diff options
Diffstat (limited to 'Documentation/RCU/torture.txt')
| -rw-r--r-- | Documentation/RCU/torture.txt | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt index a4948591607d0e..25a3c3f7d378f3 100644 --- a/Documentation/RCU/torture.txt +++ b/Documentation/RCU/torture.txt @@ -28,6 +28,15 @@ nreaders This is the number of RCU reading threads supported. 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. @@ -44,9 +53,12 @@ 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. -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. @@ -118,6 +130,21 @@ o "Free-Block Circulation": Shows the number of torture structures as it is only incremented if a torture structure's counter somehow gets incremented farther than it should. +Different implementations of RCU can provide implementation-specific +additional information. For example, SRCU provides the following: + + srcu-torture: rtc: f8cf46a8 ver: 355 tfle: 0 rta: 356 rtaf: 0 rtf: 346 rtmbe: 0 + srcu-torture: Reader Pipe: 559738 939 0 0 0 0 0 0 0 0 0 + srcu-torture: Reader Batch: 560434 243 0 0 0 0 0 0 0 0 + srcu-torture: Free-Block Circulation: 355 354 353 352 351 350 349 348 347 346 0 + srcu-torture: per-CPU(idx=1): 0(0,1) 1(0,1) 2(0,0) 3(0,1) + +The first four lines are similar to those for RCU. The last line shows +the per-CPU counter state. The numbers in parentheses are the values +of the "old" and "current" counters for the corresponding CPU. The +"idx" value maps the "old" and "current" values to the underlying array, +and is useful for debugging. + USAGE |