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| author | Ingo Molnar <mingo@kernel.org> | 2020-07-31 00:15:53 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-07-31 00:15:53 +0200 |
| commit | c1cc4784ce6e8cceff1013709abd74bcbf7fbf24 (patch) | |
| tree | 5eaacf62240ec85a6ad9c7594e8ad8f7f783afc2 /kernel/rcu/rcuperf.c | |
| parent | 92ed301919932f777713b9172e525674157e983d (diff) | |
| parent | 13625c0a4074d3bab61b1dc70a828b574255f339 (diff) | |
| download | lwn-c1cc4784ce6e8cceff1013709abd74bcbf7fbf24.tar.gz lwn-c1cc4784ce6e8cceff1013709abd74bcbf7fbf24.zip | |
Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull the v5.9 RCU bits from Paul E. McKenney:
- Documentation updates
- Miscellaneous fixes
- kfree_rcu updates
- RCU tasks updates
- Read-side scalability tests
- SRCU updates
- Torture-test updates
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/rcu/rcuperf.c')
| -rw-r--r-- | kernel/rcu/rcuperf.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c index 9eb39c20082c..ec903d781778 100644 --- a/kernel/rcu/rcuperf.c +++ b/kernel/rcu/rcuperf.c @@ -69,6 +69,11 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>"); * value specified by nr_cpus for a read-only test. * * Various other use cases may of course be specified. + * + * Note that this test's readers are intended only as a test load for + * the writers. The reader performance statistics will be overly + * pessimistic due to the per-critical-section interrupt disabling, + * test-end checks, and the pair of calls through pointers. */ #ifdef MODULE @@ -309,8 +314,10 @@ static void rcu_perf_wait_shutdown(void) } /* - * RCU perf reader kthread. Repeatedly does empty RCU read-side - * critical section, minimizing update-side interference. + * RCU perf reader kthread. Repeatedly does empty RCU read-side critical + * section, minimizing update-side interference. However, the point of + * this test is not to evaluate reader performance, but instead to serve + * as a test load for update-side performance testing. */ static int rcu_perf_reader(void *arg) @@ -576,11 +583,8 @@ static int compute_real(int n) static int rcu_perf_shutdown(void *arg) { - do { - wait_event(shutdown_wq, - atomic_read(&n_rcu_perf_writer_finished) >= - nrealwriters); - } while (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters); + wait_event(shutdown_wq, + atomic_read(&n_rcu_perf_writer_finished) >= nrealwriters); smp_mb(); /* Wake before output. */ rcu_perf_cleanup(); kernel_power_off(); @@ -693,11 +697,8 @@ kfree_perf_cleanup(void) static int kfree_perf_shutdown(void *arg) { - do { - wait_event(shutdown_wq, - atomic_read(&n_kfree_perf_thread_ended) >= - kfree_nrealthreads); - } while (atomic_read(&n_kfree_perf_thread_ended) < kfree_nrealthreads); + wait_event(shutdown_wq, + atomic_read(&n_kfree_perf_thread_ended) >= kfree_nrealthreads); smp_mb(); /* Wake before output. */ |