Some thread fields were 32-bit wide, when they are not even close to
using that full range of values. They are instead changed to 8-bit fields.
- prio can fit in one byte, limiting the priorities range to -128 to 127
- recursive scheduler locking can be limited to 255; a rollover results
most probably from a logic error
- flags are split into execution flags and thread states; 8 bits is
enough for each of them currently, with at worst two states and four
flags to spare (on x86, on other archs, there are six flags to spare)
Doing this saves 8 bytes per stack. It also sets up an incoming
enhancement when checking if the current thread is preemptible on
interrupt exit.
Change-Id: Ieb5321a5b99f99173b0605dd4a193c3bc7ddabf4
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
This will allow for an enhancement when checking if the thread is
preemptible when exiting an interrupt.
Change-Id: If93ccd1916eacb5e02a4d15b259fb74f9800d6f4
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
Not needed, since only the thread itself can modifiy its own
sched_locked count.
Change-Id: I3d3d8be548d2b24ca14f51637cc58bda66f8b9ee
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
Some tick frequencies lend themselves to optimized conversions from ms
to ticks and vice-versa.
- 1000Hz which does not need any conversion
- 500Hz, 250Hz, 125Hz where the division/multiplication are a straight
shift since they are power-of-two factors of 1000.
In addition, some more generally used values are made to use optimized
conversion equations rather than the generic one that uses 64-bit math,
and often results in calling compiler intrinsics.
These values are: 100Hz, 50Hz, 25Hz, 20Hz, 10Hz, 1Hz (the last one used
in some testing).
Avoiding the 64-bit math intrisics has the additional benefit, in
addition to increased performance, of using a significant lower amount
of stack space: 52 bytes on ARM Cortex-M and 80 bytes on x86.
Change-Id: I080eb338a2637d6b1c6838c119af1a9fa37fe869
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
This limits the execution contexts that will go over the loop in
_unpend_first_thread() to only ISRs of very high priority that are
preempting the system clock timer ISR, and only during the time it is
handling timeouts.
Change-Id: Iaf0500d28a2de5e077c9cf9861a5a70244127d58
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
Also remove mentions of unified kernel in various places in the kernel,
samples and documentation.
Change-Id: Ice43bc73badbe7e14bae40fd6f2a302f6528a77d
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2016-12-19 14:59:35 -05:00
Renamed from kernel/unified/include/ksched.h (Browse further)
