Re: [Qemu-devel] [RFC v2 09/11] tcg: add kick timer for single-threaded vCPU emulation

From: Sergey Fedorov <serge.fdrv@gmail.com>
To: "Alex Bennée" <alex.bennee@linaro.org>,
	mttcg@listserver.greensocs.com, fred.konrad@greensocs.com,
	a.rigo@virtualopensystems.com, cota@braap.org
Cc: qemu-devel@nongnu.org, mark.burton@greensocs.com,
	pbonzini@redhat.com, jan.kiszka@siemens.com, rth@twiddle.net,
	peter.maydell@linaro.org, claudio.fontana@huawei.com,
	Peter Crosthwaite <crosthwaite.peter@gmail.com>
Subject: Re: [Qemu-devel] [RFC v2 09/11] tcg: add kick timer for single-threaded vCPU emulation
Date: Tue, 12 Apr 2016 00:39:55 +0300	[thread overview]
Message-ID: <570C19AB.5020106@gmail.com> (raw)
In-Reply-To: <1459870344-16773-10-git-send-email-alex.bennee@linaro.org>

On 05/04/16 18:32, Alex Bennée wrote:
> +static void kick_tcg_thread(void *opaque)
> +{
> +    QEMUTimer *self = *(QEMUTimer **) opaque;
> +    timer_mod(self,
> +              qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
> +              NANOSECONDS_PER_SECOND / 10);
> +    qemu_cpu_kick_no_halt();
> +}
>  

It would be nice to have some definition (e.g. macro) of TCG thread kick
period.

(snip)

> @@ -1179,6 +1198,14 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
>          }
>      }
>  
> +    /* Set to kick if we have to do more than one vCPU */
> +    if (CPU_NEXT(first_cpu)) {
> +        kick_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,  kick_tcg_thread, &kick_timer);
> +        timer_mod(kick_timer,
> +                  qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
> +                  NANOSECONDS_PER_SECOND / 10);
> +    }
> +    

I think cpu_ticks_init() could be more natural place to put this
initialization in.

Kind regards,
Sergey