From: Eric Blake <eblake@redhat.com>
To: Chen Hanxiao <chen_han_xiao@126.com>
Cc: qemu-devel@nongnu.org, Michael Roth <mdroth@linux.vnet.ibm.com>
Subject: Re: [Qemu-devel] [PATCH] qga: add mountpoint usage to GuestFilesystemInfo
Date: Wed, 30 May 2018 08:05:34 -0500 [thread overview]
Message-ID: <9335469d-ee0f-e6ac-7570-0b5ccab1ca57@redhat.com> (raw)
In-Reply-To: <5e690898.591a.163afd447ec.Coremail.chen_han_xiao@126.com>
On 05/30/2018 01:55 AM, Chen Hanxiao wrote:
>>> + usage = u100 / nonroot_total + (u100 % nonroot_total != 0);
>>
>> Why integral instead of floating point?
>
> I followed the style of df from coreutils.
> As the percentage already multiplied by 100,
> I think it has enough precision.
You're making an arbitrary policy decision. Give the client a floating
point, and they can still truncate to print out a 2-digit percentage.
But give them a percentage, and for a 2T disk image, they are forced to
guess whether they are 20G high or low on usage, which starts to take a
non-trivial amount of time to copy that much data. In other words, I
think an int is wrong for being too imprecise.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
prev parent reply other threads:[~2018-05-30 13:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-30 3:01 [Qemu-devel] [PATCH] qga: add mountpoint usage to GuestFilesystemInfo Chen Hanxiao
2018-05-30 3:19 ` Eric Blake
2018-05-30 3:20 ` Eric Blake
2018-05-30 6:55 ` Chen Hanxiao
2018-05-30 13:05 ` Eric Blake [this message]
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