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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Jason J. Herne" <jjherne@linux.vnet.ibm.com>,
	afaerber@suse.de, amit.shah@redhat.com, dgilbert@redhat.com,
	borntraeger@de.ibm.com, quintela@redhat.com,
	qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v6 1/5] cpu: Provide vcpu throttling interface
Date: Mon, 7 Sep 2015 14:53:07 +0200	[thread overview]
Message-ID: <55ED88B3.7090105@redhat.com> (raw)
In-Reply-To: <1441383989-3377-2-git-send-email-jjherne@linux.vnet.ibm.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 */

  reply	other threads:[~2015-09-07 12:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-04 16:26 [Qemu-devel] [PATCH v6 0/5] migration: Dynamic cpu throttling for auto-converge Jason J. Herne
2015-09-04 16:26 ` [Qemu-devel] [PATCH v6 1/5] cpu: Provide vcpu throttling interface Jason J. Herne
2015-09-07 12:53   ` Paolo Bonzini [this message]
2015-09-07 14:08     ` Andreas Färber
2015-09-04 16:26 ` [Qemu-devel] [PATCH v6 2/5] migration: Parameters for auto-converge cpu throttling Jason J. Herne
2015-09-04 16:26 ` [Qemu-devel] [PATCH v6 3/5] migration: Dynamic cpu throttling for auto-converge Jason J. Herne
2015-09-04 16:26 ` [Qemu-devel] [PATCH v6 4/5] qmp/hmp: Add throttle ratio to query-migrate and info migrate Jason J. Herne
2015-09-04 16:26 ` [Qemu-devel] [PATCH v6 5/5] migration: Disambiguate MAX_THROTTLE Jason J. Herne

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