From: Joao Martins <joao.m.martins@oracle.com>
To: xen-devel@lists.xen.org
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Joao Martins <joao.m.martins@oracle.com>,
Keir Fraser <keir@xen.org>, Jan Beulich <jbeulich@suse.com>
Subject: [PATCH 3/5] x86/time: streamline platform time init on plt_init()
Date: Thu, 17 Mar 2016 09:12:14 -0700 (PDT) [thread overview]
Message-ID: <1458231136-13457-4-git-send-email-joao.m.martins@oracle.com> (raw)
In-Reply-To: <1458231136-13457-1-git-send-email-joao.m.martins@oracle.com>
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 <joao.m.martins@oracle.com>
---
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Changes since RFC:
- Move clocksource_is_tsc variable to this patch.
- s/1000000000/SECONDS(1)
---
xen/arch/x86/time.c | 44 +++++++++++++++++++++++++++++++++++---------
1 file changed, 35 insertions(+), 9 deletions(-)
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 1311c58..5af8902 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -434,6 +434,7 @@ uint64_t ns_to_acpi_pm_tick(uint64_t ns)
/************************************************************
* PLATFORM TIMER 4: TSC
*/
+static bool_t clocksource_is_tsc = 0;
static u64 tsc_freq;
static unsigned long tsc_max_warp;
static void tsc_check_reliability(void);
@@ -466,7 +467,7 @@ static int __init init_tsctimer(struct platform_timesource *pts)
}
pts->frequency = tsc_freq;
- return tsc_reliable;
+ return ( clocksource_is_tsc = tsc_reliable );
}
static u64 read_tsc(void)
@@ -516,17 +517,31 @@ 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);
@@ -633,11 +648,22 @@ 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/SECONDS(1));
+ }
platform_timer_stamp = plt_stamp64;
stime_platform_stamp = NOW();
--
2.1.4
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-03-17 16:12 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-17 16:12 [PATCH 0/5] x86/time: PVCLOCK_TSC_STABLE_BIT support Joao Martins
2016-03-17 16:12 ` [PATCH 1/5] public/xen.h: add flags field to vcpu_time_info Joao Martins
2016-03-18 20:12 ` Andrew Cooper
2016-03-21 11:42 ` Joao Martins
2016-03-21 11:43 ` Andrew Cooper
2016-03-21 11:51 ` Joao Martins
2016-03-21 15:10 ` Jan Beulich
2016-03-21 15:27 ` Andrew Cooper
2016-03-21 15:40 ` Joao Martins
2016-03-17 16:12 ` [PATCH 2/5] x86/time: implement tsc as clocksource Joao Martins
2016-03-18 20:21 ` Andrew Cooper
2016-03-21 11:43 ` Joao Martins
2016-03-22 12:41 ` Joao Martins
2016-03-22 12:46 ` Jan Beulich
2016-03-22 15:51 ` Joao Martins
2016-03-22 16:02 ` Jan Beulich
2016-03-22 20:40 ` Joao Martins
2016-03-23 7:28 ` Jan Beulich
2016-03-23 12:05 ` Joao Martins
2016-03-23 14:05 ` Jan Beulich
2016-03-17 16:12 ` Joao Martins [this message]
2016-03-18 20:32 ` [PATCH 3/5] x86/time: streamline platform time init on plt_init() Andrew Cooper
2016-03-21 11:45 ` Joao Martins
2016-03-17 16:12 ` [PATCH 4/5] x86/time: refactor read_platform_stime() Joao Martins
2016-03-18 20:34 ` Andrew Cooper
2016-03-21 11:45 ` Joao Martins
2016-03-21 13:08 ` Andrew Cooper
2016-03-17 16:12 ` [PATCH 5/5] x86/time: implement PVCLOCK_TSC_STABLE_BIT Joao Martins
2016-03-18 20:58 ` Andrew Cooper
2016-03-21 11:50 ` Joao Martins
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1458231136-13457-4-git-send-email-joao.m.martins@oracle.com \
--to=joao.m.martins@oracle.com \
--cc=andrew.cooper3@citrix.com \
--cc=jbeulich@suse.com \
--cc=keir@xen.org \
--cc=xen-devel@lists.xen.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).