Commit-ID: f16ff2bdb135e2eb35488264006b575c476ea597
Gitweb: https://git.kernel.org/tip/f16ff2bdb135e2eb35488264006b575c476ea597
Author: Matt Redfearn <matt.redfearn@xxxxxxxx>
AuthorDate: Thu, 19 Oct 2017 12:55:35 +0100
Committer: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
CommitDate: Thu, 19 Oct 2017 23:51:31 +0200
clocksource/drivers/mips-gic-timer: Add fastpath for local timer updates
Always accessing the compare register via the CM redirect region is
(relatively) slow. If the timer being updated is the current CPUs
then this can be shortcutted by writing to the CM VP local region.
Signed-off-by: Matt Redfearn <matt.redfearn@xxxxxxxx>
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
---
drivers/clocksource/mips-gic-timer.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index 775dea0..a04808a 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -39,13 +39,18 @@ static u64 notrace gic_read_count(void)
static int gic_next_event(unsigned long delta, struct clock_event_device *evt)
{
+ int cpu = cpumask_first(evt->cpumask);
u64 cnt;
int res;
cnt = gic_read_count();
cnt += (u64)delta;
- write_gic_vl_other(mips_cm_vp_id(cpumask_first(evt->cpumask)));
- write_gic_vo_compare(cnt);
+ if (cpu == raw_smp_processor_id()) {
+ write_gic_vl_compare(cnt);
+ } else {
+ write_gic_vl_other(mips_cm_vp_id(cpu));
+ write_gic_vo_compare(cnt);
+ }
res = ((int)(gic_read_count() - cnt) >= 0) ? -ETIME : 0;
return res;
}
--
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