From mboxrd@z Thu Jan  1 00:00:00 1970
From: "David S. Ahern" <daahern@cisco.com>
Subject: Re: performance with guests running 2.4
 kernels	(specifically RHEL3)
Date: Wed, 30 Apr 2008 07:39:53 -0600
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Cc: kvm-devel <kvm-devel@lists.sourceforge.net>,
	Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@qumranet.com>
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Avi Kivity wrote:
> David S. Ahern wrote:
>> Another tidbit for you guys as I make my way through various
>> permutations:
>> I installed the RHEL3 hugemem kernel and the guest behavior is *much*
>> better.
>> System time still has some regular hiccups that are higher than xen
>> and esx
>> (e.g., 1 minute samples out of 5 show system time between 10 and 15%),
>> but
>> overall guest behavior is good with the hugemem kernel.
>>
>>   
> 
> Wait, the amount of info here is overwhelming. Let's stick with the
> current kernel (32-bit, HIGHMEM4G, right?)
> 
> Did you get any traces with bypass_guest_pf=0? That may show more info.
> 

My preference is to stick with the "standard", 32-bit RHEL3 kernel in the guest.
My point in the last email was that the hugemem kernel shows a remarkable
difference (it uses 3-levels of page tables right?). I was hoping that would
ring a bell with someone.

Adding bypass_guest_pf=0 did not improve the situation. Did you want anything
particular with that setting -- like a RIP summary or a summary of exit-entry
cycles?

david

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