Merge branch 'nk/diff-files-vs-fsmonitor'

"git diff" and other commands that share the same machinery to
compare with working tree files have been taught to take advantage
of the fsmonitor data when available.

* nk/diff-files-vs-fsmonitor:
  p7519-fsmonitor: add a git add benchmark
  p7519-fsmonitor: refactor to avoid code duplication
  perf lint: add make test-lint to perf tests
  t/perf: add fsmonitor perf test for git diff
  t/perf/p7519-fsmonitor.sh: warm cache on first git status
  t/perf/README: elaborate on output format
  fsmonitor: use fsmonitor data in `git diff`

6 files changed, 81 insertions, 50 deletions

diff --git a/diff-lib.c b/diff-lib.c
index d18a118249..082e249fc3 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -98,6 +98,8 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 
 	diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
 
+	refresh_fsmonitor(istate);
+
 	if (diff_unmerged_stage < 0)
 		diff_unmerged_stage = 2;
 	entries = istate->cache_nr;
@@ -198,8 +200,17 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 		if (ce_uptodate(ce) || ce_skip_worktree(ce))
 			continue;
 
-		/* If CE_VALID is set, don't look at workdir for file removal */
-		if (ce->ce_flags & CE_VALID) {
+		/*
+		 * When CE_VALID is set (via "update-index --assume-unchanged"
+		 * or via adding paths while core.ignorestat is set to true),
+		 * the user has promised that the working tree file for that
+		 * path will not be modified.  When CE_FSMONITOR_VALID is true,
+		 * the fsmonitor knows that the path hasn't been modified since
+		 * we refreshed the cached stat information.  In either case,
+		 * we do not have to stat to see if the path has been removed
+		 * or modified.
+		 */
+		if (ce->ce_flags & (CE_VALID | CE_FSMONITOR_VALID)) {
 			changed = 0;
 			newmode = ce->ce_mode;
 		} else {
diff --git a/t/Makefile b/t/Makefile
index c83fd18861..882d26eee3 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -34,6 +34,7 @@ CHAINLINTTMP_SQ = $(subst ','\'',$(CHAINLINTTMP))
 T = $(sort $(wildcard t[0-9][0-9][0-9][0-9]-*.sh))
 TGITWEB = $(sort $(wildcard t95[0-9][0-9]-*.sh))
 THELPERS = $(sort $(filter-out $(T),$(wildcard *.sh)))
+TPERF = $(sort $(wildcard perf/p[0-9][0-9][0-9][0-9]-*.sh))
 CHAINLINTTESTS = $(sort $(patsubst chainlint/%.test,%,$(wildcard chainlint/*.test)))
 CHAINLINT = sed -f chainlint.sed
 
@@ -81,17 +82,17 @@ test-lint: test-lint-duplicates test-lint-executable test-lint-shell-syntax \
 	test-lint-filenames
 
 test-lint-duplicates:
-	@dups=`echo $(T) | tr ' ' '\n' | sed 's/-.*//' | sort | uniq -d` && \
+	@dups=`echo $(T) $(TPERF) | tr ' ' '\n' | sed 's/-.*//' | sort | uniq -d` && \
 		test -z "$$dups" || { \
 		echo >&2 "duplicate test numbers:" $$dups; exit 1; }
 
 test-lint-executable:
-	@bad=`for i in $(T); do test -x "$$i" || echo $$i; done` && \
+	@bad=`for i in $(T) $(TPERF); do test -x "$$i" || echo $$i; done` && \
 		test -z "$$bad" || { \
 		echo >&2 "non-executable tests:" $$bad; exit 1; }
 
 test-lint-shell-syntax:
-	@'$(PERL_PATH_SQ)' check-non-portable-shell.pl $(T) $(THELPERS)
+	@'$(PERL_PATH_SQ)' check-non-portable-shell.pl $(T) $(THELPERS) $(TPERF)
 
 test-lint-filenames:
 	@# We do *not* pass a glob to ls-files but use grep instead, to catch
diff --git a/t/perf/Makefile b/t/perf/Makefile
index 8c47155a7c..fcb0e8865e 100644
--- a/t/perf/Makefile
+++ b/t/perf/Makefile
@@ -1,7 +1,7 @@
 -include ../../config.mak
 export GIT_TEST_OPTIONS
 
-all: perf
+all: test-lint perf
 
 perf: pre-clean
 	./run
@@ -12,4 +12,7 @@ pre-clean:
 clean:
 	rm -rf build "trash directory".* test-results
 
+test-lint:
+	$(MAKE) -C .. test-lint
+
 .PHONY: all perf pre-clean clean
diff --git a/t/perf/README b/t/perf/README
index bd649afa97..fb9127a66f 100644
--- a/t/perf/README
+++ b/t/perf/README
@@ -28,6 +28,8 @@ the tests on the current git repository.
     7810.3: grep --cached, cheap regex       3.07(3.02+0.25)
     7810.4: grep --cached, expensive regex   9.39(30.57+0.24)
 
+Output format is in seconds "Elapsed(User + System)"
+
 You can compare multiple repositories and even git revisions with the
 'run' script:
 
diff --git a/t/perf/p3400-rebase.sh b/t/perf/p3400-rebase.sh
index d202aaed06..7a0bb29448 100755
--- a/t/perf/p3400-rebase.sh
+++ b/t/perf/p3400-rebase.sh
@@ -9,16 +9,16 @@ test_expect_success 'setup rebasing on top of a lot of changes' '
 	git checkout -f -B base &&
 	git checkout -B to-rebase &&
 	git checkout -B upstream &&
-	for i in $(seq 100)
+	for i in $(test_seq 100)
 	do
 		# simulate huge diffs
 		echo change$i >unrelated-file$i &&
-		seq 1000 >>unrelated-file$i &&
+		test_seq 1000 >>unrelated-file$i &&
 		git add unrelated-file$i &&
 		test_tick &&
 		git commit -m commit$i unrelated-file$i &&
 		echo change$i >unrelated-file$i &&
-		seq 1000 | tac >>unrelated-file$i &&
+		test_seq 1000 | tac >>unrelated-file$i &&
 		git add unrelated-file$i &&
 		test_tick &&
 		git commit -m commit$i-reverse unrelated-file$i ||
diff --git a/t/perf/p7519-fsmonitor.sh b/t/perf/p7519-fsmonitor.sh
index def7ecdbc7..fb20fe0937 100755
--- a/t/perf/p7519-fsmonitor.sh
+++ b/t/perf/p7519-fsmonitor.sh
@@ -114,63 +114,77 @@ test_expect_success "setup for fsmonitor" '
 	fi &&
 
 	git config core.fsmonitor "$INTEGRATION_SCRIPT" &&
-	git update-index --fsmonitor
+	git update-index --fsmonitor &&
+	mkdir 1_file 10_files 100_files 1000_files 10000_files &&
+	for i in $(test_seq 1 10); do touch 10_files/$i; done &&
+	for i in $(test_seq 1 100); do touch 100_files/$i; done &&
+	for i in $(test_seq 1 1000); do touch 1000_files/$i; done &&
+	for i in $(test_seq 1 10000); do touch 10000_files/$i; done &&
+	git add 1_file 10_files 100_files 1000_files 10000_files &&
+	git commit -m "Add files" &&
+	git status  # Warm caches
 '
 
-if test -n "$GIT_PERF_7519_DROP_CACHE"; then
-	test-tool drop-caches
-fi
+test_perf_w_drop_caches () {
+	if test -n "$GIT_PERF_7519_DROP_CACHE"; then
+		test-tool drop-caches
+	fi
 
-test_perf "status (fsmonitor=$INTEGRATION_SCRIPT)" '
-	git status
-'
+	test_perf "$@"
+}
 
-if test -n "$GIT_PERF_7519_DROP_CACHE"; then
-	test-tool drop-caches
-fi
+test_fsmonitor_suite() {
+	test_perf_w_drop_caches "status (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git status
+	'
 
-test_perf "status -uno (fsmonitor=$INTEGRATION_SCRIPT)" '
-	git status -uno
-'
+	test_perf_w_drop_caches "status -uno (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git status -uno
+	'
 
-if test -n "$GIT_PERF_7519_DROP_CACHE"; then
-	test-tool drop-caches
-fi
+	test_perf_w_drop_caches "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git status -uall
+	'
 
-test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
-	git status -uall
-'
+	test_perf_w_drop_caches "diff (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git diff
+	'
 
-test_expect_success "setup without fsmonitor" '
-	unset INTEGRATION_SCRIPT &&
-	git config --unset core.fsmonitor &&
-	git update-index --no-fsmonitor
-'
+	test_perf_w_drop_caches "diff -- 0_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git diff -- 1_file
+	'
 
-if test -n "$GIT_PERF_7519_DROP_CACHE"; then
-	test-tool drop-caches
-fi
+	test_perf_w_drop_caches "diff -- 10_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git diff -- 10_files
+	'
 
-test_perf "status (fsmonitor=$INTEGRATION_SCRIPT)" '
-	git status
-'
+	test_perf_w_drop_caches "diff -- 100_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git diff -- 100_files
+	'
 
-if test -n "$GIT_PERF_7519_DROP_CACHE"; then
-	test-tool drop-caches
-fi
+	test_perf_w_drop_caches "diff -- 1000_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git diff -- 1000_files
+	'
 
-test_perf "status -uno (fsmonitor=$INTEGRATION_SCRIPT)" '
-	git status -uno
-'
+	test_perf_w_drop_caches "diff -- 10000_files (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git diff -- 10000_files
+	'
 
-if test -n "$GIT_PERF_7519_DROP_CACHE"; then
-	test-tool drop-caches
-fi
+	test_perf_w_drop_caches "add (fsmonitor=$INTEGRATION_SCRIPT)" '
+		git add  --all
+	'
+}
+
+test_fsmonitor_suite
 
-test_perf "status -uall (fsmonitor=$INTEGRATION_SCRIPT)" '
-	git status -uall
+test_expect_success "setup without fsmonitor" '
+	unset INTEGRATION_SCRIPT &&
+	git config --unset core.fsmonitor &&
+	git update-index --no-fsmonitor
 '
 
+test_fsmonitor_suite
+
 if test_have_prereq WATCHMAN
 then
 	watchman watch-del "$GIT_WORK_TREE" >/dev/null 2>&1 &&