WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-ia64-devel

RE: [Xen-ia64-devel] [PATCH] [Resend]Enable hash vtlb

To: "Alex Williamson" <alex.williamson@xxxxxx>
Subject: RE: [Xen-ia64-devel] [PATCH] [Resend]Enable hash vtlb
From: "Xu, Anthony" <anthony.xu@xxxxxxxxx>
Date: Tue, 11 Apr 2006 09:25:25 +0800
Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Mon, 10 Apr 2006 18:25:57 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-ia64-devel-request@lists.xensource.com?subject=help>
List-id: Discussion of the ia64 port of Xen <xen-ia64-devel.lists.xensource.com>
List-post: <mailto:xen-ia64-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcZcsWsZ0avbpmAaSIu0EKdzAK9yowAVNyow
Thread-topic: [Xen-ia64-devel] [PATCH] [Resend]Enable hash vtlb
Hi Alex,

I'll kill off all daemons on native and Dom0, and I'll try
to enlarge memory on Dom0 and DomU.
I'll send out the data later.

Thanks,
Anthony


>From: Alex Williamson 
>Sent: 2006?4?10? 23:14
>To: Xu, Anthony
>Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>Subject: RE: [Xen-ia64-devel] [PATCH] [Resend]Enable hash vtlb
>
>On Mon, 2006-04-10 at 23:01 +0800, Xu, Anthony wrote:
>
>> If we configure domU with memory 256MB, domU will complain "at least 256M
>> is needed."
>> Yes there should a best ratio of memory size of domU and size of VHPT.
>
>My tests are:
>
>dom0: boot w/ dom0_mem=768M, kill off all daemons, build
>domU: boot w/ default dom0 mem (512MB), kill all daemons in dom0,
>specify 768M memory from domU, boot domU, kill all domU daemons, build
>
>256MB certainly isn't enough memory to have a worthwhile kernel build
>benchmark.
>
>> >   I don't understand this result.  I was surprised to see domU perform
>> >better than dom0 in my testing, but I can't see how domU could perform
>> >better than bare metal.  Perhaps 512MB is insufficient for kernel
>> >builds.  You may be disproportionately benefiting from dom0's buffer
>> >cache.
>> >
>> I think there maybe two reasons.
>> 1. As you said, domU benefits from dom0's buffer cache. There are somewhat
>> parallel executions. DomU is response of compilation, Dom0 is response of
>> read/write of disk.
>> 2. The services running on Dom0 or DomU are less than that on native machine.
>
>   Services can also be stopped on the native machine.  I did this in my
>test case.  I think it's very possible that 512MB is not a sufficient
>amount of memory for a valid test.  768MB may not be enough either.  To
>properly benchmark this change we need to have the entire working set of
>the test fit in memory (preferably we'd do the builds out of a tmpfs
>mount to avoid I/O entirely).  If we have extra activity, like swapping
>or text getting pushed out of buffer cache and reloaded, anything we can
>read into the results is suspect.  Thanks,
>
>       Alex
>
>--
>Alex Williamson                             HP Linux & Open Source Lab

_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel