Makefile: add check-parallel target for faster shellcheck

Add a new check-parallel target that utilizes all available CPUs to
run shellcheck in parallel on test files, significantly reducing
validation time from ~40s to ~11s on a 48-core system.

The original check target remains unchanged for compatibility.

blktests (master) # vim 0001-Makefile-add-check-parallel-target-for-faster-shellc.patch
blktests (master) # time make check
shellcheck -x -e SC2119 -f gcc check common/* \
    tests/*/rc tests/*/[0-9]*[0-9] src/*.sh
check:634:20: note: Double quote to prevent globbing and word splitting. [SC2086]
check:667:20: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:447:5: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:453:6: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:553:42: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:554:28: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:556:28: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:557:28: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:558:23: note: Double quote to prevent globbing and word splitting. [SC2086]
tests/pr.bk/001:9:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/001:11:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/001:12:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/002:8:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/002:10:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/002:11:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/003:8:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/003:10:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/003:11:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/004:8:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/004:10:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/004:11:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/005:8:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/005:10:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/005:11:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/006:9:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/006:11:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/006:12:1: warning: TIMED appears unused. Verify use (or export if used externally). [SC2034]
make: *** [Makefile:22: check] Error 1

real    3m43.712s
user    3m38.640s
sys    0m3.321s
Running shellcheck with 48 parallel jobs...
tests/pr.bk/005:8:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/005:10:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/005:11:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/006:9:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/006:11:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/006:12:1: warning: TIMED appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/001:9:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/001:11:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/001:12:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/002:8:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/002:10:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/002:11:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/004:8:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/004:10:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/004:11:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/003:8:3: note: Not following: tests/pr/rc: openBinaryFile: does not exist (No such file or directory) [SC1091]
tests/pr.bk/003:10:1: warning: DESCRIPTION appears unused. Verify use (or export if used externally). [SC2034]
tests/pr.bk/003:11:1: warning: QUICK appears unused. Verify use (or export if used externally). [SC2034]
check:634:20: note: Double quote to prevent globbing and word splitting. [SC2086]
check:667:20: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:447:5: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:453:6: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:553:42: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:554:28: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:556:28: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:557:28: note: Double quote to prevent globbing and word splitting. [SC2086]
common/nvme:558:23: note: Double quote to prevent globbing and word splitting. [SC2086]
make: *** [Makefile:30: check-parallel] Error 1

real    0m22.464s
user    7m24.518s
sys    0m11.703s

10.0x faster than sequential
  Concrete numbers:
  - make check: 223.7s (3m43.7s)
  - make check-parallel: 22.5s

Signed-off-by: Chaitanya Kulkarni <[email protected]>
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>

Author: ChaitanayaKulkarni

Makefile

@@ -16,6 +16,7 @@ install:
 # SC2119: "Use foo "$@" if function's $1 should mean script's $1". False
 # positives on helpers like _init_scsi_debug.
 SHELLCHECK_EXCLUDE := SC2119
+NPROCS := $(shell nproc)
 
 check:
 	shellcheck -x -e $(SHELLCHECK_EXCLUDE) -f gcc check common/* \
@@ -24,4 +25,15 @@ check:
 	! grep TODO tests/*/rc tests/*/[0-9]*[0-9]
 	! find -L -name '*.out' -perm /u=x+g=x+o=x -printf '%p is executable\n' | grep .
 
-.PHONY: all check install
+check-parallel:
+	@echo "Running shellcheck with $(NPROCS) parallel jobs..."
+	@ret=0; \
+	find tests -type f -name '[0-9]*[0-9]' | \
+		xargs -P $(NPROCS) -n 1 shellcheck -x -e $(SHELLCHECK_EXCLUDE) -f gcc || ret=1; \
+	shellcheck -x -e $(SHELLCHECK_EXCLUDE) -f gcc check common/* tests/*/rc src/*.sh || ret=1; \
+	shellcheck --exclude=$(SHELLCHECK_EXCLUDE),SC2154 --format=gcc new || ret=1; \
+	grep TODO tests/*/rc tests/*/[0-9]*[0-9] && ret=1; \
+	find -L -name '*.out' -perm /u=x+g=x+o=x -printf '%p is executable\n' | grep . && ret=1; \
+	exit $$ret
+
+.PHONY: all check check-parallel install