From: Tomasz Wroblewski <tomasz.wroblewski@gmail.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel@lists.xenproject.org
Subject: Re: GPU passthrough performance regression in >4GB vms due to XSA-60 changes
Date: Mon, 19 May 2014 13:09:41 +0200 [thread overview]
Message-ID: <5379E675.5010306@gmail.com> (raw)
In-Reply-To: <537A00900200007800013832@mail.emea.novell.com>
On 05/19/2014 01:01 PM, Jan Beulich wrote:
>>>> On 19.05.14 at 12:42, <tomasz.wroblewski@gmail.com> wrote:
>> Actually seems to be like the plausible explanation for the performance
>> issues we see could be that
>>
>> - some region of guest space has been relocated by hvmloader out to
>> 64bit memory to enlarge pci mmio hole (which stays in 32bit space)
>> - BUT the caching on that relocated region is UC since at the time of
>> the relocation MTRR was disabled and that caused the EPT entry to get UC
>> type.
> But this would be easily seen from 'D' debug key output - did you
> check this is what is the case?
Yes I've checked that, though I used some homebrew EPT dumping code
instead. Mentioned it a bit earlier, in the original post as well as
http://lists.xen.org/archives/html/xen-devel/2014-05/msg01965.html. I
just incorrectly thought that it's the BAR being relocated which
introduced some confusion..
> Jan
>
next prev parent reply other threads:[~2014-05-19 11:09 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-15 9:11 GPU passthrough performance regression in >4GB vms due to XSA-60 changes Tomasz Wroblewski
2014-05-15 12:32 ` Jan Beulich
2014-05-15 12:10 ` Tomasz Wroblewski
2014-05-15 13:23 ` Jan Beulich
2014-05-15 13:39 ` Tomasz Wroblewski
2014-05-15 14:34 ` Tomasz Wroblewski
2014-05-15 14:56 ` Tomasz Wroblewski
2014-05-15 16:07 ` Jan Beulich
2014-05-15 15:39 ` Tomasz Wroblewski
2014-05-16 6:33 ` Jan Beulich
2014-05-16 11:18 ` Tomasz Wroblewski
2014-05-16 11:38 ` Jan Beulich
2014-05-16 14:36 ` Jan Beulich
2014-05-19 10:29 ` Tomasz Wroblewski
2014-05-19 10:38 ` Jan Beulich
2014-05-19 10:47 ` Tomasz Wroblewski
2014-05-19 11:07 ` Jan Beulich
2014-05-19 11:32 ` Tomasz Wroblewski
2014-05-19 12:06 ` Jan Beulich
2014-05-19 12:17 ` Tomasz Wroblewski
2014-05-19 12:44 ` Jan Beulich
2014-05-19 14:20 ` Tomasz Wroblewski
2014-05-19 15:24 ` Jan Beulich
2014-05-19 15:48 ` Tomasz Wroblewski
2014-05-19 17:36 ` Tim Deegan
2014-05-20 6:31 ` Jan Beulich
2014-05-19 10:42 ` Tomasz Wroblewski
2014-05-19 11:01 ` Jan Beulich
2014-05-19 11:09 ` Tomasz Wroblewski [this message]
2014-05-19 11:19 ` Jan Beulich
2014-05-15 16:01 ` Jan Beulich
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