From: Avi Kivity <avi@redhat.com>
To: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v5 0/9] KVM: fast page fault
Date: Thu, 24 May 2012 10:19:23 +0300 [thread overview]
Message-ID: <4FBDE0FB.3040100@redhat.com> (raw)
In-Reply-To: <4FBDD5CA.9020906@linux.vnet.ibm.com>
On 05/24/2012 09:31 AM, Xiao Guangrong wrote:
> On 05/23/2012 07:37 PM, Avi Kivity wrote:
>
>> On 05/23/2012 11:51 AM, Xiao Guangrong wrote:
>>> Changlog:
>>> This are some changes from Marcelo's review:
>>> - drop SPTE_WRITE_PROTECT bit, now, only one bit is needed to do
>>> lockless update.
>>>
>>> - always atomicly update spte if it can be updated out of mmu-lock.
>>>
>>> - flod the judgement of tlb flush into mmu_spte_update(), make the
>>> code easilyer audited.
>>>
>>> Performance result:
>>> - autoest migration test (smp2.Fedora.16.64.migrate.with_autotest.dbench.unix):
>>> before after
>>> smp2.Fedora.16.64.migrate.unix 93 91 +2.1%
>>> smp2.Fedora.16.64.migrate.with_autotest.dbench.unix 218 188 +13.7%
>>>
>>> - the benchmark attached is used to measure the resuming time
>>> after dirty-log
>>> before after
>>> Run 10 times, Avg time: 512466818 ns. 269231261 ns +47.5%
>>
>> Still scary (esp. indirect sptes), but looks pretty good.
>
>
> Hmm, i do not have a better way to solve the ABA problem on indirect spte now. :(
> How about only allow fast page fault to work for direct spte?
>
I'll certainly be more comfortable with that, at least to start with.
--
error compiling committee.c: too many arguments to function
prev parent reply other threads:[~2012-05-24 7:19 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-23 8:51 [PATCH v5 0/9] KVM: fast page fault Xiao Guangrong
2012-05-23 8:51 ` [PATCH v5 1/9] KVM: MMU: return bool in __rmap_write_protect Xiao Guangrong
2012-05-23 8:52 ` [PATCH v5 2/9] KVM: MMU: abstract spte write-protect Xiao Guangrong
2012-05-23 8:53 ` [PATCH v5 3/9] KVM: VMX: export PFEC.P bit on ept Xiao Guangrong
2012-05-23 8:53 ` [PATCH v5 4/9] KVM: MMU: fold tlb flush judgement into mmu_spte_update Xiao Guangrong
2012-05-23 8:55 ` [PATCH v5 5/9] KVM: MMU: introduce SPTE_MMU_WRITEABLE bit Xiao Guangrong
2012-05-23 8:55 ` [PATCH v5 6/9] KVM: MMU: fast path of handling guest page fault Xiao Guangrong
2012-05-23 11:34 ` Avi Kivity
2012-05-24 6:26 ` Xiao Guangrong
2012-05-24 8:25 ` Avi Kivity
2012-05-24 9:03 ` Xiao Guangrong
2012-05-23 8:56 ` [PATCH v5 7/9] KVM: MMU: trace fast " Xiao Guangrong
2012-05-23 8:57 ` [PATCH v5 8/9] KVM: MMU: fix kvm_mmu_pagetable_walk tracepoint Xiao Guangrong
2012-05-23 8:57 ` [PATCH v5 9/9] KVM: MMU: document mmu-lock and fast page fault Xiao Guangrong
2012-05-23 11:37 ` [PATCH v5 0/9] KVM: " Avi Kivity
2012-05-24 6:31 ` Xiao Guangrong
2012-05-24 7:19 ` Avi Kivity [this message]
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