2d7460482d
This commit refactors kernel and arch headers to establish a boundary
between private and public interface headers.
The refactoring strategy used in this commit is detailed in the issue
This commit introduces the following major changes:
1. Establish a clear boundary between private and public headers by
removing "kernel/include" and "arch/*/include" from the global
include paths. Ideally, only kernel/ and arch/*/ source files should
reference the headers in these directories. If these headers must be
used by a component, these include paths shall be manually added to
the CMakeLists.txt file of the component. This is intended to
discourage applications from including private kernel and arch
headers either knowingly and unknowingly.
- kernel/include/ (PRIVATE)
This directory contains the private headers that provide private
kernel definitions which should not be visible outside the kernel
and arch source code. All public kernel definitions must be added
to an appropriate header located under include/.
- arch/*/include/ (PRIVATE)
This directory contains the private headers that provide private
architecture-specific definitions which should not be visible
outside the arch and kernel source code. All public architecture-
specific definitions must be added to an appropriate header located
under include/arch/*/.
- include/ AND include/sys/ (PUBLIC)
This directory contains the public headers that provide public
kernel definitions which can be referenced by both kernel and
application code.
- include/arch/*/ (PUBLIC)
This directory contains the public headers that provide public
architecture-specific definitions which can be referenced by both
kernel and application code.
2. Split arch_interface.h into "kernel-to-arch interface" and "public
arch interface" divisions.
- kernel/include/kernel_arch_interface.h
* provides private "kernel-to-arch interface" definition.
* includes arch/*/include/kernel_arch_func.h to ensure that the
interface function implementations are always available.
* includes sys/arch_interface.h so that public arch interface
definitions are automatically included when including this file.
- arch/*/include/kernel_arch_func.h
* provides architecture-specific "kernel-to-arch interface"
implementation.
* only the functions that will be used in kernel and arch source
files are defined here.
- include/sys/arch_interface.h
* provides "public arch interface" definition.
* includes include/arch/arch_inlines.h to ensure that the
architecture-specific public inline interface function
implementations are always available.
- include/arch/arch_inlines.h
* includes architecture-specific arch_inlines.h in
include/arch/*/arch_inline.h.
- include/arch/*/arch_inline.h
* provides architecture-specific "public arch interface" inline
function implementation.
* supersedes include/sys/arch_inline.h.
3. Refactor kernel and the existing architecture implementations.
- Remove circular dependency of kernel and arch headers. The
following general rules should be observed:
* Never include any private headers from public headers
* Never include kernel_internal.h in kernel_arch_data.h
* Always include kernel_arch_data.h from kernel_arch_func.h
* Never include kernel.h from kernel_struct.h either directly or
indirectly. Only add the kernel structures that must be referenced
from public arch headers in this file.
- Relocate syscall_handler.h to include/ so it can be used in the
public code. This is necessary because many user-mode public codes
reference the functions defined in this header.
- Relocate kernel_arch_thread.h to include/arch/*/thread.h. This is
necessary to provide architecture-specific thread definition for
'struct k_thread' in kernel.h.
- Remove any private header dependencies from public headers using
the following methods:
* If dependency is not required, simply omit
* If dependency is required,
- Relocate a portion of the required dependencies from the
private header to an appropriate public header OR
- Relocate the required private header to make it public.
This commit supersedes #20047, addresses #19666, and fixes #3056.
Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
|
||
|---|---|---|
| .. | ||
| src | ||
| CMakeLists.txt | ||
| README.rst | ||
| prj.conf | ||
| testcase.yaml | ||
README.rst
Scheduler Microbenchmark
########################
This is a scheduler microbenchmark, designed to measure minimum
latencies (not scaling performance) of specific low level scheduling
primitives independent of overhead from application or API
abstractions. It works very simply: a main thread creates a "partner"
thread at a higher priority, the partner then sleeps using
_pend_curr_irqlock(). From this initial state:
1. The main thread calls _unpend_first_thread()
2. The main thread calls _ready_thread()
3. The main thread calls k_yield()
(the kernel switches to the partner thread)
4. The partner thread then runs and calls _pend_curr_irqlock() again
(the kernel switches to the main thread)
5. The main thread returns from k_yield()
It then iterates this many times, reporting timestamp latencies
between each numbered step and for the whole cycle, and a running
average for all cycles run.
Note that because this involves no timer interaction (except, on some
architectures, k_cycle_get_32()), it works correctly when run in QEMU
using the -icount argument, which can produce 100% deterministic
behavior (not cycle-exact hardware simulation, but exactly N
instructions per simulated nanosecond). You can enable this using an
environment variable (set at cmake time -- it's not enough to do this
for the subsequent make/ninja invocation, cmake needs to see the
variable itself):
export QEMU_EXTRA_FLAGS="-icount shift=0,align=off,sleep=off"