Can't figure out how to run tests in parallel

[sgraf812]

The test.hs script calls make with -j set to the number of capabilities of the script process. I can't seem to figure out how to increase that number; at the least it does not pick up the number of cpu cores on my machine automatically.
It's a bit annoying, but not too bad: I can just change the script to use -j7 (I have 6 cores). Nevertheless, the script seems a bit misleading.

[andreasabel]

happy/test.hs

Lines 6 to 9 in abcd8c0

	main = do
	let jFlag = "-j" ++ show numCapabilities
	let cmd = ["make", jFlag, "-k", "-C", "tests", "clean", "all"]
	system (intercalate " " cmd) >>= exitWith

Have you tried to set it via the +RTS -N flag, as described in the docs ?
https://hackage.haskell.org/package/base-4.19.0.0/docs/GHC-Conc.html#v:numCapabilities

[sgraf812]

I have tried, but it is unclear to me where I should pass it. Is it cabal test +RTS -N7? No (I tried). More likely I'll have to do cabal test --test-options="+RTS -N7 -RTS" but that errors out with ... aha, a useful message:

tests: the flag -N7 requires the program to be built with -threaded

Fix incoming.