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Re: [Qemu-devel] Better qemu/kvm defaults (was Re: [RFC PATCH 0/4] Gang
From: |
Avi Kivity |
Subject: |
Re: [Qemu-devel] Better qemu/kvm defaults (was Re: [RFC PATCH 0/4] Gang scheduling in CFS) |
Date: |
Thu, 29 Dec 2011 18:13:20 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111115 Thunderbird/8.0 |
On 12/29/2011 06:07 PM, Dor Laor wrote:
> On 12/26/2011 11:05 AM, Avi Kivity wrote:
>> On 12/26/2011 05:14 AM, Nikunj A Dadhania wrote:
>>>>
>>>> btw you can get an additional speedup by enabling x2apic, for
>>>> default_send_IPI_mask_logical().
>>>>
>>> In the host?
>>>
>>
>> In the host, for the guest:
>>
>> qemu -cpu ...,+x2apic
>>
>
> It seems to me that we should improve our default flags.
> So many times users fail to submit the proper huge command-line
> options that we require. Honestly, we can't blame them, there are so
> many flags and so many use cases its just too hard to get it right for
> humans.
>
> I propose a basic idea and folks are welcome to discuss it:
>
> 1. Improve qemu/kvm defaults
> Break the current backward compatibility (but add a --default-
> backward-compat-mode)
This exists, -M pc-1.0.
> and set better values for:
> - rtc slew time
> - cache=none
> - x2apic, maybe enhance qemu64 or move to -cpu host?
We tried this for 1.0, but it caused regressions. Need to try again for
1.1.
> - aio=native|threads (auto-sense?)
> - use virtio devices by default
Can't install non-Linux guests.
> - more?
>
> Different defaults may be picked automatically when TCG|KVM used.
--
error compiling committee.c: too many arguments to function