> On Mon, Feb 01, 2021 at 08:17:59AM +0000, Avri Altman wrote: > > > > > > On Mon, Feb 01, 2021 at 07:51:19AM +0000, Avri Altman wrote: > > > > > > > > > > On Mon, Feb 01, 2021 at 07:12:53AM +0000, Avri Altman wrote: > > > > > > > > +#define WORK_PENDING 0 > > > > > > > > +#define ACTIVATION_THRSHLD 4 /* 4 IOs */ > > > > > > > Rather than fixing it with macro, how about using sysfs and make it > > > > > > > configurable? > > > > > > Yes. > > > > > > I will add a patch making all the logic configurable. > > > > > > As all those are hpb-related parameters, I think module parameters > are > > > > > more adequate. > > > > > > > > > > No, this is not the 1990's, please never add new module parameters to > > > > > drivers. If not for the basic problem of they do not work on a > > > > > per-device basis, but on a per-driver basis, which is what you almost > > > > > never want. > > > > OK. > > > > > > > > > > > > > > But why would you want to change this value, why can't the driver > "just > > > > > work" and not need manual intervention? > > > > It is. > > > > But those are a knobs each vendor may want to tweak, > > > > So it'll be optimized with its internal device's implementation. > > > > > > > > Tweaking the parameters, as well as the entire logic, is really an endless > > > task. > > > > Some logic works better for some scenarios, while falling behind on > others. > > > > > > Shouldn't the hardware know how to handle this dynamically? If not, how > > > is a user going to know? > > There is one "brain". > > It is either in the device - in device mode, Or in the host - in host mode > control. > > The "brain" decides which region is active, thus carrying the physical address > along with the logical - > > minimizing context switches in the device's RAM. > > > > There can be up to N active regions. > > Activation and deactivation has its overhead. > > So basically it is a constraint-optimization problem. > > So how do you solve it? And how would you expect a user to solve it if > the kernel can not? > > You better document the heck out of these configuration options :) Yes. Will do. Thanks, Avri
