Re: [PATCH 00/11] Use global pages with PTI

Dave Hansen
2018-03-27T16:32:35Z

On 03/27/2018 06:36 AM, Thomas Gleixner wrote:
>> User Time Kernel Time Clock Elapsed
>> Baseline ( 0 GLB PTEs) 803.79 67.77 237.30
>> w/series (28 GLB PTEs) 807.70 (+0.7%) 68.07 (+0.7%) 238.07 (+0.3%)
>>
>> Without PCIDs, it behaves the way I would expect.
> What's the performance benefit on !PCID systems? And I mean systems which
> actually do not have PCID, not a PCID system with 'nopcid' on the command
> line.

Do you have something in mind for this? Basically *all* of the servers
that I have access to have PCID because they are newer than ~7 years old.

That leaves *some* Ivybridge and earlier desktops, Atoms and AMD
systems. Atoms are going to be the easiest thing to get my hands on,
but I tend to shy away from them for performance work.