Re: [Xen-ia64-devel] [PATCH 0/4] [RFC] performance tuning of vTLB flush

[Alex Williamson <alex.williamson@xxxxxx>]

On Fri, 2006-08-04 at 21:27 +0900, Isaku Yamahata wrote:
> Hi all
> These patches are for performance tuning.
> They are for comment, review and evaluation.
> 
> - per vcpu vhpt
> - tlb tracking
> - deferred page freeing
>   NEW: This patch is incomplete yet. It must be polished more.

   Here are my performance numbers:

System: 2 Cell HP Superdome, 8-way 1.5GHz/6M, 12GB RAM

The test: UP dom0 (2GB, single user mode), 7-way domU (3GB, single user
mode, no network), kernel build time w/ make -j8 (4 runs, 1st run thrown
out, average of other 3 runs)

Stock (cset 10931):

 real: 282.643s
 user: 1733.523s
 sys:  132.650s

Patches applied, TLB tracking NOT enabled (fixed domain.c build):

 real: 282.209s  (0.998)
 user: 1734.533s (1.001)
 sys:  130.253s  (0.982)

Patches applied, TLB tracking enabled:

 real: 288.591s  (1.021)
 user: 1770.453s (1.021)
 sys:  143.297s  (1.080)

So it looks like w/o TLB tracking enabled, the patch is probably within
the noise of my test.  With TLB tracking enabled, there is a small, but
noticeable performance degradation.  Under what conditions might we see
a performance improvement?  Thanks,

        Alex

-- 
Alex Williamson                             HP Open Source & Linux Org.


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