Re: [PATCH] kvm: add halt_poll_ns module parameter

From: Xiao Guangrong
Date: Mon Feb 09 2015 - 05:13:16 EST

On 02/09/2015 05:06 PM, Paolo Bonzini wrote:

On 09/02/2015 09:22, Xiao Guangrong wrote:

On 02/06/2015 08:48 PM, Paolo Bonzini wrote:

+unsigned int halt_poll_ns = 0;
+module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR);

Can we make this parameter be changeable? So that we can tune it
on the fly.

It is changeable (S_IWUSR).

Oh... Yes, sorry for my careless.

finish_wait(&vcpu->wq, &wait);
+ cur = ktime_get();

We can move this into the tracepoint to avoid the workload if the
tracepoint is not enabled.

You have a point. I didn't do it because I expect that halt_poll_ns
will be always enabled as soon as it auto-tunes, and in that case you'll
always have to do the ktime_get() for autotuning purposes.

Great, look forward to your future patches. ;)

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