From: Matt Redfearn Date: Thu, 19 Oct 2017 11:55:35 +0000 (+0100) Subject: clocksource/drivers/mips-gic-timer: Add fastpath for local timer updates X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f16ff2bdb135e2eb35488264006b575c476ea597;p=linux.git 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 Signed-off-by: Daniel Lezcano --- diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c index 775dea04460de..a04808a21d4ec 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; }