Re: [PATCH 02/13] wifi: mwifiex: Use default @max_active for workqueues

Tejun Heo
2023-05-10T18:16:14Z

Hello,

On Wed, May 10, 2023 at 11:09:55AM -0700, Brian Norris wrote:
> I'll admit, the workqueue documentation sounds a bit like "max_active ==
> 1 + WQ_UNBOUND" is what we want ("one work item [...] active at any
> given time"), but that's more of my misunderstanding than anything --
> each work item can only be active in a single context at any given time,
> so that note is talking about distinct (i.e., more than 1) work items.

Yeah, a future patch is gonna change the semantics a bit and I'll update the
doc to be clearer.

> While I'm here: we're still debugging what's affecting WiFi performance
> on some of our WiFi systems, but it's possible I'll be turning some of
> these into struct kthread_worker instead. We can cross that bridge
> (including potential conflicts) if/when we come to it though.

Can you elaborate the performance problem you're seeing? I'm working on a
major update for workqueue to improve its locality behavior, so if you're
experiencing issues on CPUs w/ multiple L3 caches, it'd be a good test case.

Thanks.

--
tejun