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authorIan Rogers <irogers@google.com>2024-10-28 12:36:19 -0700
committerNamhyung Kim <namhyung@kernel.org>2024-11-04 11:32:35 -0800
commit13e17c9ff49119aa2826dbf1e130f34d4d7a55d9 (patch)
treefe05f24833abadf657695cdf9a6b69504a03ad41
parentaa5c90601b531323f82ceb02b41a66974153b76f (diff)
downloadlwn-13e17c9ff49119aa2826dbf1e130f34d4d7a55d9.tar.gz
lwn-13e17c9ff49119aa2826dbf1e130f34d4d7a55d9.zip
perf build: Make libunwind opt-in rather than opt-out
Having multiple unwinding libraries makes the perf code harder to understand and we have unused/untested code paths. Perf made BPF support an opt-out rather than opt-in feature. As libbpf has a libelf dependency, elfutils that provides libelf will also provide libdw. When libdw is present perf will use libdw unwinding rather than libunwind unwinding even if libunwind support is compiled in. Rather than have libunwind built into perf and never used, explicitly disable the support and make it opt-in. Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Link: https://lore.kernel.org/r/20241028193619.247727-1-irogers@google.com Closes: https://lore.kernel.org/linux-perf-users/CAP-5=fUXkp-d7gkzX4eF+nbjb2978dZsiHZ9abGHN=BN1qAcbg@mail.gmail.com/ Signed-off-by: Namhyung Kim <namhyung@kernel.org>
-rw-r--r--tools/perf/Makefile.config4
-rw-r--r--tools/perf/Makefile.perf2
-rw-r--r--tools/perf/tests/make6
3 files changed, 8 insertions, 4 deletions
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 8da6d91b7ad5..e68f0be259a1 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -95,6 +95,10 @@ ifneq ($(SRCARCH),$(filter $(SRCARCH),x86 arm arm64 powerpc s390 csky riscv loon
NO_LIBDW_DWARF_UNWIND := 1
endif
+ifneq ($(LIBUNWIND),1)
+ NO_LIBUNWIND := 1
+endif
+
ifeq ($(LIBUNWIND_LIBS),)
NO_LIBUNWIND := 1
endif
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index b4dee7c20ed1..d74241a15131 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -52,7 +52,7 @@ include ../scripts/utilities.mak
#
# Define NO_LIBELF if you do not want libelf dependency (e.g. cross-builds)
#
-# Define NO_LIBUNWIND if you do not want libunwind dependency for dwarf
+# Define LIBUNWIND if you do not want libunwind dependency for dwarf
# backtrace post unwind.
#
# Define NO_BACKTRACE if you do not want stack backtrace debug feature
diff --git a/tools/perf/tests/make b/tools/perf/tests/make
index a5040772043f..a7fcbd589752 100644
--- a/tools/perf/tests/make
+++ b/tools/perf/tests/make
@@ -81,7 +81,7 @@ make_no_gtk2 := NO_GTK2=1
make_no_ui := NO_SLANG=1 NO_GTK2=1
make_no_demangle := NO_DEMANGLE=1
make_no_libelf := NO_LIBELF=1
-make_no_libunwind := NO_LIBUNWIND=1
+make_libunwind := LIBUNWIND=1
make_no_libdw_dwarf_unwind := NO_LIBDW_DWARF_UNWIND=1
make_no_backtrace := NO_BACKTRACE=1
make_no_libcapstone := NO_CAPSTONE=1
@@ -121,7 +121,7 @@ make_static := LDFLAGS=-static NO_PERF_READ_VDSO32=1 NO_PERF_READ_VDSOX3
# all the NO_* variable combined
make_minimal := NO_LIBPERL=1 NO_LIBPYTHON=1 NO_GTK2=1
-make_minimal += NO_DEMANGLE=1 NO_LIBELF=1 NO_LIBUNWIND=1 NO_BACKTRACE=1
+make_minimal += NO_DEMANGLE=1 NO_LIBELF=1 NO_BACKTRACE=1
make_minimal += NO_LIBNUMA=1 NO_LIBAUDIT=1 NO_LIBBIONIC=1
make_minimal += NO_LIBDW_DWARF_UNWIND=1 NO_AUXTRACE=1 NO_LIBBPF=1
make_minimal += NO_LIBCRYPTO=1 NO_SDT=1 NO_JVMTI=1 NO_LIBZSTD=1
@@ -153,7 +153,7 @@ run += make_no_gtk2
run += make_no_ui
run += make_no_demangle
run += make_no_libelf
-run += make_no_libunwind
+run += make_libunwind
run += make_no_libdw_dwarf_unwind
run += make_no_backtrace
run += make_no_libcapstone