[PATCH v2] perf tests: Improvements to build-test performance
From: Ian Rogers
Date: Thu Sep 03 2026 - 01:00:33 EST
Replace hardcoded 'make' calls with '$(MAKE)' within tests/make to
ensure GNU Make jobserver file descriptors are properly inherited by
nested builds.
Additionally, remove the 'unexport MAKEFLAGS' from
tools/perf/Makefile. This hack was originally added to prevent the
wrapper's internal '-j$(JOBS)' override from crashing when parent
jobserver tokens were present. Instead, use proper GNU Make
conditionals to check for '-j' or 'jobserver' strings within
MAKEFLAGS. If a jobserver is already orchestrating the build,
gracefully back off and let GNU Make manage parallelism natively.
Finally, optimize the 'out' target (which processes 'run_O'
out-of-tree builds) by stripping sequential bottlenecks like $(call
clean) from isolated tmp directories, and wrapping the target list in
a parallel sub-make call.
These combined changes enable 'build-test' out-of-tree targets to
build completely concurrently without severing jobserver tokens.
Unscientifically measured the change lowered the build-test from
around 15 minutes to 10 minutes on a 28 threaded Alderlake CPU. Fixing
the jobserver issues meant the machine remained somewhat usable while
running the test.
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
Assisted-by: Antigravity:gemini-3.1-pro
---
v2:
- Re-structured build-test array in tools/perf/Makefile into explicit
sequential $(MAKE) passes. This prevents in-tree targets (make_static,
etc.) from racing to directory corruption when exposed to native
jobservers.
- Added '+' prefix to recipe modifiers in tests/make to prevent jobserver
FDs from being stripped before sub-shell evaluation.
- Replaced hardcoded -j$(cores) limits in the 'out' sub-make step with
dynamic jobserver boundary detection to prevent fork-bomb override
collisions.
- Restored missing $(call clean) steps via O_CLEAN conditionals to prevent
in-tree polluted runs from breaking out-of-tree sequences.
- Removed unconditionally appended $(FEATURES_DUMP_FILE) target restrictions
from 'out' that threw "No rule to make target" errors on unhandled tests.
- Fixed 'test_dest_files' to check [ ! -f ] instead of [ ! -x ], removing
long-standing ghost warnings for non-executable mode-644 targets
like etc/bash_completion.d/perf.
- Fixed cosmetic string formatting bugs in GNU Make's print_msg banner
output.
---
tools/perf/Makefile | 35 ++++++++++++++++++++++-------------
tools/perf/tests/make | 42 ++++++++++++++++++++++++------------------
2 files changed, 46 insertions(+), 31 deletions(-)
diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 5b713837eede..2cbf4cb5f093 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -14,23 +14,29 @@
.SUFFIXES:
#
-# We don't want to pass along options like -j:
+# If no parallel build was requested, do a parallel build with multiple jobs,
+# based on the number of CPUs online in this system: 'make -j8' on an 8-CPU
+# system, etc.
#
-unexport MAKEFLAGS
-
-#
-# Do a parallel build with multiple jobs, based on the number of CPUs online
-# in this system: 'make -j8' on a 8-CPU system, etc.
+# If MAKEFLAGS contains '-j' or 'jobserver', JOBS is intentionally left
+# uninitialized so the native GNU Make jobserver can seamlessly control the
+# parallel bounds of the build.
#
# (To override it, run 'make JOBS=1' and similar.)
#
-ifeq ($(JOBS),)
- JOBS := $(shell (getconf _NPROCESSORS_ONLN || grep -E -c '^processor|^CPU[0-9]' /proc/cpuinfo) 2>/dev/null)
- ifeq ($(JOBS),0)
- JOBS := 1
+ifeq ($(findstring -j,$(MAKEFLAGS)),)
+ ifeq ($(findstring jobserver,$(MAKEFLAGS)),)
+ ifeq ($(JOBS),)
+ JOBS := $(shell (getconf _NPROCESSORS_ONLN || grep -E -c '^processor|^CPU[0-9]' /proc/cpuinfo) 2>/dev/null)
+ ifeq ($(JOBS),0)
+ JOBS := 1
+ endif
+ endif
+ PARALLEL_OPT := -j$(JOBS)
endif
endif
+
#
# Only pass canonical directory names as the output directory:
#
@@ -58,11 +64,11 @@ else
endif
define print_msg
- @printf ' BUILD: Doing '\''make \033[33m-j'$(JOBS)'\033[m'\'' $(BUILD_TYPE) build\n'
+ @printf ' BUILD: Doing '\''make\033[33m%s\033[m'\'' $(BUILD_TYPE) build\n' "$(if $(JOBS), -j$(JOBS),)"
endef
define make
- @$(MAKE) -f Makefile.perf --no-print-directory -j$(JOBS) O=$(FULL_O) $(SET_DEBUG) $@
+ @$(MAKE) -f Makefile.perf --no-print-directory $(PARALLEL_OPT) O=$(FULL_O) $(SET_DEBUG) $@
endef
#
@@ -106,7 +112,10 @@ clean:
# make -C tools/perf -f tests/make
#
build-test:
- @$(MAKE) SHUF=1 -f tests/make REUSE_FEATURES_DUMP=1 MK=Makefile SET_PARALLEL=1 --no-print-directory tarpkg make_static make_with_gtk2 out
+ @$(MAKE) SHUF=1 -f tests/make REUSE_FEATURES_DUMP=1 MK=Makefile SET_PARALLEL=1 --no-print-directory tarpkg
+ @$(MAKE) SHUF=1 -f tests/make REUSE_FEATURES_DUMP=1 MK=Makefile SET_PARALLEL=1 --no-print-directory make_static
+ @$(MAKE) SHUF=1 -f tests/make REUSE_FEATURES_DUMP=1 MK=Makefile SET_PARALLEL=1 --no-print-directory make_with_gtk2
+ @$(MAKE) SHUF=1 -f tests/make REUSE_FEATURES_DUMP=1 MK=Makefile SET_PARALLEL=1 --no-print-directory out
build-test-tarball:
@$(MAKE) -f tests/make REUSE_FEATURES_DUMP=1 MK=Makefile SET_PARALLEL=1 --no-print-directory out
diff --git a/tools/perf/tests/make b/tools/perf/tests/make
index d2c2f526e1db..d1d99f5a85ae 100644
--- a/tools/perf/tests/make
+++ b/tools/perf/tests/make
@@ -28,15 +28,17 @@ endif
PARALLEL_OPT=
ifeq ($(SET_PARALLEL),1)
- ifeq ($(JOBS),)
- cores := $(shell (getconf _NPROCESSORS_ONLN || grep -E -c '^processor|^CPU[0-9]' /proc/cpuinfo) 2>/dev/null)
- ifeq ($(cores),0)
- cores := 1
+ ifeq ($(findstring jobserver,$(MAKEFLAGS))$(findstring -j,$(MAKEFLAGS)),)
+ ifeq ($(JOBS),)
+ cores := $(shell (getconf _NPROCESSORS_ONLN || grep -E -c '^processor|^CPU[0-9]' /proc/cpuinfo) 2>/dev/null)
+ ifeq ($(cores),0)
+ cores := 1
+ endif
+ else
+ cores=$(JOBS)
endif
- else
- cores=$(JOBS)
+ PARALLEL_OPT="-j$(cores)"
endif
- PARALLEL_OPT="-j$(cores)"
endif
# As per kernel Makefile, avoid funny character set dependencies
@@ -230,7 +232,7 @@ test_make_util_pmu_bison_o := test -f $(PERF_O)/util/pmu-bison.o
define test_dest_files
for file in $(1); do \
- if [ ! -x $$TMP_DEST/$$file ]; then \
+ if [ ! -f $$TMP_DEST/$$file ]; then \
echo " failed to find: $$file"; \
fi \
done
@@ -310,7 +312,7 @@ clean := @(cd $(PERF); $(MAKE_F) -s $(O_OPT) clean >/dev/null && $(MAKE) -s $(O_
$(run):
$(call clean)
- @TMP_DEST=$$(mktemp -d); \
+ +@TMP_DEST=$$(mktemp -d); \
cmd="cd $(PERF) && $(MAKE_F) $($@) $(PARALLEL_OPT) $(O_OPT) DESTDIR=$$TMP_DEST"; \
printf "%*.*s: %s\n" $(max_width) $(max_width) "$@" "$$cmd" && echo $$cmd > $@ && \
( eval $$cmd ) >> $@ 2>&1; \
@@ -320,7 +322,7 @@ $(run):
make_with_gtk2:
$(call clean)
- @TMP_DEST=$$(mktemp -d); \
+ +@TMP_DEST=$$(mktemp -d); \
cmd="cd $(PERF) && $(MAKE_F) $($@) $(PARALLEL_OPT) $(O_OPT) DESTDIR=$$TMP_DEST"; \
printf "%*.*s: %s\n" $(max_width) $(max_width) "$@" "$$cmd" && echo $$cmd > $@ && \
( eval $$cmd ) >> $@ 2>&1; \
@@ -330,7 +332,7 @@ make_with_gtk2:
make_static:
$(call clean)
- @TMP_DEST=$$(mktemp -d); \
+ +@TMP_DEST=$$(mktemp -d); \
cmd="cd $(PERF) && $(MAKE_F) $($@) $(PARALLEL_OPT) $(O_OPT) DESTDIR=$$TMP_DEST"; \
printf "%*.*s: %s\n" $(max_width) $(max_width) "$@" "$$cmd" && echo $$cmd > $@ && \
( eval $$cmd ) >> $@ 2>&1; \
@@ -339,8 +341,10 @@ make_static:
rm -rf $@ $$TMP_DEST || (cat $@ ; false)
$(run_O):
+ifneq ($(O_CLEAN),0)
$(call clean)
- @TMP_O=$$(mktemp -d); \
+endif
+ +@TMP_O=$$(mktemp -d); \
TMP_DEST=$$(mktemp -d); \
cmd="cd $(PERF) && $(MAKE_F) $($(patsubst %_O,%,$@)) $(PARALLEL_OPT) O=$$TMP_O DESTDIR=$$TMP_DEST"; \
printf "%*.*s: %s\n" $(max_width) $(max_width) "$@" "$$cmd" && echo $$cmd > $@ && \
@@ -363,18 +367,18 @@ endif
make_kernelsrc:
@echo "- make -C <kernelsrc> $(PARALLEL_OPT) $(K_O_OPT) tools/perf"
$(call clean); \
- (make -C ../.. $(PARALLEL_OPT) $(K_O_OPT) tools/perf) > $@ 2>&1 && \
+ ($(MAKE) -C ../.. $(PARALLEL_OPT) $(K_O_OPT) tools/perf) > $@ 2>&1 && \
test -x $(KERNEL_O)/tools/perf/perf && rm -f $@ || (cat $@ ; false)
make_kernelsrc_tools:
@echo "- make -C <kernelsrc>/tools $(PARALLEL_OPT) $(K_O_OPT) perf"
$(call clean); \
- (make -C ../../tools $(PARALLEL_OPT) $(K_O_OPT) perf) > $@ 2>&1 && \
+ ($(MAKE) -C ../../tools $(PARALLEL_OPT) $(K_O_OPT) perf) > $@ 2>&1 && \
test -x $(KERNEL_O)/tools/perf/perf && rm -f $@ || (cat $@ ; false)
make_libperf:
@echo "- make -C lib";
- make -C lib clean >$@ 2>&1; make -C lib >>$@ 2>&1 && rm $@
+ $(MAKE) -C lib clean >$@ 2>&1; $(MAKE) -C lib >>$@ 2>&1 && rm $@
FEATURES_DUMP_FILE := $(FULL_O)/BUILD_TEST_FEATURE_DUMP
FEATURES_DUMP_FILE_STATIC := $(FULL_O)/BUILD_TEST_FEATURE_DUMP_STATIC
@@ -383,20 +387,22 @@ all: $(run) $(run_O) tarpkg make_kernelsrc make_kernelsrc_tools
@echo OK
@rm -f $(FEATURES_DUMP_FILE) $(FEATURES_DUMP_FILE_STATIC)
-out: $(run_O)
+out:
+ $(call clean)
+ @$(MAKE) -f tests/make $(run_O) PARALLEL_OPT= O_CLEAN=0 $(if $(findstring jobserver,$(MAKEFLAGS))$(findstring -j,$(MAKEFLAGS)),,$(if $(cores),-j$(cores)))
@echo OK
@rm -f $(FEATURES_DUMP_FILE) $(FEATURES_DUMP_FILE_STATIC)
ifeq ($(REUSE_FEATURES_DUMP),1)
$(FEATURES_DUMP_FILE):
$(call clean)
- @cmd="cd $(PERF) && make FEATURE_DUMP_COPY=$@ $(O_OPT) feature-dump"; \
+ @cmd="cd $(PERF) && $(MAKE) FEATURE_DUMP_COPY=$@ $(O_OPT) feature-dump"; \
echo "- $@: $$cmd" && echo $$cmd && \
( eval $$cmd ) > /dev/null 2>&1
$(FEATURES_DUMP_FILE_STATIC):
$(call clean)
- @cmd="cd $(PERF) && make FEATURE_DUMP_COPY=$@ $(O_OPT) LDFLAGS='-static' feature-dump"; \
+ @cmd="cd $(PERF) && $(MAKE) FEATURE_DUMP_COPY=$@ $(O_OPT) LDFLAGS='-static' feature-dump"; \
echo "- $@: $$cmd" && echo $$cmd && \
( eval $$cmd ) > /dev/null 2>&1
--
2.55.0.979.g7e5102b832-goog