Re: [PATCH 0/5] Intel Code/Data Prioritization(CDP) feature enabling

[Chao Peng <chao.p.peng@linux.intel.com>]

On Wed, Sep 02, 2015 at 01:08:33PM +0100, Andrew Cooper wrote:
> On 02/09/15 09:27, He Chen wrote:
> > Hi all,
> >
> > Code/Data Prioritization(CDP) is offered in Intel Broadwell and later server
> > platforms, which is an extension of CAT. CDP enables isolation and separate
> > prioritization of code and data fetches to the L3 cache in a software
> > configurable manner, which can enable workload prioritization and tuning of
> > cache capacity to the characteristics of the workload. CDP extends Cache
> > Allocation Technology (CAT) by providing separate code and data capacity bit
> > masks(CBM) per Class of Service (COS). CDP is used on VM basis in the Xen
> > implementation.
> >
> > More information about CDP, please refer to Intel SDM, Volumn 3, section 17.16
> > http://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-manual-325462.pdf
> >
> > This patch series enables CDP feature in Xen based on CAT code, including
> > extending CBM operation functions and introducing new commands to enable/disable
> > CDP dynamically. For all the changes, please see in each patch.
> >
> > This patchset has been tested on Intel Broadwell server platform.
> >
> > To make this patchset better, any comment or suggestion is welcomed, I would
> > really appreciate it.
> 
> I have taken a look at patches 1-3.  For the most part, it looks good.
> 
> The main point I have is on patch 2, as to whether it is sensible to
> permit enabling/disabling cdp at runtime.  I suggest that it is not
> sensible, and should be a command line parameter instead.
> 
> If this is agreed as ok going forwards, patches 3 through 5 should
> become rather more simple.

I guess it would be OK, and a helpful change.
Let's see the next version.

Chao