Re: [PATCH] brcmfmac: Set SDIO workqueue as WQ_HIGHPRI

On August 17, 2021 8:28:23 PM Tejun Heo [off-list ref] wrote:

Hello,

On Tue, Aug 17, 2021 at 02:21:55PM -0400, Sean Anderson wrote:

quoted

quoted

While I understand the obvious gain it seems like a wrong move to me. What 
if all workqueues in the kernel would start using this flag? I bet the gain 
above would be negated and all are equal in the eyes of .. the kernel

Is there an official policy on what counts as high-priority? Using some
very-scientific methodology [1], it seems like most high-priority
workqueues are in drivers/net and fs. Making these queues high-priority
seems to be commonplace. For example, in fe101716c7c9 ("rtw88: replace
tx tasklet with work queue"), Po-Hao Huang remarks:

I think this is actually a good candidate for HIGHPRI. As you noted, stuff
which interacts with hardware in latency sensitive manner with impact on
observable performance is one of the common use cases. The alternatives
would be doing it from hard/softirqs which are higher priorities anyway.

Hi, Tejun

Thanks for the explanation.

Regards,
Arend