From: Jiri Olsa <olsajiri@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Jiri Olsa <olsajiri@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
martin.lau@kernel.org, kernel-team@meta.com
Subject: Re: [PATCH bpf-next 2/3] selftests/bpf: support building selftests in optimized -O2 mode
Date: Thu, 5 Oct 2023 09:19:26 +0200 [thread overview]
Message-ID: <ZR5jfh939hHLtnED@krava> (raw)
In-Reply-To: <CAEf4Bzag+5_r05t7p2N-XiWykT51U5x4ov7YSa0NGVJrGpo6UQ@mail.gmail.com>
On Wed, Oct 04, 2023 at 10:21:12AM -0700, Andrii Nakryiko wrote:
> On Wed, Oct 4, 2023 at 1:27 AM Jiri Olsa <olsajiri@gmail.com> 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.
I see ;-) sounds good
Acked-by: Jiri Olsa <jolsa@kernel.org>
jirka
>
> > jirka
> >
> >
> > >
> > > Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> > > ---
> > > 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
> > >
> > >
next prev parent reply other threads:[~2023-10-05 7:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-04 0:17 [PATCH bpf-next 1/3] selftests/bpf: fix compiler warnings reported in -O2 mode Andrii Nakryiko
2023-10-04 0:17 ` [PATCH bpf-next 2/3] selftests/bpf: support building selftests in optimized " Andrii Nakryiko
2023-10-04 8:27 ` Jiri Olsa
2023-10-04 17:21 ` Andrii Nakryiko
2023-10-05 7:19 ` Jiri Olsa [this message]
2023-10-05 9:04 ` Alan Maguire
2023-10-06 17:55 ` Andrii Nakryiko
2023-10-06 17:56 ` Andrii Nakryiko
2023-10-04 0:17 ` [PATCH bpf-next 3/3] selftests/bpf: don't truncate #test/subtest field Andrii Nakryiko
2023-10-05 7:21 ` Jiri Olsa
2023-10-05 7:21 ` [PATCH bpf-next 1/3] selftests/bpf: fix compiler warnings reported in -O2 mode Jiri Olsa
2023-10-06 18:20 ` patchwork-bot+netdevbpf
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