Re: [PATCH bpf-next v2 5/6] tools/runqslower: Enable out-of-tree build

[Jean-Philippe Brucker <jean-philippe@linaro.org>]

On Mon, Nov 09, 2020 at 12:23:28PM -0800, Andrii Nakryiko wrote:
> On Mon, Nov 9, 2020 at 3:11 AM Jean-Philippe Brucker
> <jean-philippe@linaro.org> wrote:
> >
> > Enable out-of-tree build for runqslower. Only set OUTPUT=.output if it
> > wasn't already set by the user.
> >
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > ---
> >  tools/bpf/runqslower/Makefile | 45 +++++++++++++++++++++++------------
> >  1 file changed, 30 insertions(+), 15 deletions(-)
> >
> > diff --git a/tools/bpf/runqslower/Makefile b/tools/bpf/runqslower/Makefile
> > index bcc4a7396713..861f4dcde960 100644
> > --- a/tools/bpf/runqslower/Makefile
> > +++ b/tools/bpf/runqslower/Makefile
> > @@ -1,15 +1,20 @@
> >  # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
> >  include ../../scripts/Makefile.include
> >
> > -OUTPUT := .output
> > +ifeq ($(OUTPUT),)
> > +  OUTPUT = $(abspath .output)/
> > +endif
> 
> OUTPUT ?= .. didn't work?

Yes it should, I'll change it. The difference is when make is invoked with
OUTPUT explicitly set to "", then ?= wouldn't override it. But I didn't
see any external Makefile passing OUTPUT= to this one, and the user-facing
option is O=

> 
> > +
> >  CLANG ?= clang
> >  LLC ?= llc
> >  LLVM_STRIP ?= llvm-strip
> > -DEFAULT_BPFTOOL := $(OUTPUT)/sbin/bpftool
> > +BPFTOOL_OUTPUT := $(OUTPUT)bpftool/
> > +DEFAULT_BPFTOOL := $(BPFTOOL_OUTPUT)bpftool
> >  BPFTOOL ?= $(DEFAULT_BPFTOOL)
> >  LIBBPF_SRC := $(abspath ../../lib/bpf)
> > -BPFOBJ := $(OUTPUT)/libbpf.a
> > -BPF_INCLUDE := $(OUTPUT)
> > +BPFOBJ_OUTPUT := $(OUTPUT)libbpf/
> > +BPFOBJ := $(BPFOBJ_OUTPUT)libbpf.a
> > +BPF_INCLUDE := $(BPFOBJ_OUTPUT)
> >  INCLUDES := -I$(OUTPUT) -I$(BPF_INCLUDE) -I$(abspath ../../lib)        \
> >         -I$(abspath ../../include/uapi)
> >  CFLAGS := -g -Wall
> > @@ -20,7 +25,6 @@ VMLINUX_BTF_PATHS := /sys/kernel/btf/vmlinux /boot/vmlinux-$(KERNEL_REL)
> >  VMLINUX_BTF_PATH := $(or $(VMLINUX_BTF),$(firstword                           \
> >                                           $(wildcard $(VMLINUX_BTF_PATHS))))
> >
> > -abs_out := $(abspath $(OUTPUT))
> >  ifeq ($(V),1)
> >  Q =
> >  else
> > @@ -36,9 +40,13 @@ all: runqslower
> >
> >  runqslower: $(OUTPUT)/runqslower
> >
> > -clean:
> > +clean: $(DEFAULT_BPFTOOL)-clean $(BPFOBJ)-clean
> 
> why separate targets for $(DEFAULT_BPFTOOL)-clean and $(BPFOBJ)-clean?
> Are they intended to be called separately? I don't think
> parallelization is that important for the clean up. Let's just keep
> all the cleaning in one place, not spreading it across Makefile?

Ok

Thanks,
Jean