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Currently, rcutorture's testing of RCU priority boosting insists not
only that grace periods complete, but also that callbacks be invoked.
Although this is in fact what the user would want, ensuring that there
is sufficient CPU bandwidth devoted to callback execution is in fact
the user's responsibility. One could argue that rcutorture can take on
that responsibility, which is true in theory. But in practice, ensuring
sufficient CPU bandwidth to ksoftirqd, any rcuc kthreads, and any rcuo
kthreads is not particularly consistent with rcutorture's main job,
that of stress-testing RCU. In addition, if the system administrator
(say) makes very poor choices when pinning rcuo kthreads and then runs
rcutorture, there really isn't much rcutorture can do.
Besides, RCU priority boosting only boosts lagging readers, not all the
machinery required to invoke callbacks in a timely fashion.
This commit therefore switches rcutorture's evaluation of RCU priority
boosting from callback execution to grace-period completion by using
the new start_poll_synchronize_rcu() and poll_state_synchronize_rcu()
functions. When rcutorture is built in (as in when there is no innocent
workload to inconvenience), the ksoftirqd ktheads are boosted to real-time
priority 2 in order to allow timeouts to work properly in the face of
rcutorture's testing of RCU priority boosting.
Indeed, it is not as easy as it looks to create a reliable test of RCU
priority boosting without destroying the rest of the kernel!
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Currently, kvm-find-errors.sh assumes that if "--buildonly" appears in
the log file, then the run did builds but ran no kernels. This breaks
with kvm-remote.sh, which uses kvm.sh to do a build, then kvm-again.sh
to run the kernels built on remote systems. This commit therefore adds
a check for a kvm-remote.sh run.
While in the area, this commit checks for "--build-only" as well as
"--build-only".
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Given remote rcutorture runs, it is quite possible that the build system
will have fewer CPUs than the system(s) running the actual test scenarios.
In such cases, using the number of CPUs on the test systems can overload
the build system, slowing down the build or, worse, OOMing the build
system. This commit therefore uses the build system's CPU count to set
N in "make -jN", and by tradition sets "N" to double the CPU count.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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This commit reduces duplicate code by making kvm.sh use the new
kvm-end-run-stats.sh script rather than taking its historical approach
of open-coding it.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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This commit abstractst the end-of-run summary from kvm-again.sh, and,
while in the area, brings its format into line with that of kvm.sh.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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The kvm-again.sh script relies on shell comments added to the qemu-cmd
file, but this means that code extracting values from the QEMU command in
this file must grep out those commment. Which kvm-recheck-rcu.sh failed
to do, which destroyed its grace-period-per-second calculation. This
commit therefore adds the needed "grep -v '^#'" to kvm-recheck-rcu.sh.
Fixes: 315957cad445 ("torture: Prepare for splitting qemu execution from kvm-test-1-run.sh")
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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This commit adds a (*readlock_held)() function pointer to the
rcu_torture_ops structure in order to make the rcu_torture_one_read()
function's rcu_dereference_check() lockdep expression more appropriate
for a given run.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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This commit adds scale_type of acqrel, lock, and lock-irq to
test acquisition and release. Note that the refscale.nreaders=1
module parameter is required if you wish to test uncontended locking.
In contrast, acqrel uses a per-CPU variable, so should be just fine with
large values of the refscale.nreaders=1 module parameter.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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