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

Thu Nov 14 07:21:03 UTC 2013

On Nov 14, 2013, at 00:09 , Einav Cohen <ecohen at redhat.com> wrote:

>> ... but we may have to see how this looks when multiple sparklines 
>> reside in columns next to each other.
>> ...
>> ...
>> Is this going to fit in a row of a table? Or are we talking of a 
>> more detailed view?
>> ...
> 
> a concern on which I happened to briefly discuss with Eldan / Malini 
> and actually somewhat raised here earlier in the thread (see above): 
> Since we are adding another information "dimension" (time), we are 
> actually going to display a lot more information to the user within the 
> CPU/MEM/NET columns, and there is a chance that the view will become 
> too overloaded/confusing, and we will end up with a view that is less 
> clear than the current one.

Well, for that we IMHO have much bigger issue already with the fact we do not hide/show columns, and many of them do not really provide much value in all use cases. If you look at the mockup and the screenshots from users I've seen  - e.g. the Display column(don't care), the Cluster (not wide enough, repetition of the same info on each line), Host(repetition of domain parts of FQDN) makes it overloaded already. 
Since statistics do provide some value and it keeps changing based on load it IMHO looks ok
...maybe just a global setting to disable this if it gets annoying? It's a small feature and it's trivial to add such a setting.

> 
> Just so we will have a general idea of how it will look like eventually, 
> so we will be able to do a slightly more educated decision, I am attaching 
> a mock-up of how it looks now compared to how it may look once this 
> feature is implemented. 
> 
> * In my mock-up, I followed Malini's guideline from earlier in the thread:
> """
> One color with a dot to indicate the most recent or most relevant data 
> and display its value next to the sparkline
> """

Thanks for the mock up, I think it looks great. Perhaps I'd consider lines instead of dots (to see the base 0, currently the line is somehow "in the air" and since the height is limited it may be difficult to distinguissh 20% from 0%), provided they are in some light color it may look ok

> 
> * keep in mind that the view is dynamic and keeps updating once it 
> receives new statistics from the backend. 
> 
> Thoughts?
> 
> 
> ----- Original Message -----
>> From: "Malini Rao" <mrao at redhat.com>
>> To: "Tomas Jelinek" <tjelinek at redhat.com>
>> Cc: "Einav Cohen" <ecohen at redhat.com>, "engine-devel" <engine-devel at ovirt.org>, "Eldan Hildesheim"
>> <ehildesh at redhat.com>, "info" <info at eldanet.com>, "Martin Polednik" <mpoledni at redhat.com>
>> Sent: Wednesday, November 6, 2013 10:24:56 AM
>> Subject: Re: [Engine-devel] [UX] how to design a bar/line chart?
>> 
>> 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
>>>>> 
>>>>> 
>>>>> 
>>>> 
>>> 
> <trendline-mockup.png>