Re: [PATCH 1/2] rtlwifi: Fix improve function 'rtl_addr_delay()' in core.c

[Larry Finger]

On 02/04/2016 03:48 AM, David Laight wrote:
> From: Larry Finger
> > Sent: 03 February 2016 19:45
> ...
> > The performance will depend on where you satisfy the condition. All switch cases
> > have the same execution time, but in the if .. else if .. else form, the earlier
> > tests execute more quickly. I'm not sure that one can make any blanket statement
> > about performance. Certainly, the switch version will be larger. For a switch
> > with 8 cases plus default, the object code if 43 bytes larger than the nested
> > ifs in a test program that I created. That is a significant penalty.
>
> There is also the penalty of the (likely) data cache miss reading the jump table.
> But given this code is all about generating a variable delay the execution
> speed is probably irrelevant.
>
> It would be much more interesting if the delay could be changed for sleeps.

Unfortunately, sleeping is not possible for the routines that call rtl_addr_delay().

Larry