# Improve Quartus partial compile or recompile time

I run Altera Quartus, and I'm using the SignalTap logic analyzer on a Max 10 FPGA. It takes tens of minutes to compile, and every time I'd like to add a signal to SignalTap, I have to compile again. The rapid-recompile button is always grayed out, I don't even know what it does, I've never had the option. A lot of times, I'm not changing my design just SignalTap, but Quartus wants to recompile everything which seems like a waste of time. Is there a way speed up the compile time (or changes to only apply to SignalTap)? Using Quartus 15.1

• Are you using the free version? I think this kind of optimizations are enabled on the full versions only. – Eugene Sh. Jun 13 '16 at 20:30
• It's the way it is. SignalTap requires additional signals to be compiled in, and if you are using pre-synthesis signal names, the design needs to be recompiled to ensure they are present and not optimised away. I know how you feel - my current design takes 3 hours to compile, so it's very much a case of simulate the heck out of everything first and use signalTap as a last resort. – Tom Carpenter Jun 13 '16 at 20:43
• What Quartus version are you using? – Claudio Avi Chami Jun 14 '16 at 4:07
• Tom's observation is the key. You can select post fit nodes in signal tap and then turn on incremental compilation. The node names may look very long and incomprehensible at first. But you can get used to it. – shparekh Jun 14 '16 at 4:41
• Forgot to add the link - quartushelp.altera.com/14.0/mergedProjects/program/ela/… – shparekh Jun 14 '16 at 4:45

I've listed some useful flags to make Quartus synthesize faster if you don't care about fully optimizing your results:

set_global_assignment  -name PHYSICAL_SYNTHESIS_EFFORT  FAST


Specifies the amount of effort, in terms of compile time, physical synthesis should use. Fast uses less compile time but may reduce the performance gain that physical synthesis is able to achieve.

set_global_assignment  -name FITTER_EFFORT              FAST_FIT


Fast Fit decreases optimization effort to reduce compilation time, which may degrade design performance.

set_global_assignment  -name SYNTHESIS_EFFORT           FAST


Note that this has the caveat below, although I tend to see overall faster runs.

When set to Fast, some steps are omitted to accomplish synthesis more quickly; however, there may be some performance and resource cost. Altera recommends setting this option to Fast only when running an early timing estimate. Running a "fast" synthesis produces a netlist that is slightly harder for the Fitter to route, thus making the overall fitting process slower, which negates any performance increases achieved as a result of the "fast" synthesis.

execute_flow -compile


Use:

execute_flow -implement


Option to run compilation up to route stage and skipping all time intensive algorithms after.

In a meeting with Intel/Altera engineers, using -implement this was ball-parked to be about 20% faster than -compile, and came recommended when iterating on timing-closure results.

If anyone has other recommended, please edit this comment so we can develop a list.

The best/cheapest way to improve compile time is to buy a processor with more cores. Since even the free version of Quartus has multiprocessor compile capability at certain stages of the hardware compile. A new processor will run a few hundred dollars where buying the full version with the partial compile is thousands.

Do what the Java programmers do these days and ask for more hardware instead of improving software.