Hello, On Wed, Feb 05, 2014 at 10:17:42AM +0100, Stanislaw Gruszka wrote: > What are selection criteria when choosing between system_wq or > system_power_efficient_wq on drivers ? IOW if I would be writing > a new driver which workqueue should I use and when ? Yeah, it's a bit ad-hoc at the moment. The original intention was just marking the ones which can be shown to have noticeable power impacts which weren't expected to be too many but we may now have an self-feeding feedback loop growing new usages, likely somewhat overzealously and be better off making things more generic. > I think that should be driver independent, at least for most of drivers. > If system have to run in low power mode, system_power_efficient_wq > should be chosen automatically by schedule_work(), otherwise when high > performance is more important schedule_work() should use system_wq. The problem there is that system_wq has traditionally guaranteed per-cpu execution. It can't automatically be switched to unbound behavior. The best long term solution would be isolating the users which depend on per-cpu behavior and mark them specially rather than the other way around that we're doing now, making per-cpu guarantee the special case rather than the norm. That's gonna take a lot of auditing tho. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
