Re: [PATCH bpf-next 2/3] tools: runqslower: build and use lightweight bootstrap version of bpftool

[Pu Lehui]

On 2022/7/14 2:52, Andrii Nakryiko wrote:
> On Mon, Jul 11, 2022 at 7:37 PM Pu Lehui <pulehui@xxxxxxxxxx> wrote:
> > tools/runqslower use bpftool for vmlinux.h, skeleton, and static linking
> > only. So we can use lightweight bootstrap version of bpftool to handle
> > these, and it will be faster.
> >
> > Signed-off-by: Pu Lehui <pulehui@xxxxxxxxxx>
> > Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> > ---
> >   tools/bpf/runqslower/Makefile | 10 ++++++++--
> >   1 file changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/bpf/runqslower/Makefile b/tools/bpf/runqslower/Makefile
> > index da6de16a3dfb..8900c74f29e2 100644
> > --- a/tools/bpf/runqslower/Makefile
> > +++ b/tools/bpf/runqslower/Makefile
> > @@ -4,7 +4,7 @@ include ../../scripts/Makefile.include
> >   OUTPUT ?= $(abspath .output)/
> >
> >   BPFTOOL_OUTPUT := $(OUTPUT)bpftool/
> > -DEFAULT_BPFTOOL := $(BPFTOOL_OUTPUT)bpftool
> > +DEFAULT_BPFTOOL := $(BPFTOOL_OUTPUT)bootstrap/bpftool
> >   BPFTOOL ?= $(DEFAULT_BPFTOOL)
> >   LIBBPF_SRC := $(abspath ../../lib/bpf)
> >   BPFOBJ_OUTPUT := $(OUTPUT)libbpf/
> > @@ -86,6 +86,12 @@ $(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(BPFOBJ_OU
> >          $(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(BPFOBJ_OUTPUT) \
> >                      DESTDIR=$(BPFOBJ_OUTPUT) prefix= $(abspath $@) install_headers
> >
> > +ifeq ($(CROSS_COMPILE),)
> >   $(DEFAULT_BPFTOOL): $(BPFOBJ) | $(BPFTOOL_OUTPUT)
> >          $(Q)$(MAKE) $(submake_extras) -C ../bpftool OUTPUT=$(BPFTOOL_OUTPUT)   \
> > -                   ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD)
> > +                   LIBBPF_BOOTSTRAP_OUTPUT=$(BPFOBJ_OUTPUT)                   \
> > +                   LIBBPF_BOOTSTRAP_DESTDIR=$(BPF_DESTDIR) bootstrap
> > +else
> > +$(DEFAULT_BPFTOOL): | $(BPFTOOL_OUTPUT)
> > +       $(Q)$(MAKE) $(submake_extras) -C ../bpftool OUTPUT=$(BPFTOOL_OUTPUT) bootstrap
> > +endif
>
> Same comment as on the other patch, this CROSS_COMPILE if/else seems a
> bit fragile, let's keep only the second cleaner part, maybe?

I will make it simple.

> > --
> > 2.25.1
> .