More -ve slack in in-reg path

[prithivikumars]

Hi,


I am having more -ve slack in i/p-reg path. Is there is any command to optimize only i/p-reg path in magma. Is there any other way to get +ve slack.

Prithivi.

 

[praneshcn]

hi,

have u tried normal optimization techniques on the particular net like buffering , sizing etc. if so wat change did u get?

rgds

 

[prithivikumars]

Hi,

I am having violations in 3000 paths. How to do individually for all the paths?


Prithivi.

 

[praneshcn]

hi,
at wat stage r u getting the violations?

 

[iwpia50s]

Magma has the option to normalize IO paths to zero, try setting that option. Also, you probably need to check you set_input_delay in your timing constraints...sounds like they are not correct.

 

[prithivikumars]

Hi,

I am getting violation in Pre-CTS stage.

Prithivi.

 

[praneshcn]

"Magma has the option to normalize IO paths to zero, try setting that option"

Hi iwpia50s,
Do you mean the command run timing adjust io $m -slack_target 0 or any other command.


thnxz.

Added after 5 minutes:

hi prithvi,

For pre cts stage timing optimization try

* run gate size $m -effort high
* run place timing $m
* run place detail $m

Also u can try fix opt global $m $l.

please verify whether the design is over constrained or not.

 

[sam536]

I am not sure about how magma works about this part.

usually, when input to Register paths are having violations, with Synopsys tools, we will group them in separte Group as IN_REG path group and applay some critical range value to work better optimization techniques. The optimization tools work on per path per clock group basis. If u can divide these violation with path groups into separate and set critical parameters to optimize, the negative slack may come down.

Check your input delay value. check the input delay applied with which clock and end point is with which clock?. The edges some time doesnt match and will be very less time for optimization..

Regards,
Sam

 

[praneshcn]

hi prithvi

Have u solved this problem. if so hw did u go tat?


thnx