ci: macos: Reduce test concurrency

Test performance regresses noticably when using all cores. This is more
pronounced with meson than with autoconf, presumably because meson will
schedule the "full number" of tests more consistently.  8 seems to work
OK.

Discussion: https://postgr.es/m/20220927040208.l3shfcidovpzqxfh@awork3.anarazel.de
Backpatch: 15-, where CI was introduced

diff --git a/.cirrus.yml b/.cirrus.yml
index d7f00cfb970df6bbf10a3a2173d222c78c2ce9ce..825028f059a031fd500de7fbfe5294f44ef5c409 100644 (file)
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -294,7 +294,10 @@ task:
   env:
     CPUS: 12 # always get that much for cirrusci macOS instances
     BUILD_JOBS: $CPUS
-    TEST_JOBS: $CPUS # already fast enough to not be worth tuning
+    # Test performance regresses noticably when using all cores. 8 seems to
+    # work OK. See
+    # https://postgr.es/m/20220927040208.l3shfcidovpzqxfh%40awork3.anarazel.de
+    TEST_JOBS: 8
 
     CIRRUS_WORKING_DIR: ${HOME}/pgsql/
     CCACHE_DIR: ${HOME}/ccache