From: Anthony Liguori <anthony@codemonkey.ws>
To: Avi Kivity <avi@redhat.com>
Cc: Andrew Theurer <habanero@linux.vnet.ibm.com>,
kvm-devel <kvm@vger.kernel.org>
Subject: Re: KVM performance vs. Xen
Date: Thu, 30 Apr 2009 10:08:50 -0500 [thread overview]
Message-ID: <49F9BF02.7090707@codemonkey.ws> (raw)
In-Reply-To: <49F9AD6B.3050300@redhat.com>
Avi Kivity wrote:
> Anthony Liguori wrote:
>>
>>>> 2) cpu_physical_memory_rw due to not using preadv/pwritev?
>>>
>>> I think both virtio-net and virtio-blk use memcpy().
>>
>> With latest linux-2.6, and a development snapshot of glibc,
>> virtio-blk will not use memcpy() anymore but virtio-net still does on
>> the receive path (but not transmit).
>
> There's still the kernel/user copy, so we have two copies on rx, one
> on tx.
That won't show up as cpu_physical_memory_rw. stl_phys/ldl_phys are
suspect though as they degrade to cpu_physical_memory_rw.
Regards,
Anthony Liguori
next prev parent reply other threads:[~2009-04-30 15:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-29 14:41 KVM performance vs. Xen Andrew Theurer
2009-04-29 15:20 ` Nakajima, Jun
2009-04-29 15:33 ` Andrew Theurer
2009-04-30 8:56 ` Avi Kivity
2009-04-30 12:49 ` Andrew Theurer
2009-04-30 13:02 ` Avi Kivity
2009-04-30 13:44 ` Andrew Theurer
2009-04-30 13:47 ` Anthony Liguori
2009-04-30 13:52 ` Avi Kivity
2009-04-30 13:45 ` Anthony Liguori
2009-04-30 13:53 ` Avi Kivity
2009-04-30 15:08 ` Anthony Liguori [this message]
2009-04-30 13:59 ` Avi Kivity
2009-04-30 14:04 ` Andrew Theurer
2009-04-30 15:11 ` Anthony Liguori
2009-04-30 15:19 ` Avi Kivity
2009-04-30 15:59 ` Anthony Liguori
2009-05-01 0:40 ` Andrew Theurer
2009-05-03 16:20 ` Avi Kivity
2009-04-30 15:09 ` Anthony Liguori
2009-04-30 16:41 ` Marcelo Tosatti
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