On Fri, Jul 19, 2024 at 11:18:16AM -0700, Andrii Nakryiko wrote: > On Thu, Jul 18, 2024 at 3:57 PM Ihor Solodrai <ihor.solodrai@xxxxx> wrote: > > > > Make use of -M compiler options when building .test.o objects to > > generate .d files and avoid re-building all tests every time. > > > > Previously, if a single test bpf program under selftests/bpf/progs/*.c > > has changed, make would rebuild all the *.bpf.o, *.skel.h and *.test.o > > objects, which is a lot of unnecessary work. > > > > A typical dependency chain is: > > progs/x.c -> x.bpf.o -> x.skel.h -> x.test.o -> trunner_binary > > > > However for many tests it's not a 1:1 mapping by name, and so far > > %.test.o have been simply dependent on all %.skel.h files, and > > %.skel.h files on all %.bpf.o objects. > > > > Avoid full rebuilds by instructing the compiler (via -MMD) to > > produce *.d files with real dependencies, and appropriately including > > them. Exploit make feature that rebuilds included makefiles if they > > were changed by setting %.test.d as prerequisite for %.test.o files. > > > > A couple of examples of compilation time speedup (after the first > > clean build): > > > > $ touch progs/verifier_and.c && time make -j8 > > Before: real 0m16.651s > > After: real 0m2.245s > > $ touch progs/read_vsyscall.c && time make -j8 > > Before: real 0m15.743s > > After: real 0m1.575s > > > > A drawback of this change is that now there is an overhead due to make > > processing lots of .d files, which potentially may slow down unrelated > > targets. However a time to make all from scratch hasn't changed > > significantly: > > > > $ make clean && time make -j8 > > Before: real 1m31.148s > > After: real 1m30.309s > > > > Suggested-by: Eduard Zingerman <eddyz87@xxxxxxxxx> > > Signed-off-by: Ihor Solodrai <ihor.solodrai@xxxxx> > > > > --- > > v3 -> v4: Make $(TRUNNER_BPF_OBJS) order only prereq of trunner binary > > v2 -> v3: Restore dependency on $(TRUNNER_BPF_OBJS) > > v1 -> v2: Make %.test.d prerequisite order only > > --- > > tools/testing/selftests/bpf/.gitignore | 1 + > > tools/testing/selftests/bpf/Makefile | 44 +++++++++++++++++++------- > > 2 files changed, 34 insertions(+), 11 deletions(-) > > > > It seems to behave correctly, but it reports wrong flavor when > building .bpf.o, e.g.,: > Hi Andrii, This is actually an old, confusing bug unrelated to the current (very nice) improvements. I have a fix as part of a larger series targeting libc portability and MIPS support which I'll post shortly. Or I can send separately if you like? Thanks, Tony > $ touch progs/test_vmlinux.c > $ make -j90 > CLNG-BPF [test_maps] test_vmlinux.bpf.o > CLNG-BPF [test_maps] test_vmlinux.bpf.o > CLNG-BPF [test_maps] test_vmlinux.bpf.o > GEN-SKEL [test_progs] test_vmlinux.skel.h > GEN-SKEL [test_progs-cpuv4] test_vmlinux.skel.h > GEN-SKEL [test_progs-no_alu32] test_vmlinux.skel.h > TEST-OBJ [test_progs] vmlinux.test.o > TEST-OBJ [test_progs-no_alu32] vmlinux.test.o > EXT-COPY [test_progs-no_alu32] urandom_read bpf_testmod.ko > bpf_test_no_cfi.ko liburandom_read.so xdp_synproxy sign-file > uprobe_multi ima_setup.sh verify_sig_setup.sh > btf_dump_test_case_bitfields.c btf_dump_test_case_multidim.c > btf_dump_test_case_namespacing.c btf_dump_test_case_ordering.c > btf_dump_test_case_packing.c btf_dump_test_case_padding.c > btf_dump_test_case_syntax.c > TEST-OBJ [test_progs-cpuv4] vmlinux.test.o > EXT-COPY [test_progs-cpuv4] urandom_read bpf_testmod.ko > bpf_test_no_cfi.ko liburandom_read.so xdp_synproxy sign-file > uprobe_multi ima_setup.sh verify_sig_setup.sh > btf_dump_test_case_bitfields.c btf_dump_test_case_multidim.c > btf_dump_test_case_namespacing.c btf_dump_test_case_ordering.c > btf_dump_test_case_packing.c btf_dump_test_case_padding.c > btf_dump_test_case_syntax.c > make[1]: Nothing to be done for 'docs'. > BINARY test_progs > BINARY test_progs-no_alu32 > BINARY test_progs-cpuv4 > $ ls -la test_vmlinux.bpf.o no_alu32/test_vmlinux.bpf.o cpuv4/test_vmlinux.bpf.o > -rw-r--r-- 1 andriin users 21344 Jul 19 11:08 cpuv4/test_vmlinux.bpf.o > -rw-r--r-- 1 andriin users 21408 Jul 19 11:08 no_alu32/test_vmlinux.bpf.o > -rw-r--r-- 1 andriin users 21408 Jul 19 11:08 test_vmlinux.bpf.o > > > Note [test_maps] for all three variants (I expected > test_maps/test_progs + no_alu32 + cpuv4, just like we see for skel.h). > Can you please double check what's going on? Looking at timestamps it > seems like they are actually regenerated, though. > > > BTW, if you get a chance, see if you can avoid unnecessary EXT-COPY as > well (probably a bit smarter rule dependency should be set up, e.g., > phony target that then depends on actual files or something like > that). > > Regardless, this is a massive improvement and seems to work correctly, > so I've applied this and will wait for follow ups. Thanks a lot! > > BTW, are you planning to look into vmlinux.h optimization as well? > > > diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore > > index 5025401323af..4e4aae8aa7ec 100644 > > --- a/tools/testing/selftests/bpf/.gitignore > > +++ b/tools/testing/selftests/bpf/.gitignore > > @@ -31,6 +31,7 @@ test_tcp_check_syncookie_user > > test_sysctl > > xdping > > test_cpp > > +*.d > > *.subskel.h > > *.skel.h > > *.lskel.h > > [...]
