Hello all, I have finally gotten some code I have been working on to compile, specifically after installing the April update to the OpenCL compiler. However, the Compile has been going for almost a week now, is there something wrong or is a long compile time possible for complex code? Sincerely, Aaron S.

When exactly, which task (analyse, fitter...) does it spend very much time ? You have also Quartus Advisor in menu Quartus > Tools > .... > compile time advisor where you get advices and where you can "fix" settings.

It is during the OpenCL compile that I have the problem, I am only running aoc -c -v etc. Sincerely, Aaron S.

Double check your kernel to make sure there are not any coding structures that could cause the compiler problems (like recursion). If you have any of the performance attributes or the unroll pragma defined in your kernel try scaling those back. The only time I have run into the issue you are seeing is when had an incredibly deep dependency tree in my kernel that became much worst when I unrolled a long loop.

Thank you for your reply, I guess I have 2 questions. 1) Is the compile in an infinite loop? 2) Without unrolling all of the loops the logic utilization was above 100% so is there a way to balance the two issues, loop unrolls and logic utilization? Sincerely, Aaron S.

The compiler will probably finish eventually but I always end up killing it because if it takes that long to generate the logic then I Quartus will take a while to synthesize the logic. I don't really have an answer for# 2 because it's very kernel specific and each way you tackle the problem is different. If you can share kernel through a service request or FAE I'm sure Altera can take a look and make suggestions. One thing to look into is whether your kernel is sequential in nature. For example the vector_add kernel posted on the design examples page on www.altera.com (http://www.altera.com) could easily be written as a task kernel like this: __attribute ((task)) __kernel void vectorAdd(__global const float * restrict x, __global const float * restrict y, __global float * restrict z, int N) { // iterate over elements of the arrays instead of indexing using work-item ID for(int index = 0; index < N; index++) { // add the vector elements z = x + y; } } Since a task kernel only operates over a single work-item often the hardware footprint is much smaller. Without seeing your kernel I'm not sure if this would help or not though.

Long compile time (infinte loop) | Altera Community

13 Replies

Altera_Forum
Honored Contributor
11 years ago
The first stage of compilation completes successfully. I think I was confused. By 14.0 update 1 you just mean the 14.0 release? This is what I'm using.

For me, the second Quartus stage of compilation is what takes days (over 5 days before I killed it). This may be a reasonable time, and I'm just being impatient, but my utilization is around 70% so I expected this was some sort of error.
Altera_Forum
Honored Contributor
11 years ago
No, this is not normal. There are no rules, but my experience is that quartus compilation typically take < 10-12 hours, perhaps a little longer if the chip is close to being full.

This is not directly related to the OpenCL compiler. Other Altera forums may have more information about this kind of issues.

In the meantime, you can perhaps try to reduce the resource usage of your design, or try compiling for a smaller problem size first to make sure that quartus works fine.
Altera_Forum
Honored Contributor
11 years ago
I've verified shorter compile times and correct execution for smaller instances of the problem.

Thanks for the info/advice Outku,

-Jack

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Long compile time (infinte loop)

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