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Re: [Xen-ia64-devel] [PATCH 0/16] make xenheap configurable unpinning xe

To: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
Subject: Re: [Xen-ia64-devel] [PATCH 0/16] make xenheap configurable unpinning xenheap
From: Alex Williamson <alex.williamson@xxxxxx>
Date: Tue, 08 Jan 2008 17:25:53 -0700
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On Mon, 2008-01-07 at 16:52 +0900, Isaku Yamahata wrote:
> Presumably benchmarks should be done to confirm that the performance degrade
> is acceptable.

Hi Isaku,

   I tried this patchset, but I can't get xenheap_megabytes to work.  I
tried 32, 128, 256 and they all hit:


in start_kernel().  Does it work for you?  I also ran some kernel build
tests to get an idea of the performance hit.  A UP PV domain was less
that 1% over my previous tests and an HVM domains was less that 1/4%
over previous.  I may be into the noise of my test results, but it does
seem indicate that there is a small hit.  If we can boot more vCPUs and
bigger systems though, it may be a reasonable trade-off.  Thanks,


Alex Williamson                             HP Open Source & Linux Org.

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