This commit adds refscale readers based on srcu_read_lock_fast_updown()
and srcu_read_lock_fast_updown() ("refscale.scale_type=srcu-fast-updown").
On my x86 laptop, these are about 2.2ns per pair.Signed-off-by: Paul E. McKenney <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: <[email protected]> --- kernel/rcu/refscale.c | 40 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c index 7429ec9f0092..07a313782dfd 100644 --- a/kernel/rcu/refscale.c +++ b/kernel/rcu/refscale.c @@ -186,6 +186,7 @@ static const struct ref_scale_ops rcu_ops = { // Definitions for SRCU ref scale testing. DEFINE_STATIC_SRCU(srcu_refctl_scale); DEFINE_STATIC_SRCU_FAST(srcu_fast_refctl_scale); +DEFINE_STATIC_SRCU_FAST_UPDOWN(srcu_fast_updown_refctl_scale); static struct srcu_struct *srcu_ctlp = &srcu_refctl_scale; static void srcu_ref_scale_read_section(const int nloops) @@ -254,6 +255,42 @@ static const struct ref_scale_ops srcu_fast_ops = { .name = "srcu-fast" }; +static bool srcu_fast_updown_sync_scale_init(void) +{ + srcu_ctlp = &srcu_fast_updown_refctl_scale; + return true; +} + +static void srcu_fast_updown_ref_scale_read_section(const int nloops) +{ + int i; + struct srcu_ctr __percpu *scp; + + for (i = nloops; i >= 0; i--) { + scp = srcu_read_lock_fast_updown(srcu_ctlp); + srcu_read_unlock_fast_updown(srcu_ctlp, scp); + } +} + +static void srcu_fast_updown_ref_scale_delay_section(const int nloops, const int udl, const int ndl) +{ + int i; + struct srcu_ctr __percpu *scp; + + for (i = nloops; i >= 0; i--) { + scp = srcu_read_lock_fast_updown(srcu_ctlp); + un_delay(udl, ndl); + srcu_read_unlock_fast_updown(srcu_ctlp, scp); + } +} + +static const struct ref_scale_ops srcu_fast_updown_ops = { + .init = srcu_fast_updown_sync_scale_init, + .readsection = srcu_fast_updown_ref_scale_read_section, + .delaysection = srcu_fast_updown_ref_scale_delay_section, + .name = "srcu-fast-updown" +}; + #ifdef CONFIG_TASKS_RCU // Definitions for RCU Tasks ref scale testing: Empty read markers. @@ -1479,7 +1516,8 @@ ref_scale_init(void) long i; int firsterr = 0; static const struct ref_scale_ops *scale_ops[] = { - &rcu_ops, &srcu_ops, &srcu_fast_ops, RCU_TRACE_OPS RCU_TASKS_OPS + &rcu_ops, &srcu_ops, &srcu_fast_ops, &srcu_fast_updown_ops, + RCU_TRACE_OPS RCU_TASKS_OPS &refcnt_ops, &percpuinc_ops, &incpercpu_ops, &incpercpupreempt_ops, &incpercpubh_ops, &incpercpuirqsave_ops, &rwlock_ops, &rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, -- 2.40.1
