On Wed, Oct 4, 2023 at 1:27 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > On Tue, Oct 03, 2023 at 05:17:49PM -0700, Andrii Nakryiko wrote: > > Add support for building selftests with -O2 level of optimization, which > > allows more compiler warnings detection (like lots of potentially > > uninitialized usage), but also is useful to have a faster-running test > > for some CPU-intensive tests. > > > > One can build optimized versions of libbpf and selftests by running: > > > > $ make RELEASE=1 > > > > There is a measurable speed up of about 10 seconds for me locally, > > though it's mostly capped by non-parallelized serial tests. User CPU > > time goes down by total 40 seconds, from 1m10s to 0m28s. > > > > Unoptimized build (-O0) > > ======================= > > Summary: 430/3544 PASSED, 25 SKIPPED, 4 FAILED > > > > real 1m59.937s > > user 1m10.877s > > sys 3m14.880s > > > > Optimized build (-O2) > > ===================== > > Summary: 425/3543 PASSED, 25 SKIPPED, 9 FAILED > > > > real 1m50.540s > > user 0m28.406s > > sys 3m13.198s > > hi, > I get following error when running selftest compiled with RELEASE=1 > > # ./test_progs -t attach_probe/manual-legacy > test_attach_probe:PASS:skel_open 0 nsec > test_attach_probe:PASS:skel_load 0 nsec > test_attach_probe:PASS:check_bss 0 nsec > test_attach_probe:PASS:uprobe_ref_ctr_cleanup 0 nsec > test_attach_probe_manual:PASS:skel_kprobe_manual_open_and_load 0 nsec > test_attach_probe_manual:PASS:uprobe_offset 0 nsec > test_attach_probe_manual:PASS:attach_kprobe 0 nsec > test_attach_probe_manual:PASS:attach_kretprobe 0 nsec > test_attach_probe_manual:PASS:attach_uprobe 0 nsec > test_attach_probe_manual:PASS:attach_uretprobe 0 nsec > libbpf: failed to add legacy uprobe event for /proc/self/exe:0x19020: -17 > libbpf: prog 'handle_uprobe_byname': failed to create uprobe '/proc/self/exe:0x19020' perf event: File exists > test_attach_probe_manual:FAIL:attach_uprobe_byname unexpected error: -17 > #8/2 attach_probe/manual-legacy:FAIL > #8 attach_probe:FAIL > > > it looks like -O2 can merge some of the trigger functions: > > [root@qemu bpf]# nm test_progs | grep trigger_func > 0000000000558f30 t autoattach_trigger_func.constprop.0 > 000000000041d240 t trigger_func > 0000000000419020 t trigger_func > 0000000000420e70 t trigger_func > 0000000000507aa0 t trigger_func > 0000000000419020 t trigger_func2 > 0000000000419020 t trigger_func3 > 0000000000419030 t trigger_func4 > [root@qemu bpf]# nm test_progs | grep 0000000000419020 > 0000000000419020 t trigger_func > 0000000000419020 t trigger_func2 > 0000000000419020 t trigger_func3 > > I got more tests fails, but I suspect it's all for similar > reason like above > yes, I didn't say that -O2 version passes all tests :) at least there are complicated USDT cases under -O2 which libbpf can't support (if I remember correctly, it was offset relative to global symbol case). But it's the first step. And once we have ability to build with RELEASE=1, we can add it as a separate test in CI and catch more of these uninitialized usage errors. Initially we can denylist tests that are broken due to -O2 and work to fix them. > jirka > > > > > > Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > > --- > > tools/testing/selftests/bpf/Makefile | 14 ++++++++------ > > 1 file changed, 8 insertions(+), 6 deletions(-) > > > > diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile > > index a25e262dbc69..55d1b1848e6c 100644 > > --- a/tools/testing/selftests/bpf/Makefile > > +++ b/tools/testing/selftests/bpf/Makefile > > @@ -27,7 +27,9 @@ endif > > BPF_GCC ?= $(shell command -v bpf-gcc;) > > SAN_CFLAGS ?= > > SAN_LDFLAGS ?= $(SAN_CFLAGS) > > -CFLAGS += -g -O0 -rdynamic \ > > +RELEASE ?= > > +OPT_FLAGS ?= $(if $(RELEASE),-O2,-O0) > > +CFLAGS += -g $(OPT_FLAGS) -rdynamic \ > > -Wall -Werror \ > > $(GENFLAGS) $(SAN_CFLAGS) \ > > -I$(CURDIR) -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR) \ > > @@ -241,7 +243,7 @@ $(OUTPUT)/runqslower: $(BPFOBJ) | $(DEFAULT_BPFTOOL) $(RUNQSLOWER_OUTPUT) > > BPFTOOL_OUTPUT=$(HOST_BUILD_DIR)/bpftool/ \ > > BPFOBJ_OUTPUT=$(BUILD_DIR)/libbpf \ > > BPFOBJ=$(BPFOBJ) BPF_INCLUDE=$(INCLUDE_DIR) \ > > - EXTRA_CFLAGS='-g -O0 $(SAN_CFLAGS)' \ > > + EXTRA_CFLAGS='-g $(OPT_FLAGS) $(SAN_CFLAGS)' \ > > EXTRA_LDFLAGS='$(SAN_LDFLAGS)' && \ > > cp $(RUNQSLOWER_OUTPUT)runqslower $@ > > > > @@ -279,7 +281,7 @@ $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \ > > $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool > > $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \ > > ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD="$(HOSTLD)" \ > > - EXTRA_CFLAGS='-g -O0' \ > > + EXTRA_CFLAGS='-g $(OPT_FLAGS)' \ > > OUTPUT=$(HOST_BUILD_DIR)/bpftool/ \ > > LIBBPF_OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \ > > LIBBPF_DESTDIR=$(HOST_SCRATCH_DIR)/ \ > > @@ -290,7 +292,7 @@ $(CROSS_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \ > > $(BPFOBJ) | $(BUILD_DIR)/bpftool > > $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \ > > ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) \ > > - EXTRA_CFLAGS='-g -O0' \ > > + EXTRA_CFLAGS='-g $(OPT_FLAGS)' \ > > OUTPUT=$(BUILD_DIR)/bpftool/ \ > > LIBBPF_OUTPUT=$(BUILD_DIR)/libbpf/ \ > > LIBBPF_DESTDIR=$(SCRATCH_DIR)/ \ > > @@ -313,7 +315,7 @@ $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \ > > $(APIDIR)/linux/bpf.h \ > > | $(BUILD_DIR)/libbpf > > $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(BUILD_DIR)/libbpf/ \ > > - EXTRA_CFLAGS='-g -O0 $(SAN_CFLAGS)' \ > > + EXTRA_CFLAGS='-g $(OPT_FLAGS) $(SAN_CFLAGS)' \ > > EXTRA_LDFLAGS='$(SAN_LDFLAGS)' \ > > DESTDIR=$(SCRATCH_DIR) prefix= all install_headers > > > > @@ -322,7 +324,7 @@ $(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \ > > $(APIDIR)/linux/bpf.h \ > > | $(HOST_BUILD_DIR)/libbpf > > $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) \ > > - EXTRA_CFLAGS='-g -O0' ARCH= CROSS_COMPILE= \ > > + EXTRA_CFLAGS='-g $(OPT_FLAGS)' ARCH= CROSS_COMPILE= \ > > OUTPUT=$(HOST_BUILD_DIR)/libbpf/ \ > > CC="$(HOSTCC)" LD="$(HOSTLD)" \ > > DESTDIR=$(HOST_SCRATCH_DIR)/ prefix= all install_headers > > -- > > 2.34.1 > > > >
