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linzhongduo
Explorer
Explorer
1,363 Views
Registered: ‎10-09-2014

Longer implementation time in 2017.4 and 2018.1

Hi,

 

I have two slightly different designs targeting KU115 device. In Vivado 2017.2, the implementation time is about 4 hours. However, when I used 2017.4 and 2018.1 with same option (PostRoutePhyOpt), it is taking me about 5 hours. I tried with three runs per version, and the one hour difference is quite clear to me. I have excluded the only runs in 2017.4 and 2018.1 in which PostRoutePhyOpt actually does something. All of the runs meet timing eventually. Is this expected?

 

Thanks,

Jimmy

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4 Replies
jmcclusk
Mentor
Mentor
1,346 Views
Registered: ‎02-24-2014

First, thank you for running these benchmarks!

 

Secondly, these results are not surprising, given that new (and more complex) algorithms are put into Vivado to help close timing.  If it's taking longer, then I can only conclude that the Vivado is able to close timing on more difficult designs, given the increased routing time.   I kinda wish that Xilinx would do some research into GPU acceleration for place & route.

 

I just downloaded 2018.1 this morning, and I will be testing it tonight and tomorrow.  Now it's time to read the release notes!

Don't forget to close a thread when possible by accepting a post as a solution.
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linzhongduo
Explorer
Explorer
1,342 Views
Registered: ‎10-09-2014

Hi @jmcclusk,

Thanks for the reply. Unfortunately I cannot speak for the improved ability to close timing as I don't have a design that doesn't meet timing. However, one more hour or 25% longer run time is quite significant to me. The release note is showing an route option of ultrathread that can improve timing, but it doesn't seem available in project mode. GPU may be a big one, but I think even allowing more than 8 threads will be nice if the algorithm is that scalable.

Jimmy
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peadard
Moderator
Moderator
1,275 Views
Registered: ‎02-07-2008

@linzhongduo, agree, 25% is a significant increase. If I were to send you a PM, would you be willing to submit the 2017.2 design so I can run some local tests with it?

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linzhongduo
Explorer
Explorer
1,245 Views
Registered: ‎10-09-2014

Hi @peadard,

 

Sure. I can send you a linked design check point. 

 

Thanks,

Jimmy

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