Re: [PATCH] nvme: add cond_resched() to nvme_complete_batch()

Keith Busch
2023-05-15T20:41:01Z

On Tue, May 02, 2023 at 08:54:12PM +0800, jiweisun126@126.com wrote:
> From: Jiwei Sun <sunjw10@lenovo.com>
>
> A soft lockup issue will be triggered when do fio test on a 448-core
> server, such as the following warning:

...

> According to the above two logs, we can know the nvme_irq() cost too much
> time, in the above case, about 4.8 second. And we can also know that the
> main bottlenecks is in the competition for the spin lock pool->lock.

The most recent 6.4-rc has included a significant changeset to the pool
allocator that may show a considerable difference in pool->lock timing.
It would be interesting to hear if it changes your observation with your
448-core setup. Would you be able to re-run your experiements that
produced the soft lockup with this kernel on that machine?