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Re: [Qemu-devel] Speed menu for GTK interfaace
From: |
Programmingkid |
Subject: |
Re: [Qemu-devel] Speed menu for GTK interfaace |
Date: |
Wed, 4 Jan 2017 10:43:46 -0500 |
On Jan 4, 2017, at 3:37 AM, Gerd Hoffmann wrote:
> Hi,
>
>> It is quite simple, there would be a 100% to a 1% menu item. It would look
>> like
>> this:
>>
>> Speed
>> -------
>> 100%
>> 90%
>> 80%
>> 70%
>> 60%
>> 50%
>> 40%
>> 30%
>> 20%
>> 10%
>> 1%
>>
>>
>> Each menu item would call cpu_throttle_set(). The value sent to this
>> function would
>> be determined like this:
>> speed = -1 * menu_number + 100;
>
> ok, that is the info I was looking for.
>
>> speed would be sent to the cpu_throttle_set() function. This function would
>> reduce
>> the CPU usage of QEMU on the host.
>>
>> Why would someone want to slow down QEMU?
>> - The user is using a laptop and don't want it to heat up.
>
> Sort-of makes sense, to keep the laptop quiet.
>
>> - The user wants to slow down a video game that is a little too challenging.
>
> Sure this would work? Throttling isn't a smooth slowdown, the cpu
> continues to run at full speed and is forced to pause now and then.
>
>> - The user wants to save energy.
>
> Pointless. Laptop may run longer, but your job needs more time to
> complete too. And constant vcpu start/stop isn't good to save power,
> the cpus can't enter deep sleep states then because of the frequent
> wakeups.
>
>> - The user wants to conduct some kind of stress test on a program and see how
>> it handles under low cpu resources.
>
> Makes sense too.
>
> We already have "pause" in gtk, adding a "throttle" item next to it
> looks reasonable to me. I don't think it is that useful to have 10%
> steps in there, you probably never throttle 10% in practice. It's
> probably more useful to have something like "throttle -> off / 50% /
> 90% / 95% / 99%".
Actually the 10% one is the one I use the most. I use it when I have to
test code in OpenBIOS. I wouldn't mind adding a 95% menu item.
- [Qemu-devel] Speed menu for GTK interfaace, Programmingkid, 2017/01/01
- Re: [Qemu-devel] Speed menu for GTK interfaace, Gerd Hoffmann, 2017/01/03
- Re: [Qemu-devel] Speed menu for GTK interfaace, Programmingkid, 2017/01/03
- Re: [Qemu-devel] Speed menu for GTK interfaace, Gerd Hoffmann, 2017/01/04
- Re: [Qemu-devel] Speed menu for GTK interfaace,
Programmingkid <=
- Re: [Qemu-devel] Speed menu for GTK interfaace, Daniel P. Berrange, 2017/01/04
- Re: [Qemu-devel] Speed menu for GTK interfaace, Programmingkid, 2017/01/04
- Re: [Qemu-devel] Speed menu for GTK interfaace, Daniel P. Berrange, 2017/01/04
- Re: [Qemu-devel] Speed menu for GTK interfaace, Programmingkid, 2017/01/04
- Re: [Qemu-devel] Speed menu for GTK interfaace, Gerd Hoffmann, 2017/01/04