linux/kernel/rcu/Kconfig.debug, branch v5.9

refperf: Rename RCU_REF_PERF_TEST to RCU_REF_SCALE_TEST

2020-06-29T19:00:46Z

The old Kconfig option name is all too easy to conflate with the unrelated "perf" feature, so this commit renames RCU_REF_PERF_TEST to RCU_REF_SCALE_TEST. Reported-by: Ingo Molnar Signed-off-by: Paul E. McKenney

refperf: Add a test to measure performance of read-side synchronization

2020-06-29T19:00:44Z

Add a test for comparing the performance of RCU with various read-side synchronization mechanisms. The test has proved useful for collecting data and performing these comparisons. Currently RCU, SRCU, reader-writer lock, reader-writer semaphore and reference counting can be measured using refperf.perf_type parameter. Each invocation of the test runs measures performance of a specific mechanism. The maximum number of CPUs to concurrently run readers on is chosen by the test itself and is 75% of the total number of CPUs. So if you had 24 CPUs, the test runs with a maximum of 18 parallel readers. A number of experiments are conducted, and in each experiment, the number of readers is increased by 1, upto the 75% of CPUs mark. During each experiment, all readers execute an empty loop with refperf.loops iterations and time the total loop duration. This is then averaged. Example output: Parameters "refperf.perf_type=srcu refperf.loops=2000000" looks like: [ 3.347133] srcu-ref-perf: [ 3.347133] Threads Time(ns) [ 3.347133] 1 36 [ 3.347133] 2 34 [ 3.347133] 3 34 [ 3.347133] 4 34 [ 3.347133] 5 33 [ 3.347133] 6 33 [ 3.347133] 7 33 [ 3.347133] 8 33 [ 3.347133] 9 33 [ 3.347133] 10 33 [ 3.347133] 11 33 [ 3.347133] 12 33 [ 3.347133] 13 33 [ 3.347133] 14 33 [ 3.347133] 15 32 [ 3.347133] 16 33 [ 3.347133] 17 33 [ 3.347133] 18 34 Signed-off-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney

rcutorture: Add torture tests for RCU Tasks Trace

2020-04-27T18:03:51Z

This commit adds the definitions required to torture the tracing flavor of RCU tasks. Signed-off-by: Paul E. McKenney

rcutorture: Add torture tests for RCU Tasks Rude

2020-04-27T18:03:51Z

This commit adds the definitions required to torture the rude flavor of RCU tasks. Signed-off-by: Paul E. McKenney

rcu: Add support for consolidated-RCU reader checking

2019-08-09T18:00:35Z

This commit adds RCU-reader checks to list_for_each_entry_rcu() and hlist_for_each_entry_rcu(). These checks are optional, and are indicated by a lockdep expression passed to a new optional argument to these two macros. If this optional lockdep expression is omitted, these two macros act as before, checking for an RCU read-side critical section. Signed-off-by: Joel Fernandes (Google) [ paulmck: Update to eliminate return within macro and update comment. ] Signed-off-by: Paul E. McKenney

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46Z

Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

rcu: Move RCU debug Kconfig options to kernel/rcu

2017-06-09T01:52:44Z

RCU's debugging Kconfig options are in the unintuitive location lib/Kconfig.debug, and there are enough of them that it would be good for them to be more centralized. This commit therefore extracts RCU's Kconfig options from init/Kconfig into a new kernel/rcu/Kconfig.debug file. Reported-by: Ingo Molnar Signed-off-by: Paul E. McKenney