Is resource logic utilization report correct? more than 100% can still fit into FPGA?

[Altera_Forum]

Hi, 

 I'm using SocKit doing some tests with opencl. After the first stage compile, the resource usage report says the logic utilization is 112%. I just want to try if this can fit into sockit since I don't want to change the kernel so much, and after the second stage, it just fit. The kernel runs correctly also on FPGA.   Then I tried to modify the code and the report says using 127%, 139%, and both of them can pass the second stage and kernel runs correctly.  But the 159% failed.  SO the resource usage report is not so accurate, right? This is a bug or should i just try it instead of really trust this report?  Thanks  Shaodong

[Altera_Forum]

--- Quote Start ---  Hi,  I'm using SocKit doing some tests with opencl. After the first stage compile, the resource usage report says the logic utilization is 112%. I just want to try if this can fit into sockit since I don't want to change the kernel so much, and after the second stage, it just fit. The kernel runs correctly also on FPGA.   Then I tried to modify the code and the report says using 127%, 139%, and both of them can pass the second stage and kernel runs correctly.  But the 159% failed.  SO the resource usage report is not so accurate, right? This is a bug or should i just try it instead of really trust this report?  Thanks  Shaodong  --- Quote End ---    The resource usage report is a conservative approximation, not absolute. You can use it to understand the impact of your code changes on the resource usage, e.g if the estimated usage goes up, you can expect that the real usage will also go up.  There are plans to make the report more accurate in the future. However, there will always be some mismatches since it is hard to compute the actual resource usage before synthesizing the circuit.