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Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unex
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions |
Date: |
Mon, 06 Mar 2017 13:08:56 +0000 |
User-agent: |
mu4e 0.9.19; emacs 25.2.8 |
Frédéric Konrad <address@hidden> writes:
> Hi Jim,
>
> I think Alex and Paolo worked on an mttcg/icount issue.
> Not sure if its related or not.
If you are running a tree post-MTTCG merge you will need to add Paolo's
patches:
Subject: [PATCH 0/6] tcg: fix icount super slowdown
Date: Fri, 3 Mar 2017 14:11:08 +0100
Message-Id: <address@hidden>
>
> Fred
>
> On 03/03/2017 08:38 PM, Nutaro, James J. wrote:
>> My original problem seems to stem from something that changed in the way
>> that device emulation and instruction execution interact (I'm guessing). To
>> reproduce the issue, I started a linux image with
>>
>> qemu-system-i386 -rtc clock=vm -monitor none -icount 1,sleep=off jack.img
>>
>> After booting, I run
>>
>> ping localhost
>>
>> The first round trip time reports look reasonable, being in the millisecond
>> to sub-millisecond range. These occur while the emulator is running slower
>> than real time.
>>
>> After a bit, the emulator speeds up (skipping over idle periods during I/O?)
>> and the round trip times jump to hundreds of milliseconds, which I had not
>> expected.
>>
>> If you want to try this experiment yourself, you can get the disk image that
>> I used from here:
>>
>> http://www.ornl.gov/~1qn/qemu-images/jack.img
>>
>>
>> Jim
>>
--
Alex Bennée
- Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions, Nutaro, James J., 2017/03/03
- Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions, Frédéric Konrad, 2017/03/03
- Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions,
Alex Bennée <=
- Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions, Pavel Dovgalyuk, 2017/03/07
- Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions, Alex Bennée, 2017/03/13
- Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions, Pavel Dovgalyuk, 2017/03/14
- Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions, Paolo Bonzini, 2017/03/14
- Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions, Pavel Dovgalyuk, 2017/03/14
- Re: [Qemu-devel] -rtc clock=vm with -icount 1, sleep=off introduces unexpected delays in device interactions, Paolo Bonzini, 2017/03/14