From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:45528)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1XdeNs-00076u-UT
	for qemu-devel@nongnu.org; Mon, 13 Oct 2014 08:06:01 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1XdeNg-0006Ks-Lp
	for qemu-devel@nongnu.org; Mon, 13 Oct 2014 08:05:52 -0400
Received: from mail-wi0-x22d.google.com ([2a00:1450:400c:c05::22d]:49542)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1XdeNg-0006Kb-F2
	for qemu-devel@nongnu.org; Mon, 13 Oct 2014 08:05:40 -0400
Received: by mail-wi0-f173.google.com with SMTP id fb4so7219225wid.0
	for <qemu-devel@nongnu.org>; Mon, 13 Oct 2014 05:05:39 -0700 (PDT)
Sender: Paolo Bonzini <paolo.bonzini@gmail.com>
Message-ID: <543BC00E.2060907@redhat.com>
Date: Mon, 13 Oct 2014 14:05:34 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
MIME-Version: 1.0
References: <1411572065-18072-1-git-send-email-benoit.canet@nodalink.com>
	<1411572065-18072-4-git-send-email-benoit.canet@nodalink.com>
In-Reply-To: <1411572065-18072-4-git-send-email-benoit.canet@nodalink.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Subject: Re: [Qemu-devel] [PATCH v3 3/3] util: Infrastructure for computing
	recent averages
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: =?UTF-8?B?QmVub8OudCBDYW5ldA==?= <benoit.canet@nodalink.com>, qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, armbru@redhat.com

Il 24/09/2014 17:21, Benoît Canet ha scritto:
> The module takes care of computing minimal and maximal
> values over the time slice duration.

The code looks good, just two comments:

> +/* Get the average value
> + *
> + * @ta:  the timed average structure used
> + * @ret: the average value
> + */
> +uint64_t timed_average_avg(TimedAverage *ta)
> +{
> +    Window *w;
> +    check_expirations(ta);
> +
> +    w = current_window(ta);
> +
> +    if (w->count) {
> +        return w->sum / w->count;

First, do we want this to return double?

Second, this will return the min/max/avg in an unknown amount of time
between period/2 and period---on average period*3/4, e.g. 0.75 seconds
for a period equal to one second.

Would it make sense to tweak the TimedAverage period to be higher, e.g.
1.33 seconds/80 seconds/80 minutes, so that the _average_ period is 1
second/1 minute/1 hour?

This only applies to how the code is used, not to TimedAverage itself;
hence, feel free to post the patch with Reviewed-by once
timed_average_avg's return type is changed to a double.

Paolo

> +    }
> +
> +    return 0;
> +}
> +
> +/* Get the maximum value
> + *
> + * @ta:  the timed average structure used
> + * @ret: the maximal value
> + */
> +uint64_t timed_average_max(TimedAverage *ta)
> +{
> +    check_expirations(ta);
> +    return current_window(ta)->max;
> +}
>