Make it possible to "finish" with fewer bytes than what was "claimed".
This was possible before on the get side, but the put side was
cummulative wrt finish. The revamp made it cummulative on both sides.
Turns out that existing users rely on the opposite behavior which is
more logical and useful. So make both sides that way.
Adjust documentation, test case and users accordingly.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
The item mode is really a specialization of the byte mode. And in-tree
usage shows the byte mode is prominent. It feels more natural if the
byte mode is presented first with the item mode second. Swap the code
and documentation order accordingly. No code change.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
The core ring buffer code presumes a 32-bit wrap-around behavior when its
head and tail indices cross the maximum value range. Make sure this is
covered by the test suite, for both 32- and 64-bit targets.
While at it, reduce stack requirement of the modified test.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
This code is rather hairy. When I look at it I don't like the way it
stares back at me.
First, the rewind business looks fishy. It has to die.
And we don't have to rely on modulus either. Not even for non-power-of-2
buffers. Let's kill that distinction too and make all sizes always
"high performance".
The code is now entirely relying only on simple ALU operations (add,
sub and compare).
The key assumption: 32-bit values do wrap around after max range has
been reached. No saturation. All architectures supported by Zephyr
do that.
Some stats:
lib/os/ring_buffer.c: 62 insertions(+), 124 deletions(-)
ring_buffer.c.obj before after diff
----------------------------------------------
frdm_k64f 1224 1136 -88
m2gl025_miv 2485 2079 -406
mps2_an385 1228 1132 -96
mps2_an521 1228 1132 -96
native_posix 1546 1496 -50
native_posix_64 1598 1595 -3
nsim_hs_mpuv6 1252 1192 -60
nsim_hs_smp 1252 1192 -60
nsim_sem 1252 1192 -60
qemu_arc_em 1324 1192 -132
qemu_arc_hs6x 1824 1620 -204
qemu_arc_hs 1252 1192 -60
qemu_cortex_a53_smp 2154 1888 -266
qemu_cortex_a53 2154 1888 -266
qemu_cortex_a9 1938 1792 -146
Before (qemu_cortex_a53):
START - test_ringbuffer_performance
1 byte put-get, avg cycles: 52
4 byte put-get, avg cycles: 47
1 byte put claim-finish, avg cycles: 39
5 byte put claim-finish, avg cycles: 41
5 byte get claim-finish, avg cycles: 52
PASS - test_ringbuffer_performance in 0.8 seconds
After (qemu_cortex_a53):
START - test_ringbuffer_performance
1 byte put-get, avg cycles: 34
4 byte put-get, avg cycles: 41
1 byte put claim-finish, avg cycles: 27
5 byte put claim-finish, avg cycles: 29
5 byte get claim-finish, avg cycles: 29
PASS - test_ringbuffer_performance in 0.4 seconds
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Conceptually, ring_buf_item_put() and ring_buf_item_get() are specialized
versions of ring_buf_put() and ring_buf_get(). Make it so to rationalize
the code to open the way for more optimizations.
This means we need specialized wrappers on top of ring_buf_init()
accordingly, given that the core machinery is now common and byte based.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
The ring buffer's static declarations now declare the
ring buffer's data as __noinit, to avoid unnecessary
initialization of the buffer.
Signed-off-by: Yonatan Schachter <yonatan.schachter@gmail.com>
Ring buffer claims that no synchronization is needed
when there is a single producer and single consumer.
However, recent changes have broken that promise since
indexes rewind mechanism was modifing head and tail
when consuming. Patch fixes that by spliting rewinding
of indexes so that producer rewinds tail only and
consumer rewinds head.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Description was falsely static that macros statically creates
the ring buffer objects. Clarify description since variables
are not static.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Add ring_buf_size_get() to get the number of bytes currently available
in the ring buffer.
Add ring_buf_peek() to read data from the head of a ring buffer without
removal.
Fixes#37145
Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>
Move out of misc/ and put in own folder and add the grouping to doxygen
to be able to reference the doxygen docs into RST.
Move each item into their own file to reduce clutter and to make it
less crowded in one single page.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Allow NULL data buffers to be provided to `ring_buf_get` and
`ring_buf_item_get`, in which case data will be discarded instead of
copied out to the user.
Fixes#33488.
Signed-off-by: Jordan Yates <jordan.yates@data61.csiro.au>
Removing line exceeding warnings which appeared after u32_t -> uint32_t
converstion.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Previously, ring buffer had capacity of provided buffer size - 1. This
trick was used to distinguish between empty and full states. It had one
drawback: ring buffer could not be used as a pool of equal sized buffers
(using ring_buf_put_claim and ring_buf_get_claim).
Reworked internals to use non wrapping head and tail. Since they are
non wrapping, there is no issue with distinguishing between empty and
full. Since this appraoch would be vulnerable to wrapping on 32 bit
boundary, added a mechanism which periodically reduces all indexes to
avoid 32 bit wrapping.
After this rework, buffer has one byte more capacity. Simple test shows
slight performance improvement.
Updated tests to reflect increased capacity and added test to check if
it is possible to continuesly allocated 2 buffers of half ring buffer
size.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Remove SYS_RING_BUF_DECLARE_POW2 and SYS_RING_BUF_DECLARE_SIZE as they
have been marked deprecated for at least 2 releases.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Both operands of an operator in the arithmetic conversions
performed shall have the same essential type category.
Changes are related to converting the integer constants to the
unsigned integer constants
Signed-off-by: Aastha Grover <aastha.grover@intel.com>
move misc/util.h to sys/util.h and
create a shim for backward-compatibility.
No functional changes to the headers.
A warning in the shim can be controlled with CONFIG_COMPAT_INCLUDES.
Related to #16539
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
move ring_buffer.h to sys/ring_buffer.h and
create a shim for backward-compatibility.
No functional changes to the headers.
A warning in the shim can be controlled with CONFIG_COMPAT_INCLUDES.
Related to #16539
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
