[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] memory: synchronize dirty bitmap before unmappi
|
From: |
Jan Kiszka |
|
Subject: |
Re: [Qemu-devel] [PATCH] memory: synchronize dirty bitmap before unmapping a range |
|
Date: |
Mon, 01 Aug 2011 09:52:26 +0200 |
|
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2011-08-01 09:34, Jan Kiszka wrote:
> On 2011-07-31 21:47, Avi Kivity wrote:
>> When a range is being unmapped, ask accelerators (e.g. kvm) to synchronize
>> the
>> dirty bitmap to avoid losing information forever.
>>
>> Fixes grub2 screen update.
>
> I does.
>
> But something is still broken. As I reported before, the performance of
> grub2 startup is an order of magnitude slower than with the existing
> code. According to ftrace, we are getting tons of additional
> EPT_MISCONFIG exits over the 0xA0000 segment. But I haven't spot the
> difference yet. The effective slot setup as communicated to kvm looks
> innocent.
I take it back: We obviously once in a while resume the guest with the
vga segment unmapped. And that, of course, ends up doing mmio instead of
plain ram accesses.
Jan
signature.asc
Description: OpenPGP digital signature