* scx-lavd: preemption of a lower-priority task using kick cpu
When a task is enqueued to the global queue, the scheduler checks if
there is a lower priority task than the enqueued task. If so, it kicks
out the lower-priority task, hoping the newly enqueued task or another
higher-priority task runs on the kicked CPU. Kicking another CPU is
expensive as an IPI is involved, so the scheduler judiciously kicks the
CPU when its benefit (i.e., priority gap) is clear enough.
Signed-off-by: Changwoo Min <changwoo@igalia.com>
The build system included linux/btf.h from system even there is one in
libbpf. Adding libbpf/include/uapi to libbpf_local_h, the build
system will include linux/btf.h provided by libbpf.
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
The scx_rusty scheduler does not support hotplug, and expects a static
host topology throughout its runtime. Though the kernel does have
support for detecting hotplug events, we currently don't detect this in
the kernel, nor surface it to user space when it happens. Now that we
have scx_bpf_exit(), we can gracefully exit the kernel in the event of a
hotplug, and communicate to user space that it should restart the
scheduler.
This patch adds that support to scx_rusty. Note that this assumes that
we're running on a recent enough kernel that has scx_bpf_exit(). If it
doesn't, then we instead just error out of the kernel scheduler and exit
the application.
Signed-off-by: David Vernet <void@manifault.com>
Newer kernels also support exiting gracefully with an exit code. Let's
update the UserExitInfo struct to also read and export this value.
Signed-off-by: David Vernet <void@manifault.com>
scx_rustland_core needs to ship both a binary part and a source code
part, which will be used to build schedulers based on it.
To effectively publish the scx_rustland_core crate on crates.io we need
to properly separate the source code assets from the crate's main source
code.
To achieve this, move the assets into a separate directory and declare
them inside a [lib] section in Cargo.toml.
This allows to publish the crate on crates.io, providing also a clear
separation between source code and assets.
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Now that libbpf-rs 0.23 has been officially released with the new
consume_raw() API (https://github.com/libbpf/libbpf-rs/pull/680) we can
re-introduce the change in rustland-core that allows to use this API to
improve the quality of the code and make it slightly more efficient when
consuming tasks from BPF to user-space.
Fixes: bd2c18a ("Revert "scx_rustland_core: use new consume_raw() libbpf-rs API"")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
During the build meson attempts to distribute the workload of multiple
sub-projects across all available CPUs and parallelize each build within
those projects, resulting in an NxN task generation.
This process could potentially overload the CI systems, leading to
potential failures (see for example issue #202).
To mitigate this, always use --jobs=1 during the CI run, which
serializes the build of sub-projects and restricts the level of
parallelization to N.
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
If we try to cross-build scx on builders with older versions of system's
linux headers (such as those provided by linux-libc-headers in older
releases of Ubuntu), we may hit build failures, due to the different
kernel ABI, such as:
error: invalid use of undefined type ‘struct btf_enum64’
To address this, introduce a new build option called "kernel_headers"
that allows to specify a custom path for the kernel headers required
during the build process.
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Build fails with sccache.
- Update meson-scripts/build_bpftool to support sccache. Unfortunately, this
isn't enough.
- Update README to warn about sccache and add the instruction to disable it
for buliding scx.
- Also add ⚠️ to make boot loader update step more prominent in arch
installation instruction.
Synchronize stragglers.
- Bug fix in __COMPAT_read_enum().
- A cosmetic difference in scx_qmap.bpf.c.
- Stray 'p' when calling getopt() in scx_simple.c.
After this the kernel tree and scx repo are in sync.
