[Xen-ia64-devel] [PATCH][RFC] per vcpu VHPT

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

Hi.

I implemented per vcpu VHPT for non-VTi domain.
The motivation is to alleviate vcpu migration cost between physical cpus
with credit scheduler.
If more than one vcpu of same domain, VHPT needs to be flushed every
vcpu switch. I'd like to avoid this scenario.
The patch is for discussion and performance evaluation. Not for commit. 


I checked the mailing list archives and found the thread
Xen/ia64 - global or per VP VHPT
http://lists.xensource.com/archives/html/xen-devel/2005-04/msg01002.html

The conclustion at that time isn't concluded. 
(At least my understanding. Because the thread was very long to follow. 
So I might be wrong, correct me.)
With this patch, we can measure the performance and descide to include
this patch or discard the idea.


This patch introduces compile time optoin,  xen_ia64_pervcpu_vhpt=y,
to enable this feature and xen boot time option,  pervcpu_vhpt=0
to disable per vcpu vhpt allocation.
The patch depends on tlb tracking patch which I sent before.
I attached these patches for convinience.

Thanks
-- 
yamahata

Attachment: 10701:c654d462c448_import_linux_hash.h.patch
Description: Text document

Attachment: 10702:cb0aa2b2e180_tlb_track.patch
Description: Text document

Attachment: 10703:a56d48066373_pervcpu_vhpt.patch
Description: Text document

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