mirror of
https://github.com/netdata/libbpf.git
synced 2026-03-22 09:19:06 +08:00
59c979cadc
The full memory barrier in the XDP socket rings on the consumer side between the load of the data and the store of the consumer ring is there to protect the store from being executed before the load of the data. If this was allowed to happen, the producer might overwrite the data field with a new entry before the consumer got the chance to read it. On x86, stores are guaranteed not to be reordered with older loads, so it does not need a full memory barrier here. A compile time barrier would be enough. This patch introdcues a new primitive in libbpf_util.h that implements a new barrier type (libbpf_smp_rwmb) hindering stores to be reordered with older loads. It is then used in the XDP socket ring access code in libbpf to improve performance. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This is a mirror of bpf-next linux tree
(https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next)
bpf-next/tools/lib/bpf directory plus its supporting header files.
The following files will by sync'ed with bpf-next repo:
src/ <-> bpf-next/tools/lib/bpf/
include/uapi/linux/bpf_common.h <-> bpf-next/tools/include/uapi/linux/bpf_common.h
include/uapi/linux/bpf.h <-> bpf-next/tools/include/uapi/linux/bpf.h
include/uapi/linux/btf.h <-> bpf-next/tools/include/uapi/linux/btf.h
include/uapi/linux/if_link.h <-> bpf-next/tools/include/uapi/linux/if_link.h
include/uapi/linux/if_xdp.h <-> bpf-next/tools/include/uapi/linux/if_xdp.h
include/uapi/linux/netlink.h <-> bpf-next/tools/include/uapi/linux/netlink.h
include/tools/libc_compat.h <-> bpf-next/tools/include/tools/libc_compat.h
Other header files at this repo (include/linux/*.h) are reduced versions of
their counterpart files at bpf-next/tools/include/linux/*.h to make compilation
successful.
Build
=====
libelf is an internal dependency of libbpf and thus it is required to link
against and must be installed on the system for applications to work.
pkg-config is used by default to find libelf, and the program called can be
overridden with PKG_CONFIG.
If using pkg-config at build time is not desired, it can be disabled by setting
NO_PKG_CONFIG=1 when calling make.
To build both static libbpf.a and shared libbpf.so:
cd src
make
To build only static libbpf.a library in directory
build/ and install them together with libbpf headers in a staging directory
root/:
cd src
mkdir build root
BUILD_STATIC_ONLY=y OBJDIR=build DESTDIR=root make install
To build both static libbpf.a and shared libbpf.so against a custom libelf
dependency installed in /build/root/ and install them together with libbpf
headers in a build directory /build/root/:
cd src
PKG_CONFIG_PATH=/build/root/lib64/pkgconfig DESTDIR=/build/root make install
To integrate libbpf into a project which uses Meson building system define
[wrap-git] file in `subprojects` folder.
To add libbpf dependency to the parent parent project, e.g. for
libbpf_static_dep:
libbpf_obj = subproject('libbpf', required : true)
libbpf_static_dep = libbpf_proj.get_variable('libbpf_static_dep')
To validate changes to meson.build
python3 meson.py build
ninja -C build/
To install headers, libs and pkgconfig
cd build
ninja install