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Re: [Qemu-devel] Speed menu for GTK interfaace
From: |
Gerd Hoffmann |
Subject: |
Re: [Qemu-devel] Speed menu for GTK interfaace |
Date: |
Wed, 04 Jan 2017 09:37:39 +0100 |
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%".
cheers,
Gerd
- [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 <=
- 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, 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