Merge tag 'lkmm-scripting.2023.04.07a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull Linux Kernel Memory Model scripting updates from Paul McKenney:
 "This improves litmus-test documentation and improves the ability to do
  before/after tests on the https://github.com/paulmckrcu/litmus repo"

* tag 'lkmm-scripting.2023.04.07a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (32 commits)
  tools/memory-model: Remove out-of-date SRCU documentation
  tools/memory-model: Document LKMM test procedure
  tools/memory-model: Use "grep -E" instead of "egrep"
  tools/memory-model: Use "-unroll 0" to keep --hw runs finite
  tools/memory-model: Make judgelitmus.sh handle scripted Result: tag
  tools/memory-model: Add data-race capabilities to judgelitmus.sh
  tools/memory-model: Add checktheselitmus.sh to run specified litmus tests
  tools/memory-model: Repair parseargs.sh header comment
  tools/memory-model:  Add "--" to parseargs.sh for additional arguments
  tools/memory-model: Make history-check scripts use mselect7
  tools/memory-model: Make checkghlitmus.sh use mselect7
  tools/memory-model: Fix scripting --jobs argument
  tools/memory-model: Implement --hw support for checkghlitmus.sh
  tools/memory-model: Add -v flag to jingle7 runs
  tools/memory-model: Make runlitmus.sh check for jingle errors
  tools/memory-model: Allow herd to deduce CPU type
  tools/memory-model: Keep assembly-language litmus tests
  tools/memory-model: Move from .AArch64.litmus.out to .litmus.AArch.out
  tools/memory-model: Make runlitmus.sh generate .litmus.out for --hw
  tools/memory-model: Split runlitmus.sh out of checklitmus.sh
  ...

1 files changed, 44 insertions, 4 deletions

diff --git a/tools/memory-model/scripts/README b/tools/memory-model/scripts/README
index 095c7eb36f9f..fb39bd0fd1b9 100644
--- a/tools/memory-model/scripts/README
+++ b/tools/memory-model/scripts/README
@@ -27,6 +27,14 @@ checklitmushist.sh
 checklitmus.sh
 
 	Check a single litmus test against its "Result:" expected result.
+	Not intended to for manual use.
+
+checktheselitmus.sh
+
+	Check the specified list of litmus tests against their "Result:"
+	expected results.  This takes optional parseargs.sh arguments,
+	followed by "--" followed by pathnames starting from the current
+	directory.
 
 cmplitmushist.sh
 
@@ -43,10 +51,10 @@ initlitmushist.sh
 
 judgelitmus.sh
 
-	Given a .litmus file and its .litmus.out herd7 output, check the
-	.litmus.out file against the .litmus file's "Result:" comment to
-	judge whether the test ran correctly.  Not normally run manually,
-	provided instead for use by other scripts.
+	Given a .litmus file and its herd7 output, check the output file
+	against the .litmus file's "Result:" comment to judge whether
+	the test ran correctly.  Not normally run manually, provided
+	instead for use by other scripts.
 
 newlitmushist.sh
 
@@ -68,3 +76,35 @@ runlitmushist.sh
 README
 
 	This file
+
+Testing a change to LKMM might go as follows:
+
+	# Populate expected results without that change, and
+	# runs for about an hour on an 8-CPU x86 system:
+	scripts/initlitmushist.sh --timeout 10m --procs 10
+	# Incorporate the change:
+	git am -s -3 /path/to/patch # Or whatever it takes.
+
+	# Test the new version of LKMM as follows...
+
+	# Runs in seconds, good smoke test:
+	scripts/checkalllitmus.sh
+
+	# Compares results to those produced by initlitmushist.sh,
+	# and runs for about an hour on an 8-CPU x86 system:
+	scripts/checklitmushist.sh --timeout 10m --procs 10
+
+	# Checks results against Result tags, runs in minutes:
+	scripts/checkghlitmus.sh --timeout 10m --procs 10
+
+The checkghlitmus.sh should not report errors in cases where the
+checklitmushist.sh script did not also report a change.  However,
+this check is nevertheless valuable because it can find errors in the
+original version of LKMM.  Note however, that given the above procedure,
+an error in the original LKMM version that is fixed by the patch will
+be reported both as a mismatch by checklitmushist.sh and as an error
+by checkghlitmus.sh.  One exception to this rule of thumb is when the
+test fails completely on the original version of LKMM and passes on the
+new version.  In this case, checklitmushist.sh will report a mismatch
+and checkghlitmus.sh will report success.  This happens when the change
+to LKMM introduces a new primitive for which litmus tests already existed.