To properly exercise RCU implementations with preemptible
read-side critical sections.
+nfakewriters This is the number of RCU fake writer threads to run. Fake
+ writer threads repeatedly use the synchronous "wait for
+ current readers" function of the interface selected by
+ torture_type, with a delay between calls to allow for various
+ different numbers of writers running in parallel.
+ nfakewriters defaults to 4, which provides enough parallelism
+ to trigger special cases caused by multiple writers, such as
+ the synchronize_srcu() early return optimization.
+
stat_interval The number of seconds between output of torture
statistics (via printk()). Regardless of the interval,
statistics are printed when the module is unloaded.
shuffle_interval
The number of seconds to keep the test threads affinitied
- to a particular subset of the CPUs. Used in conjunction
- with test_no_idle_hz.
+ to a particular subset of the CPUs, defaults to 5 seconds.
+ Used in conjunction with test_no_idle_hz.
test_no_idle_hz Whether or not to test the ability of RCU to operate in
a kernel that disables the scheduling-clock interrupt to
idle CPUs. Boolean parameter, "1" to test, "0" otherwise.
+ Defaults to omitting this test.
-torture_type The type of RCU to test: "rcu" for the rcu_read_lock()
- API, "rcu_bh" for the rcu_read_lock_bh() API, and "srcu"
- for the "srcu_read_lock()" API.
+torture_type The type of RCU to test: "rcu" for the rcu_read_lock() API,
+ "rcu_sync" for rcu_read_lock() with synchronous reclamation,
+ "rcu_bh" for the rcu_read_lock_bh() API, "rcu_bh_sync" for
+ rcu_read_lock_bh() with synchronous reclamation, "srcu" for
+ the "srcu_read_lock()" API, and "sched" for the use of
+ preempt_disable() together with synchronize_sched().
verbose Enable debug printk()s. Default is disabled.
The entries are as follows:
-o "ggp": The number of counter flips (or batches) since boot.
-
o "rtc": The hexadecimal address of the structure currently visible
to readers.
o "Reader Batch": Another histogram of "ages" of structures seen
by readers, but in terms of counter flips (or batches) rather
than in terms of grace periods. The legal number of non-zero
- entries is again two. The reason for this separate view is
- that it is easier to get the third entry to show up in the
+ entries is again two. The reason for this separate view is that
+ it is sometimes easier to get the third entry to show up in the
"Reader Batch" list than in the "Reader Pipe" list.
o "Free-Block Circulation": Shows the number of torture structures