Li, Aubrey wrote:
> The following webrev added turbo mode observability support of the kernel 
> part.
> http://cr.opensolaris.org/~aubrey/turbo-kernel-part/
> It is against [rev #8756] of pad-gate.
> 
> I almost re-write Vinay's patch, instead of implementing the ioctl() of 
> cpudrv, I think
> kstat for observability is better.
> 
> Before I start the powertop part of turbo mode observability support, I 
> really appreciate
> your any comments and suggestions.
> 
> Thanks,
> -Aubrey
> 
> Experiment as follows:
> ===================
> 1) after my system boots:
> -----------------------------------------------------------
> aubrey at aubrey-power:~$ kstat -m speedstep -i 7
> module: speedstep                       instance: 7     
> name:   turbo                           class:    misc
>         crtime                          42.052402205
>         snaptime                        80.926871283
>         turbo acnt                      6172692478
>         turbo mcnt                      6246417685
>         turbo support                   1
> ----------------------------------------------------------
> Here, we know turbo mode is supported.
> mcnt: increments in proportion to a fixed frequency when in P0
> acnt:  increments in proportion to actual performance when in P0.
> 
> 2) now bind a while(1) process to processor 7.
> ------------------------------------------------------------
> aubrey at aubrey-power:~$ pfexec pbind -b 7 480 
> process id 480: was not bound, now 7
> ------------------------------------------------------------
> 
> 3) let while(1) run for several minutes
> 
> 4) check turbo info again
> ------------------------------------------------------------
> aubrey at aubrey-power:~$ kstat -m speedstep -i 7
> module: speedstep                       instance: 7     
> name:   turbo                           class:    misc
>         crtime                          42.052402205
>         snaptime                        540.775843325
>         turbo acnt                      1108972992925
>         turbo mcnt                      1062698922865
>         turbo support                   1 
> ------------------------------------------------------------
> It looks like turbo took effect. acnt/mcnt shows 4% performance boost.


Very nice, Aubrey. Much cleaner implementation.

How about adding a kstat item for the actual performance boost?

Rafael

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