/O but don't really care much
> # about the details
> _run_fio_rand_io() {
> - local bs
> + local bs nr_jobs
>
> bs=$(_fio_opts_to_min_io "$@") || return 1
> - _run_fio --bs="$bs" --rw=randread --norandommap --numjobs="$(nproc)" \
> + nr_jobs=$(nproc)
> + ((nr_jobs > 128)) && nr_jobs=128
> + _run_fio --bs="$bs" --rw=randread --norandommap --numjobs="$nr_jobs" \
> --name=reads --direct=1 "$@"
Yes, this looks better. I'll try this patch when the machine is available, likely next week.
Regards,
Li
