qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH v4 1/5] cpu: Provide vcpu throttling interface


From: Jason J. Herne
Subject: Re: [Qemu-devel] [PATCH v4 1/5] cpu: Provide vcpu throttling interface
Date: Tue, 01 Sep 2015 10:43:14 -0400
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0

On 08/01/2015 05:40 AM, Paolo Bonzini wrote:


On 31/07/2015 20:11, Jason J. Herne wrote:


Doh! Yep :). This problem is an artifact of moving the timer_mod from
cpu_throttle_thread into cpu_throttle_timer_tick. I'll have to go back
to the review comments and look at why that was done.

So, we made that change in v3 to eliminate the per cpu timer. With a per
cpu timer we avoid this problem and we no longer need to worry about
a throttle_thread_scheduled, and timers stacking. Paolo, you had originally
argued in favor of this change. With what we know now, do you still think
having only a single timer is best? Or should I switch back to a timer per
cpu? With a timer per cpu we can simply reset the timer immediately after
the sleep.

It's okay to have a single timer, only the formulas have to be
corrected: either you remove the pct/(1-pct) from the callback or you
add a /(1-pct) to the timer_mod.

Paolo

Paolo,

You are correct here. I've adjusted the timer formula and tested. Everything seems to be playing nicely now. Sorry it took me a month to get to this. I got pulled into some critical work and improved auto-converge took a back seat. I know it is a pain to go back to something you have not seen in a month so I appreciate any attention this gets :). A new patch set will be inbound shortly...

--
-- Jason J. Herne (address@hidden)




reply via email to

[Prev in Thread] Current Thread [Next in Thread]