From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joao Martins Subject: [PATCH RFC 3/6] x86/time: streamline platform time init on plt_init() Date: Mon, 28 Dec 2015 16:59:42 +0000 Message-ID: <1451321985-13728-4-git-send-email-joao.m.martins@oracle.com> References: <1451321985-13728-1-git-send-email-joao.m.martins@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1451321985-13728-1-git-send-email-joao.m.martins@oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: Andrew Cooper , Joao Martins , Keir Fraser , Jan Beulich List-Id: xen-devel@lists.xenproject.org And use to initialize platform time solely for clocksource=tsc, as opposed to initializing platform overflow timer, which would only fire in ~180 years (on 2.2 Ghz Broadwell processor). Signed-off-by: Joao Martins --- xen/arch/x86/time.c | 41 +++++++++++++++++++++++++++++++++-------- 1 file changed, 33 insertions(+), 8 deletions(-) diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c index c9e5c14..df42d31 100644 --- a/xen/arch/x86/time.c +++ b/xen/arch/x86/time.c @@ -518,17 +518,31 @@ static s_time_t __read_platform_stime(u64 platform_time) return (stime_platform_stamp + scale_delta(diff, &plt_scale)); } +static void __plt_init(void) +{ + u64 count; + + ASSERT(spin_is_locked(&platform_timer_lock)); + count = plt_src.read_counter(); + plt_stamp64 += (count - plt_stamp) & plt_mask; + plt_stamp = count; +} + +static void plt_init(void) +{ + spin_lock_irq(&platform_timer_lock); + __plt_init(); + spin_unlock_irq(&platform_timer_lock); +} + static void plt_overflow(void *unused) { int i; - u64 count; s_time_t now, plt_now, plt_wrap; spin_lock_irq(&platform_timer_lock); - count = plt_src.read_counter(); - plt_stamp64 += (count - plt_stamp) & plt_mask; - plt_stamp = count; + __plt_init(); now = NOW(); plt_wrap = __read_platform_stime(plt_stamp64); @@ -635,11 +649,22 @@ static void __init init_platform_timer(void) set_time_scale(&plt_scale, pts->frequency); - plt_overflow_period = scale_delta( - 1ull << (pts->counter_bits-1), &plt_scale); - init_timer(&plt_overflow_timer, plt_overflow, NULL, 0); plt_src = *pts; - plt_overflow(NULL); + + if ( clocksource_is_tsc ) + { + plt_init(); + } + else + { + plt_overflow_period = scale_delta( + 1ull << (pts->counter_bits-1), &plt_scale); + init_timer(&plt_overflow_timer, plt_overflow, NULL, 0); + plt_overflow(NULL); + + printk("Platform timer overflow period is %lu secs\n", + plt_overflow_period/1000000000); + } platform_timer_stamp = plt_stamp64; stime_platform_stamp = NOW(); -- 2.1.4