Re: [Qemu-devel] [PATCH v6 1/5] cpu: Provide vcpu throttling interface

[Paolo Bonzini <pbonzini@redhat.com>]

On 04/09/2015 18:26, Jason J. Herne wrote:
> +    pct = (double)cpu_throttle_get_percentage()/100;
> +    throttle_ratio = pct / (1 - pct);
> +    sleeptime_ms = (long)(throttle_ratio * CPU_THROTTLE_TIMESLICE);

This is going to be pretty imprecise, since there are only 11 possible
values of sleeptime_ms.  Can you switch the timer and
CPU_THROTTLE_TIMESLICE to nanosecond precision instead?

It's okay to provide this as a patch 6/5, and the maintainer will squash
it into this patch.  Alternatively this can be sent as v7, as you prefer.

Paolo

> +
> +    qemu_mutex_unlock_iothread();
> +    atomic_set(&cpu->throttle_thread_scheduled, 0);
> +    g_usleep(sleeptime_ms * 1000); /* Convert ms to us for usleep call */