cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
Highlighted
Visitor
Visitor
4,942 Views
Registered: ‎05-04-2016

How to interpret "paths in yellow" in the timing report - are they warnings

Jump to solution

Good day,

 

I know that in the "timing summary report" if there is a path that is failing to meet timing closure vivado will show it with an red arrow symbol on the left of the message.

Read arrow.JPG

 

However, when my design meets timing an successfully completes implementation I have seen paths with yellow arrows:

 

Yellow Arrows.JPG

I assume these may be sort of warnings.  When should I be concerned about them?


Thanks

 

JCV65

 

 

0 Kudos
1 Solution

Accepted Solutions
Highlighted
Guide
Guide
8,752 Views
Registered: ‎01-23-2009

(To be honest, I never noticed...)

 

Yellow just means not red - I don't think they ever turn green...

 

No, you don't have to worry about them - if the path meets timing, then it is fine.

 

Avrum

View solution in original post

Tags (1)
0 Kudos
8 Replies
Highlighted
Guide
Guide
8,753 Views
Registered: ‎01-23-2009

(To be honest, I never noticed...)

 

Yellow just means not red - I don't think they ever turn green...

 

No, you don't have to worry about them - if the path meets timing, then it is fine.

 

Avrum

View solution in original post

Tags (1)
0 Kudos
Highlighted
Visitor
Visitor
4,926 Views
Registered: ‎05-04-2016

Thanks!...  This may be good feedback to Vivado GUI designers...

0 Kudos
Highlighted
Visitor
Visitor
4,921 Views
Registered: ‎05-04-2016

I mean, I would not expect the paths to turn green... However, if there is nothing to be worried about them Vivado designers should consider not showing any good paths, or show all of them.

0 Kudos
Highlighted
Mentor
Mentor
4,918 Views
Registered: ‎06-09-2011

As @avrumw mentioned, you do not need to do anything and it means that Your specified timing is OK!. 

However, these are an indication for paths or clocks you have specified in your constraint file!.

If you want to make sure that nothing else is wrong with your design and it would definitely work without any problem you are better take a look at the Project Summery as well. There you can find the project implementation confidence Level!. it shows if you have not specified your IO specifications or others!. Below picture shows the meaning of every level:

Confidence Level.jpg

 

Hossein

Thanks,
Hossein
Highlighted
Visitor
Visitor
4,915 Views
Registered: ‎05-04-2016

Good to know!  Thanks!

0 Kudos
Highlighted
Guide
Guide
4,914 Views
Registered: ‎01-23-2009

The number of paths shown is an option to the report_timing command (and available in the GUI from the Options window of the Report Timing window). By default the number of paths shown per group is 10 - so you see 10 regardless of how many pass an how many fail.

 

The report_timing command is VERY flexible - probably having more options than any other command in Vivado. If, for example, you only want to see failing paths, then you can use the Tcl option -slack_less_than 0 option (and an equivalent is given in the Options page) - now you will only see failing paths.

 

If you want to show all paths (and I don't recommend it), there are options for that as well - also controlled in the Options pane. -max_paths 100000000 -nworst 100000000 will show the one hundred million worst paths! However (on a large design) this command may take almost forever to complete, and would generate an immense report  - remember, the number of paths in a design can grow quite quickly - O(N^2).

 

Avrum

Tags (1)
Highlighted
Guide
Guide
4,912 Views
Registered: ‎01-23-2009

There you can find the project implementation confidence Level!

 

Careful - the confidence level here is the confidence level of the power analysis results - not the design in general.

 

If you want to make sure your constraints are good, use the check_timing command (or the Check Timing option in the GUI). This is also included by default in the Report Timing Summary.

 

Avrum

Tags (1)
Highlighted
Mentor
Mentor
4,909 Views
Registered: ‎06-09-2011

Thank you so much @avrumw.

As always accurate and great!.

Thanks,
Hossein
0 Kudos