Re: [PATCHv2] Add per-process flag to control thp

[David Rientjes]

On Tue, 6 Aug 2013, Alex Thorlton wrote:

> I've gotten my hands on some of the benchmarks/code that were used to
> originally uncover the performance issues we're seeing.  I'm currently
> trying to separate out the performance issues that are being caused by
> the kernel code from issues involving hardware - the cost of remote
> memory accesses is a bit higher on our systems with node controllers vs.
> glueless QPI/Hypertransport-based systems.  
> 

We've seen some issues where accessing remote hugepages causes performance 
degradations over accessing local pages that affects some workloads, but 
that seems like a mempolicy issue rather than madvise.  You probably want 
local hugepages but not fallback to remote hugepages before allocating 
local pages?  It would be interesting to see /proc/pid/numa_maps and 
/proc/pid/smaps for workloads that don't like thp.
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