This commit adds new k_work_poll interface. It allows to
submit given work to a workqueue automatically when one of the
watched pollable objects changes its state.
Signed-off-by: Piotr Zięcik <piotr.ziecik@nordicsemi.no>
Signed-off-by: Peter A. Bigot <pab@pabigot.com>
Disabling SMP mode for certain tests was a one-release thing, done to
avoid having to triage every test independently (MANY are not
SMP-safe), and with the knowledge that it was probably hiding bugs in
the kernel.
Turn it on pervasively. Tests are treated with a combination of
flagging specific cases as "1cpu" where we have short-running tests
that can be independently run in an otherwise SMP environment, and via
setting CONFIG_MP_NUM_CPUS=1 where that's not possible (which still
runs the full SMP kernel config, but with only one CPU available).
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
(Chunk 3 of 3 - this patch was split across pull requests to address
CI build time limitations)
Zephyr has always been a uniprocessor system, and its kernel tests are
rife with assumptions and outright dependence on single-CPU operation
(for example: "low priority threads will never run until this high
priority thread blocks" -- not true if there's another processor to
run it!)
About 1/3 of our tests fail right now on x86_64 when dual processor
operation is made default. Most of those can probably be recovered on
a case-by-case basis with simple changes (and a few of them might
represent real bugs in SMP!), but for now let's make sure the full
test suite passes by turning the second CPU off. There's still plenty
of SMP coverage in the remaining cases.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Qemu doesn't like tickless. By default[1] it tries to be realtime as
vied by the host CPU -- presenting read values from hardware cycle
counters and interrupt timings at the appropriate real world clock
times according to whatever the simulated counter frequency is. But
when the host system is loaded, there is always the problem that the
qemu process might not see physical CPU time for large chunks of time
(i.e. a host OS scheduling quantum -- generally about the same size as
guest ticks!) leading to lost cycles.
When those timer interrupts are delivered by the emulated hardware at
fixed frequencies without software intervention, that's not so bad:
the work the guest has to do after the interrupt generally happens
synchronously (because the qemu process has just started running) and
nothing notices the dropout.
But with tickless, the interrupts need to be explicitly programmed by
guest software! That means the driver needs to be sure it's going to
get some real CPU time within some small fraction of a Zephyr tick of
the right time, otherwise the computations get wonky.
The end result is that qemu tends to work with tickless well on an
unloaded/idle run, but not in situations (like sanitycheck) where it
needs to content with other processes for host CPU.
So, add a flag that drivers can use to "fake" tickless behavior when
run under qemu (only), and enable it (only!) for the small handful of
tests that are having trouble.
[1] There is an -icount feature to implement proper cycle counting at
the expense of real-world-time correspondence. Maybe someday we might
get it to work for us.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
