[Intel-gfx] [PATCH] [v2] intel_frequency: A tool to manipulate Intel GPU frequency

[Ben Widawsky]

On Wed, Jan 14, 2015 at 09:42:24AM -0800, O'Rourke, Tom wrote:
> On Tue, Jan 13, 2015 at 02:36:56PM -0800, Ben Widawsky wrote:
> > On Tue, Jan 13, 2015 at 09:19:04PM +0000, O'Rourke, Tom wrote:
> > > >Sent: Sunday, January 11, 2015 7:48 PM
> > > >To: Widawsky, Benjamin
> > > >Cc: Intel GFX
> > > >Subject: Re: [Intel-gfx] [PATCH] [v2] intel_frequency: A tool to manipulate Intel
> > > >GPU frequency
> > > >
> > > >On Sun, Jan 11, 2015 at 07:35:21PM -0800, Ben Widawsky wrote:
> > > >> WARNING: very minimally tested
> > > >>
> > > >> In general you should not need this tool. It's primary purpose is for
> > > >> benchmarking, and for debugging performance issues.
> > > >
> > > >I noticed the "it's" vs "its" on v1, but forgot to fix it. IT'S fixed locally
> > > >though.
> > > >
> > > >>
> > > >> For many kernel releases now sysfs has supported reading and writing the GPU
> > > >> frequency. Therefore, this tool provides no new functionality. What it does
> > > >> provide is an easy to package (for distros) tool that handles the most common
> > > >> scenarios.
> > > [TOR:] This is a nice tool.  
> > > I am concerned that this tool may be confusing RP1 frequency with RPe (Efficient) frequency.  On many platforms, these are not the same thing. 
> > > Thanks,
> > > Tom O'Rourke
> > > 
> > 
> > Any platform other than BYT/CHV?
> 
> [TOR:] I am thinking about Haswell and Broadwell.  The RP1
> value can be read from RP_STATE_CAP while the RPe value can
> be read from PCU mailbox.  Do we need to add a sysfs entry
> for RPe?
> 

Yeah - I didn't know it existed. Let's add that. Updating the tool afterward is
easy. Do we ever want Rp1?

[snip]