[Engine-devel] [UX] how to design a bar/line chart?

Wed Nov 6 15:24:56 UTC 2013

Hey all, 

Comments inline-

----- Original Message -----
> From: "Tomas Jelinek" <tjelinek at redhat.com>
> To: "Einav Cohen" <ecohen at redhat.com>
> Cc: "engine-devel" <engine-devel at ovirt.org>, "Eldan Hildesheim" <ehildesh at redhat.com>, "info" <info at eldanet.com>,
> "Malini Rao" <mrao at redhat.com>, "Martin Polednik" <mpoledni at redhat.com>
> Sent: Wednesday, November 6, 2013 9:58:03 AM
> Subject: Re: [Engine-devel] [UX] how to design a bar/line chart?
> 
> Hi Einav,
> 
> ----- Original Message -----
> > From: "Einav Cohen" <ecohen at redhat.com>
> > To: "Tomas Jelinek" <tjelinek at redhat.com>
> > Cc: "engine-devel" <engine-devel at ovirt.org>, "Eldan Hildesheim"
> > <ehildesh at redhat.com>, "info" <info at eldanet.com>,
> > "Malini Rao" <mrao at redhat.com>
> > Sent: Wednesday, November 6, 2013 3:26:15 PM
> > Subject: Re: [Engine-devel] [UX] how to design a bar/line chart?
> > 
> > Hi Tomas,
> > 
> > Like Itamar, I think that a line chart is a better idea, and that a
> > chart per monitored fact (rather than a combined chart) is better.
> 
> OK

Based on the original request in the bug, it seems like Itamar is looking for a trend rather than just one data point. I think we are thinking along the correct lines here with a line graph but I think more specifically, we should consider sparklines - http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0001OR. Agree that we should have one sparkline per fact but we may have to see how this looks when multiple sparklines reside in columns next to each other. See example of a grid where there are 2 sparklines next to each other - http://www.panopticon.com/Tables-Grids

> 
> > 
> > > > the statistics readable enough. Maybe if you hover the chart it could
> > > > pop
> > > > up a bigger version of the chart? Or not needed?
> > 
> > this is a nice-to-have, I think, definitely not needed.
> 
> OK

Agree. As shown in the glucose example in the Tufte link I posted above, maybe all we need is to indicate the acceptable range with a band and if the last point is in the range or outside, it will be clear to the user if they should pay attention to it. 

> 
> > 
> > > > - Would it be enough to have it in one color? Or should it be something
> > > > like "the bigger the utilization the more red"?
> > 
> > question is what will happen when there are a lot of "jumps": let's say
> > that the graph changes from 0% to 100% to 0% to 100% and so on... what
> > will be painted red? the entire line, but only in the periods that it
> > jumps to 100%? only the parts of line that are in 100%?
> > maybe a single color is enough.
> 
> OK
> 

One color with a dot to indicate the most recent or most relevant data and display its value next to the sparkline

> > 
> > I have another concern about this feature: currently, the GUI's most
> > frequent
> > refresh rate available is 5 seconds, which means that the line will
> > "change"
> > only every 5 seconds, which would be more noticeably slow when displayed in
> > a form of a line chart (not even talking about lower frequencies).
> > Moreover, I am not sure at what rate the VM statistics are pulled from
> > VDSM,
> > but if it is 10 seconds or 15 seconds, it means that the line in the GUI
> > will
> > be "flat" for every 2 reads / 3 reads, which is not so good, I think.
> > 
> > any thoughts around that?
> 
> Good point! AFAIK the VDSM is polled each 3 seconds for basic info (e.g. the
> resource
> usage not included) and than every 5th poll (e.g. every 15 seconds) for full
> data
> (with resource usage not included). This would indeed make the graph pretty
> useless.
> 
> Michal proposed to do some averages on the VDSM site from more frequent
> sampling and
> send this average back to engine when polled - so we would display an average
> after each poll (15s).
> 
> I wonder if something like this is not already used on other places:
> @Martin, do you know about something like this?

Why does the change in the line need to seem palpable every few seconds? I think the base requirement of how accurate the data is when a user looks at a grid has not changed.. just the data visualization. Right? So , if the refresh rate is not a problem today, why is it a problem now? Am I missing something?

> 
> 
> > 
> > ----- Original Message -----
> > > From: "Itamar Heim" <iheim at redhat.com>
> > > To: "Tomas Jelinek" <tjelinek at redhat.com>, "engine-devel"
> > > <engine-devel at ovirt.org>
> > > Sent: Tuesday, November 5, 2013 10:10:34 AM
> > > Subject: Re: [Engine-devel] [UX] how to design a bar/line chart?
> > > 
> > > On 11/05/2013 11:50 AM, Tomas Jelinek wrote:
> > > > Hi all,
> > > >
> > > > There is a feature request [1] which aims to replace the resource
> > > > utilization graphs (for example the cpu utilization from vm tab) by
> > > > some
> > > > which shows not only
> > > > the actual percentage which is not so useful by some monitor graph.
> > > >
> > > > I have the following concerns:
> > > > - I can think of a bar chart or a line chart and not sure what would be
> > > > better.
> > > > - Not sure if replacing the current chart with a bar/line chart would
> > > > make
> > > > the statistics readable enough. Maybe if you hover the chart it could
> > > > pop
> > > > up a bigger version of the chart? Or not needed?
> > > > - Would it be enough to have it in one color? Or should it be something
> > > > like "the bigger the utilization the more red"?
> > > >
> > > > Please advise from the UX perspective. As soon as the final design will
> > > > be
> > > > a bit more clear I will provide a feature page.
> > > >
> > > > Thank you,
> > > > Tomas
> > > >
> > > > [1]: https://bugzilla.redhat.com/show_bug.cgi?id=803251
> > > > _______________________________________________
> > > > Engine-devel mailing list
> > > > Engine-devel at ovirt.org
> > > > http://lists.ovirt.org/mailman/listinfo/engine-devel
> > > >
> > > 
> > > a moving trend graph (just like fedora's system monitor for
> > > cpu/ram/network) is what i have in mind. so a line chart.
> > > you could have a single chart with different lines for cpu/ram/network,
> > > or what seems to be more common, a chart per monitored fact
> > > _______________________________________________
> > > Engine-devel mailing list
> > > Engine-devel at ovirt.org
> > > http://lists.ovirt.org/mailman/listinfo/engine-devel
> > > 
> > > 
> > > 
> > 
> 