On Wed, 18 Jul 2018, Johannes Thumshirn wrote: > On Wed, Jul 18, 2018 at 08:06:10PM +0800, Ming Lei wrote: > > IMO the problem isn't related with slow or quick device, it is related with > > the system, especially when it cares about power consumption, such as > > mobile phone, or laptop or servers with lots of disks attached. And we know > > it is often to see some fast disks shipped in laptop, such as NVMe, or other > > SSD. > > Yes but you're only taking locally attached devices into account. > This is very likely harmful on sd devices attached to a > SRP/FC/iSCSI/SAS Target in a SAN environment. These can be really fast > and people investing this money are likely to not like additional > performance penalties. As one extra reminder... People who care about extreme performance can perfectly well disable CONFIG_PM in their kernels. That should remove any overhead due to runtime PM. Alan Stern
