Observed unexpected behavior whilst developing new module and tests:
test_proc or proc (procA) can affect execution of another test_proc (procB)
order of spawn expressions in test_proc affects operation
I am not sure if these are related to each other, but I was unable to reproduce the issue on a smaller test case. Faulty code is on branch bug-procs-order, rebased on commit 609a7ab89d96d2a7396d2418d00d30e4cb57b119
I executed the tests with a prepared rule:
bazel run //xls/modules/axi4/dma:test_fifo
Previously, I had opened an issue related to order of statements #1191, which may be related.
This issue is a blocker for #1208 .
My design
There are:
2 test_proc, which interact with top-level entity FIFO
FIFO spawns FIFORAM, and 2 processes to manage input and output: Reader, Writer
Process named fifo_synth is a wrapper to set parametrics to constant values and use it to generate verilog
Side-effect on another test_proc
Issue:
If only test_fifo is present in the file, it ends successfully, so I assume the test is OK.
Then I added a second test test_double_fifo_gpf, which cause the the original proc test_fifo to never end and as a result be killed by the runner (internal error: DEADLINE_EXCEEDED: Exceeded limit of 100000 proc ticks before terminating)
The same exact thing happens if test_fifo is present and fifo_synth is uncommented.
In test_double_fifo_gpf I spawn 2 FIFOs to test a more complicated scenario and it turns out that the order of spawn expressions has effect on the execution.
This is almost what I expected whilst developing. There are writes to first FIFO and I expect that later data will go through the GPF and into the 2nd FIFO. Thanks to the trace_channels option, I can confirm that a valid request is sent to RAM and my processes hang on awaiting a response from RAM.
Introduction
Observed unexpected behavior whilst developing new module and tests:
test_proc
orproc
(procA) can affect execution of anothertest_proc
(procB)spawn
expressions intest_proc
affects operationI am not sure if these are related to each other, but I was unable to reproduce the issue on a smaller test case. Faulty code is on branch bug-procs-order, rebased on commit 609a7ab89d96d2a7396d2418d00d30e4cb57b119
I executed the tests with a prepared rule:
Previously, I had opened an issue related to order of statements #1191, which may be related. This issue is a blocker for #1208 .
My design
There are:
test_proc
, which interact with top-level entity FIFOFIFORAM
, and 2 processes to manage input and output:Reader
,Writer
fifo_synth
is a wrapper to set parametrics to constant values and use it to generate verilogSide-effect on another
test_proc
Issue:
test_fifo
is present in the file, it ends successfully, so I assume the test is OK.test_double_fifo_gpf
, which cause the the original proctest_fifo
to never end and as a result be killed by the runner (internal error: DEADLINE_EXCEEDED: Exceeded limit of 100000 proc ticks before terminating)test_fifo
is present andfifo_synth
is uncommented.Link to code
Order of
spawn
expressionsIn
test_double_fifo_gpf
I spawn 2 FIFOs to test a more complicated scenario and it turns out that the order ofspawn
expressions has effect on the execution.Link to code
Order #1
I trace the state of 2 RAMs in 2 FIFOs
1st FIFO:
2nd FIFO:
This is almost what I expected whilst developing. There are writes to first FIFO and I expect that later data will go through the GPF and into the 2nd FIFO. Thanks to the
trace_channels
option, I can confirm that a valid request is sent to RAM and my processes hang on awaiting a response from RAM.Why would either 1 or 2 RAMs hang indefinitely?
Order #2 (reverse of #1)
I trace the state of 2 RAMs in 2 FIFOs
1st FIFO:
2nd FIFO:
Both are always empty, not even the first write occurs anymore.
Can you please help me with understanding/debugging why this occurs?