linux/tools/testing/selftests/rcutorture
Paul E. McKenney adcfe76c61 torture: Default jitter off when running rcuperf
The purpose of jitter is to expose concurrency bugs due to invalid
assumptions about forward progress.  There is usually little point
in jitter when measuring performance.  This commit therefore defaults
jitter off when running rcuperf.  You can override this by specifying
the kvm.sh "--jitter" argument -after- the "--torture rcuperf"
argument.  No idea why you would want this, but if you do, that is
how you do it.

One example of a conccurrency bug that this jitter might expose is one
in which the developer assumed that a given short region of code would be
guaranteed to execute within some short time limit.  Such assumptions are
invalid in virtualized environments because the hupervisor can preempt
the guest OS at any point, even when the guest OS thinks that it has
disabled interrupts.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2018-02-20 16:22:00 -08:00
..
bin torture: Default jitter off when running rcuperf 2018-02-20 16:22:00 -08:00
configs torture: Eliminate torture_runnable and perf_runnable 2017-12-11 09:18:29 -08:00
doc rcu: Drive TASKS_RCU directly off of PREEMPT 2017-08-17 07:26:04 -07:00
formal/srcu-cbmc Merge branch 'linus' into locking/core, to resolve conflicts 2017-11-07 10:32:44 +01:00
.gitignore torture: Remove obsolete files from rcutorture .gitignore 2016-11-14 10:48:51 -08:00