From e20e6771e628ed3470248003550abe2e823c7fdb Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Mon, 11 Mar 2013 16:23:46 -0500 Subject: [PATCH] --- yaml --- r: 374187 b: refs/heads/master c: 023796b9be3a77481cd5ee0b64a13a55bb0d5df4 h: refs/heads/master i: 374185: 68115c90068ea5852601993c0240a4559588c7da 374183: 2bcd6804a818ab5c14483719102da7f88ca78988 v: v3 --- [refs] | 2 +- trunk/arch/arm/kernel/arch_timer.c | 18 +++++++++++++----- 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/[refs] b/[refs] index 1dd761d3baa0..755df24140b7 100644 --- a/[refs] +++ b/[refs] @@ -1,2 +1,2 @@ --- -refs/heads/master: 7e48c0b9d9ab07c92cd26f167010cd5a50eb0cec +refs/heads/master: 023796b9be3a77481cd5ee0b64a13a55bb0d5df4 diff --git a/trunk/arch/arm/kernel/arch_timer.c b/trunk/arch/arm/kernel/arch_timer.c index d957a51435d8..80c458fc4a30 100644 --- a/trunk/arch/arm/kernel/arch_timer.c +++ b/trunk/arch/arm/kernel/arch_timer.c @@ -22,9 +22,11 @@ static unsigned long arch_timer_read_counter_long(void) return arch_timer_read_counter(); } -static u32 arch_timer_read_counter_u32(void) +static u32 sched_clock_mult __read_mostly; + +static unsigned long long notrace arch_timer_sched_clock(void) { - return arch_timer_read_counter(); + return arch_timer_read_counter() * sched_clock_mult; } static struct delay_timer arch_delay_timer; @@ -52,10 +54,16 @@ int __init arch_timer_of_register(void) int __init arch_timer_sched_clock_init(void) { - if (arch_timer_get_rate() == 0) + u32 arch_timer_rate = arch_timer_get_rate(); + + if (arch_timer_rate == 0) return -ENXIO; - setup_sched_clock(arch_timer_read_counter_u32, - 32, arch_timer_get_rate()); + /* Cache the sched_clock multiplier to save a divide in the hot path. */ + sched_clock_mult = NSEC_PER_SEC / arch_timer_rate; + sched_clock_func = arch_timer_sched_clock; + pr_info("sched_clock: ARM arch timer >56 bits at %ukHz, resolution %uns\n", + arch_timer_rate / 1000, sched_clock_mult); + return 0; }